So today I discovered the reserve switch doesn't work!! On the plus side I did get 400ks before pushing............
Tom,
You may find that the reserve switch was just in the "ON" position all the time.
OR, it just doesn't work, as in allows all the petrol to flow out of the tank keeping none in reserve.
In either case, you used all the fuel the tank can hold. :-)
I too, once got to exactly 400kms - and then was pushing.
Cheers,
Arnie
I to found out the reserve never worked........the hard way.........wanted to see where reserve kicked in.... Don't work.... When it reads empty its empty!
I haven't ever tested the "reserve" feature of my '92. That may be due to it no longer functioning properly, or it may be that I've never let the tank get low enough for the feature to kick in.
Ours uses an electronic "cutout" reserve...That means two cylinders will cut out giving you the impression you're running low on fuel and prompting you to flick the switch to "Reserve." The owner's manual states the total capacity of the fuel tank as 5.8 US gallons (4.8 Imperial gallons). It puts the reserve at 1.3 US gallons (1.1 Imp Gal) of that total. So, at 4.5 gallons used, or between 200 and 225 miles (45-50MPG), I should feel the cutout.
My question is, what triggers the system? Is it a particular Ohm value on the in-tank level sender? Is it a fuel gauge needle position?
Cap'n Ron. . .
G'day.
I'm well curious about this. My 1tx doesn't do that. And I'm even more certain because since I dropped her the reserve switch has been smashed out, I get the red light and nothing else, no cutout just keeps going till empty. Anyone else have a beautiful ambulance that does this? Wondering if I even HAVE a fuel pump!!!!!
Cheers
Neil
Quote from: NJona86FJ on September 25, 2013, 03:46:55 PM
G'day.
I'm well curious about this. My 1tx doesn't do that. And I'm even more certain because since I dropped her the reserve switch has been smashed out, I get the red light and nothing else, no cutout just keeps going till empty. Anyone else have a beautiful ambulance that does this? Wondering if I even HAVE a fuel pump!!!!!
Cheers
Neil
Up to the '87 model year used gravity-feed. '89 through '93 used a fuel pump.
Where do you have a red fuel light? In the 1993 Australian PDF owners manual (the only one I could find), it shows a low fuel indicator light on the dash in the location where my ABS light is located... Do non-ABS bikes have this low fuel light? It should be just below and right of the left turn signal indicator.
Cap'n Ron. . .
My 86' has the low fuel light and it still works. The fuel cut off (Simulated reserve) also worked on my 86' until I upgraded to an 84/85 petcock. The harness and connector is still in place should I ever want that function back. But till I had my FJ I never had a fuel level gage or low warning light. Using the trip meter is instinct for me.
Quote from: Capn Ron on September 25, 2013, 03:33:20 PM
I haven't ever tested the "reserve" feature of my '92. That may be due to it no longer functioning properly, or it may be that I've never let the tank get low enough for the feature to kick in.
Ours uses an electronic "cutout" reserve...That means two cylinders will cut out giving you the impression you're running low on fuel and prmpting you to flick the switch to "Reserve." The owner's manual states the total capacity of the fuel tank as 5.8 US gallons (4.8 Imperial gallons). It puts the reserve at 1.3 US gallons (1.1 Imp Gal) of that total. So, at 4.5 gallons used, or between 200 and 225 miles (45-50MPG), I should feel the cutout.
My question is, what triggers the system? Is it a particular Ohm value on the in-tank level sender? Is it a fuel guage needle position?
Cap'n Ron. . .
I am in the process of cleaning the inside of my tank I have the sender out and it appears that there is a small sensor that I suspect is a simple on/off sensor.
I think this feeds into a circuit going to the 4 prong ignition control connector that plugs into the CDI / Ignitor.
A theory is while the in tank sensor is shorted (on, fuel above the sensor) things are great, but when it is open (off, fuel below the sensor), low fuel.. It sends a signal to the ignitor to turn off the fuel pump relay voltage thus starving the engine. If you don't reestablish fuel pump power you die..
When you switch on the reserve rocker switch you are simply bypassing the fuel cut off signal and reestablish power back to the fuel pump. ? Be interesting to have a green light on the voltage line going to the fuel pump relay (or fuel pump B+) to test this... :morning2: :pardon:.
I have never liked the wording on the reserve switch. "RES" and "ON".... You would think that "RES ON" and "RES OFF" might make more since, but hey, I am dyslexic most days anyhow.... It would be fairly easy to have the switch set in the wrong position. There again maybe a reserve on light might be helpful.
And as long as things are coming from my head and leaking out into fingers here, they could have taken the space on the 88- 93's where that stupid clock is and used it for a light or better yet a voltmeter... :lol: Things to ponder.
George
Quote from: movenon on September 25, 2013, 04:37:39 PM
A theory is while the in tank sensor is shorted (on, fuel above the sensor) things are great, but when it is open (off, fuel below the sensor), low fuel.. It sends a signal to the ignitor to turn off the fuel pump relay voltage thus starving the engine. If you don't reestablish fuel pump power you die..
When you switch on the reserve rocker switch you are simply bypassing the fuel cut off signal and reestablish power back to the fuel pump.
George
This is exactly the way I believe it works George.
Since I installed the Dyna 2000 ignition, I no longer have the OEM ignition box connected to the harness. So I no longer have a reserve function, and the rocker switch is always in the bypass position...... I now use that switch as an anti-theft device - switch it to the non-bypass position and the bike won't go very far!
Just as an aside, disconnecting the OEM box also disables the sidestand switch cut-out, so the bike won't crack if in gear (clutch in or out), but it will keep running if the sidestand is extended while in gear. And the clutch switch activates a light on the digital dash when the lever is pulled (clutch dis-engaged). One day I will get around to re-wiring it to address these - one day!.......In the meantime I just ride and have learned to live with these little inconsistencies!
Cheers
Harvy
My understanding is that the sputtering you get from the engine when you hit the reserve level is the ignition being cut out on two of the cylinders??
I like that you are seeing a small sensor (switch?) on the fuel level sender... Is there a separate wire from that switch to the harness? As in a signal wire for the resistance of the level sender for fuel gauge function and a separate circuit for the small switch? If so, that would make perfect sense.
I agree that the reserve switch on the dash should have been labeled differently. Maybe "Res" and "Main"??
I like the clock...keeps me in check on long touring days and through different time zones. I would like more info though...oil temp sender and readout is next on my agenda...then Randy's oil cooler...then I can report the improvement. A volt meter would also be handy to establish a baseline so you could spot charging/battery issues early on.
Cap'n Ron. . .
I found a post on the web regarding the reserve not working on a guy's FJ. The rocker switch contacts were so corroded that the reserve circuit was always treated as "open":
(http://2.bp.blogspot.com/-szJPQPG8jTs/UMQ6pO5zgcI/AAAAAAAAAJ8/67XcqFt2jT4/s1600/P1000685.JPG)
He did a nice job of cleaning up the contacts and his reserve feature is now functioning as designed:
(http://4.bp.blogspot.com/-MdbuzOjSDsM/UMQ6pHnyRUI/AAAAAAAAAKA/iGsZCrFO_4U/s1600/P1000691.JPG)
Cap'n Ron. . .
Quote from: Capn Ron on September 25, 2013, 05:40:40 PM
My understanding is that the sputtering you get from the engine when you hit the reserve level is the ignition being cut out on two of the cylinders??
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Quote from: Pat Conlon on September 25, 2013, 05:55:00 PM
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Because it interrupts the ignition circuit on both of my 86's as they do not have fuel pumps...
Thing that make you go hmmmm :scratch_one-s_head:
Randy - RPM
Quote from: Capn Ron on September 25, 2013, 05:40:40 PM
My understanding is that the sputtering you get from the engine when you hit the reserve level is the ignition being cut out on two of the cylinders??
It has been said categorically here (by someone else thank goodness) that this is a myth. I agree.
If the coils were cutting out there would be an
immediate return to normal operation once the switch is flicked. There is not.
I believe it cuts the fuel pump out.
The behaviour of the motor, both when it indicates the need to go to reserve and when the switch is operated is entirely consistant with this. That is, it takes a few seconds to kick back in after it has been flicked. That lag is the time it takes for the bowls to refill.
A motor deprived of fuel or spark has entirely different characteristics and the function of the reserve switch is consistant with fuel starvation, not spark interruption.'
For those that need it proved, it would be a simple test.
Noel
Quote from: racerrad8 on September 25, 2013, 06:02:23 PM
Quote from: Pat Conlon on September 25, 2013, 05:55:00 PM
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Because it interrupts the ignition circuit on both of my 86's as they do not have fuel pumps...
Of course, that explains it.....
Quote from: Pat Conlon on September 25, 2013, 07:06:59 PM
Quote from: racerrad8 on September 25, 2013, 06:02:23 PM
Quote from: Pat Conlon on September 25, 2013, 05:55:00 PM
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Because it interrupts the ignition circuit on both of my 86's as they do not have fuel pumps...
Of course, that explains it.....
Not entirely, it still seems to be a widely held belief with the fuel pump models.
Quote from: Capn Ron on September 25, 2013, 03:33:20 PM
Ours uses an electronic "cutout" reserve...That means two cylinders will cut out giving you the impression you're running low on fuel and prompting you to flick the switch to "Reserve." The owner's manual states the total capacity of the fuel tank as 5.8 US gallons
Cap'n Ron. . .
It does NOT "cut out 2 cylinders"!!! It shuts OFF the fuel pump, causing the carbs to ACTUALLY RUN OUT OF GAS..... Please stop perpetuating this MYTH! :mad:
When the low fuel light comes on solid, it signals the fuel pump relay to turn OFF, switching the rocker switch to reserve turns the pump back on.
Quote from: ribbert on September 25, 2013, 06:24:56 PM
It has been said categorically here (by someone else thank goodness) that this is a myth. I agree.
If the coils were cutting out there would be an immediate return to normal operation once the switch is flicked. There is not.
I believe it cuts the fuel pump out.
The behaviour of the motor, both when it indicates the need to go to reserve and when the switch is operated is entirely consistant with this. That is, it takes a few seconds to kick back in after it has been flicked. That lag is the time it takes for the bowls to refill.
A motor deprived of fuel or spark has entirely different characteristics and the function of the reserve switch is consistant with fuel starvation, not spark interruption.'
For those that need it proved, it would be a simple test.
Noel
I agree with you , Noel, at least for the fuel pump models. (I know... :shok: )
The 'myth' was printed in one of the major magazine road tests of the day... I remember reading it. I can't find it right right now, but this site poster seems to have 'cut and pasted' the text pretty much as I remember reading it, back in the day:
http://fjrireland.smfforfree2.com/index.php?topic=3.0 (http://fjrireland.smfforfree2.com/index.php?topic=3.0)
Electrical system
The FJ1200 features a standard 12 volt electrical system. The alternator and starter motor are mounted behind the cylinders. Yamaha's self cancelling indicator unit is used and a variable resistance gauging system is used to monitor engine oil contents with associated warning lights. A large fuel gauge is provided as is a low level warning light. Nippondenso Transistor Controlled Ignition (TCI) is used in conjunction with two coils.
The FJ1200 fuel reserve system is unusual in that when the fuel level reaches approximately 5 litres remaining ignition is cut to two cylinders giving the impression that the vehicle is running out of fuel, a reserve switch mounted in the fairing restores the cut cylinders allowing the rider to continue normally.[7]
Unfortunately, his source isn't listed. :dash2:
Quote from: Pat Conlon on September 25, 2013, 07:06:59 PM
Of course, that explains it.....
(http://www.smileyvault.com/albums/forum/smileyvault-stirthepot.gif) (http://www.smileyvault.com/)
Quote from: ribbert on September 25, 2013, 07:43:02 PM
Quote from: Pat Conlon on September 25, 2013, 07:06:59 PM
Quote from: racerrad8 on September 25, 2013, 06:02:23 PM
Quote from: Pat Conlon on September 25, 2013, 05:55:00 PM
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Because it interrupts the ignition circuit on both of my 86's as they do not have fuel pumps...
Of course, that explains it.....
Not entirely, it still seems to be a widely held belief with the fuel pump models.
I'm pretty sure the petcock, on the gravity-feed models, has a solenoid that closes the output off when the low fuel light comes on, simulating an out-of-fuel condition, same as the fuel pump bikes. That is why disconnecting the electrical connector to the petcock disables the reserve function....
So, it was a mis-firing on the early bikes and a fuel-pump shut off on the later bikes? That would explain my confusion at least. And the point of ignition cut-off and fuel cut-off having very different performance effects on the engine is a good one.
I sit corrected...at least on the fuel pump models. :hi:
Cap'n Ron. . .
Quote from: RichBaker on September 25, 2013, 07:58:24 PM
I'm pretty sure the petcock, on the gravity-feed models, has a solenoid that closes the output off when the low fuel light comes on, simulating an out-of-fuel condition, same as the fuel pump bikes. That is why disconnecting the electrical connector to the petcock disables the reserve function....
Going into the garage to check my old 86 petcock...
Cap'n,
See my last post, above yours.... I need to go thru the wiring diagrams for the 84-85, and 86-87 bikes, but I'm pretty sure NONE of them cut out 2 cylinders. I'm pretty sure they all cut fuel....
Crap, I gave that part to Keand3 some time ago.... Sorry...
Quote from: not a lib on September 25, 2013, 07:54:04 PM
I agree with you , Noel, at least for the fuel pump models. (I know... :shok: )
The 'myth' was printed in one of the major magazine road tests of the day... I remember reading it. I can't find it right right now, but this site poster seems to have 'cut and pasted' the text pretty much as I remember reading it, back in the day:
http://fjrireland.smfforfree2.com/index.php?topic=3.0 (http://fjrireland.smfforfree2.com/index.php?topic=3.0)
Electrical system
The FJ1200 fuel reserve system is unusual in that when the fuel level reaches approximately 5 litres remaining ignition is cut to two cylinders giving the impression that the vehicle is running out of fuel, a reserve switch mounted in the fairing restores the cut cylinders allowing the rider to continue normally.[7]
Thanks for posting that...I read that same article back in the day. It never occurred to me that they would change the way the reserve indication happens. Before this campfire goes out, we'll have it settled, I'm sure. :yes:
Cap'n Ron. . .
IIRC, Frank Moore found that disconnecting the petcock connector disabled the reserve function on the ambulances....
Quote from: racerrad8 on September 25, 2013, 06:02:23 PM
Quote from: Pat Conlon on September 25, 2013, 05:55:00 PM
Negative Ron, It is just as George explains it above ^^^ it is a fuel pump interrupt.
I wonder where this 'ignition interrupt' idea keeps coming from?
We have been hearing it often....
Because it interrupts the ignition circuit on both of my 86's as they do not have fuel pumps...
Thing that make you go hmmmm :scratch_one-s_head:
Randy - RPM
Going to have to think about the 84-87 FJ's (stare into the digital camp fire) .
Different TCI/CDI/Ignitor box in the 84 - 87's. The 88-93's have a different ignitor box and wiring. In the newer ignitors there is a wire e from the fuel tank reserve sensor to the ignitor box and a wire going from the ignitor to the coil of the fuel pump relay, it is the grounding side of the coil. When that "grounding" leg is interrupted by the fuel tank reserve sensor the fuel pump relay coil circuit turns off (going to die, "may, day going down"). :dash2:
Also going to the ignitor is one leg of the reserve switch to the ignitor box reestablish a ground condition inside the ignitor box for the fuel pump relay to relatch (great, now find a gas station). ??
Ron, the fuel sender has 3 wires. One ground, one fuel level and the other is from the "fuel low" sensor. Without tearing the little sensor apart I can't tell you how it operates. From the diagram it roughly looks like a balancing circuit between 2 resistors, when one side (the sensor) get enough out of balance it sends a signal to the ignitor. That's the best I can explain it.
Now can someone explain a 84-86 fuel reserve system as I don't one. :good2: :drinks:
George
OK the above post's gives me a good idea on how the early bikes work. The bottom line seems to be that all the FJ's by hook or crook cut the fuel off. Not the igntion system which makes more engineering since.
George, the 84/85's don't have the wonky reserve...just a low fuel level light (plus fuel gauge and odometer) that's why it is popular on the gravity flow 86/87's to retrofit the less expensive 84/85 petcock...to get away from the reserve switch.
I would like to confirm the nature of the interruption on the 86/87s.... fuel or ignition?
I'm almost certain the interruption on my '92 is at the fuel pump for just the reason Noel pointed out.
It takes a moment for my '92 to recover when switching to reserve....time for the fuel bowls to refill.
If it were ignition.....it would be immediate.
I'm at work, don't have a copy of my GYSM, but the complete description of how this works IS in there.... I don't want to download the copies available in the files section, too much hassle with the LAN here....
Quote from: Pat Conlon on September 25, 2013, 09:21:41 PM
George, the 84/85's don't have the wonky reserve...just a low fuel level light (plus fuel gauge and odometer) that's why it is popular on the gravity flow 86/87's to retrofit the less expensive 84/85 petcock...to get away from the reserve switch.
I would like to confirm the nature of the interruption on the 86/87s.... fuel or ignition?
I'm almost certain the interruption on my '92 is at the fuel pump for just the reason Noel pointed out.
It takes a moment for my '92 to recover when switching to reserve....time for the fuel bowls to refill.
If it were ignition.....it would be immediate.
I am convinced from the wiring diagrams that all the newer bikes work by cutting the ground leg of the fuel pump relay breaking that circuit. They fuel starve.
I have a poor copy of an 86 - 87 wiring diagram and can see the reserve switch and the solenoid to control the fuel. The diagram I have is real small and hard to read.
George
That would explain the reason for the wires on the 86/87 petcock.... (And thus the higher cost)
G'day
Ok my fuel light is on the dash on the LH side between the speedo and tachometer,up high but below the neutral and turn signal. It gets brighter the less I have, and you can make it go out by stopping hardish. I have ridden it too empty a few times without flipping the reserve switch. I honestly think it makes no difference on my bike. Know this for certain as I have a reserve switch no more. I am losing fuel though, not sure all this talk of fuel systems makes me think its time to have a bo peep in there maybe replace a few odd hoses. ( this will possibly be another thread)
Just to throw a spanner in the works. :hi:
Cheers
Neil
:hi: oh and just asking but if the ignition cut on 2cylinders would this not have potential to destroy engines? Hypothetically asking? The idea of draining the fuel bowls sound more inline with Japanese workings, the principle of " pay attention !!! Remember motorcycle verrrrrrrry heaven!!!!"
Cheers
Neil
Quote from: NJona86FJ on September 26, 2013, 02:55:43 AM
:hi: oh and just asking but if the ignition cut on 2cylinders would this not have potential to destroy engines? Hypothetically asking? The idea of draining the fuel bowls sound more inline with Japanese workings, the principle of " pay attention !!! Remember motorcycle verrrrrrrry heaven!!!!"
Cheers
Neil
It would certainly seem more logical...and beter for an engine to just cut the fuel when the bike is low on fuel...either by an old school dual-height petcock, an electric fuel pump cut-off or a petcock selonoid. ...but then there's that pesky article early on in the FJ days that claims they *intentionally* misfire a couple of cylinders to get the job done. :scratch_one-s_head:
I'm inclined to put the late model FJ issue to rest tomorrow by throwing a multimeter on the fuel pump and simulating a fuel-low situatiuon.
Cap'n Ron. . .
Quote from: NJona86FJ on September 26, 2013, 02:55:43 AM
:hi: oh and just asking but if the ignition cut on 2cylinders would this not have potential to destroy engines?
Cheers
Neil
No
Cancelling cylinders by the cdi is much better than running the engine lean.
I can tell by the seat of my pants feel, the fact the engine will stumble on left corners and not on rights, it is spark and not fuel.
There is no way to cancel the pump, run the bowls dry and fill them up that fast.
I believe the "reserve" system has all to do with the cdi because Yamaha would not like to have to warranty a bunch of engines because they leaned they ran them out of fuel to "remind" the rider he is low in the tank.
Randy - RPM
:hi: all good. The whole issue is interesting although mine doesn't do what's described I'd be interested to find out. Mine just stops when it's empty, yes your right randy it sucks runnin em dry.
Hi,
I have a 93 FJ and when the low fuel light comes the fuel pump does not switch off.
Mark
Quote from: racerrad8 on September 26, 2013, 03:14:43 AM
Cancelling cylinders by the cdi is much better than running the engine lean.
I can tell by the seat of my pants feel, the fact the engine will stumble on left corners and not on rights, it is spark and not fuel.
There is no way to cancel the pump, run the bowls dry and fill them up that fast.
I believe the "reserve" system has all to do with the cdi because Yamaha would not like to have to warranty a bunch of engines because they leaned they ran them out of fuel to "remind" the rider he is low in the tank.
Randy - RPM
Motorcycle manufactures have been cutting the fuel by various means for years. Most notably by the old dual-height petcock system with no lean burn conditions causing any problems that I am aware of ? :morning1: I rode them for many, many years... Even had an old 56 VW with a fuel lever to switch to reserve, gravity feed.
In the 88-93 bikes if you got a fuel cut out signal and made a left hand turn you would throw or cause the fuel level to lower on the right side which is where the sensor is located. Yes you will stumble first in a left hand turn. Sensor and fuel level is mounted on the front right side of the tank.
Still got my money on fuel not spark :rofl2:
George
Quote from: racerrad8 on September 26, 2013, 03:14:43 AM
I can tell by the seat of my pants feel, the fact the engine will stumble on left corners and not on rights, it is spark and not fuel.
Randy - RPM
I can't see how that would indicate one or the other.
Wouldn't that just be the sender unit bottoming out as the bike leans left and activating the reserve function?
Quote from: racerrad8 on September 26, 2013, 03:14:43 AM
Yamaha would not like to have to warranty a bunch of engines because they leaned they ran them out of fuel to "remind" the rider he is low in the tank.
Randy - RPM
I don't believe a 4 stroke briefly running lean under those circumstances would be an issue. It's only running lean for as long as their is sufficient fuel and spark to ignite it, which isn't very long.
If you lean out a motor with an EGT gauge, the temp rises immediately but it takes longer for that soak into the engine.
I'll still go with MY "seat of my pants" feel.
Noel
Quote from: movenon on September 26, 2013, 07:20:42 AM
.....Still got my money on fuel not spark :rofl2:
Yep, me too :good2: again, what do the wires to the 86/87 petcock do...??
Good discussion....all good points, I will learn something here....
Quote from: Pat Conlon on September 26, 2013, 11:45:15 AM
Quote from: movenon on September 26, 2013, 07:20:42 AM
.....Still got my money on fuel not spark :rofl2:
Yep, me too :good2: again, what do the wires to the 86/87 petcock do...??
Good discussion....all good points, I will learn something here....
I would start a "Poll" but I am afraid it would start another thread. :lol:
George
Quote from: ribbert on September 26, 2013, 07:29:24 AM
I can't see how that would indicate one or the other.
Wouldn't that just be the sender unit bottoming out as the bike leans left and activating the reserve function?
Yes, so the sender is sending the signal and cutting the ignition not draining fuel fuel bowls and refilling them every 100 yards while I ride in the twisties. There is not enough time to drain the carbs and refill them in that time span.
Quote from: ribbert on September 26, 2013, 07:29:24 AM
I don't believe a 4 stroke briefly running lean under those circumstances would be an issue. It's only running lean for as long as their is sufficient fuel and spark to ignite it, which isn't very long.
If you lean out a motor with an EGT gauge, the temp rises immediately but it takes longer for that soak into the engine.
I'll still go with MY "seat of my pants" feel.
Noel
Well, mine will run on the reserve function for almost 30 miles...that is a long time to be "lean" and will damage the engine. So the EGT (exhaust gas temps) rise immediately...hmmmm, I wonder if the piston also sees a immediate increase in temps...?
...But wait, the piston is aluminum and expands at twice the rate of the steel sleeve. Also, the piston is what is exposed to the leaner hotter, hotter mixture. Since the piston is the source of air movement by its up & down pumping movement, I bet it gets really hot, really fast too, maybe even faster than the exhaust. So, I think the most important part of making the engine run, gets hot pretty quick and has the opportunity to seize in the bore due to the expansion rates. I will be showing Pat his seized sleeve when he picks up his bike.
I tell you what, here is practical application test everyone can do.
I want everyone to disconnect their fuel pump. Start their bike and see just how long it takes to deplete the fuel in the carb bowls with the engine running. Then hook up the fuel pump and see how long it takes to refill them.
You will then be able to tell how much time it takes to do that with the "low reserve" function while you are riding. And if that was the case, you still have to activate the switch and you still have the required time to fill the carbs before the bike fills the carbs and rides away. But, in fact, when you activate the switch the bike instantly runs better. Maybe there is "turbo fill" to fill the carbs faster when the switch is activated, maybe the pump pressure jumps up and the pump volume increases. Oh, but wait there is still the small fuel supply hoses and needle seat orifices, maybe those expand upon the additional pressure & volume.
Think about it, do you think Yamaha made the early non fuel pump bikes cut the ignition and then change the CDI system to then cut out the fuel pump on the later models, which would require an extended amount of time to cycle the fuel bowl fuel level?
Yamaha is just like every other manufacture, keep using it as it is already developed and paid for...
If, you think that, show me the wiring schematics and a volt meter inline with your fuel pump showing the "reserve" function working and the fuel pump with no voltage.
All you have to do is bring the tech and prove it to me otherwise.
Randy - RPM
Remember, you don't need to run the bowls dry, when the bike is running on the needles the fuel level needs to drop just to a point below the mains before studdering begins.
Why don't you just disconnect the fuel line and run it into a bucket, and energize the wires going to the petcock and see what it does to the flow of fuel?
Mine works on both my 86 and 89, and yes I was very glad to find out they did work, as was my wife. :dash2:
Bob W
Quote from: Pat Conlon on September 26, 2013, 01:12:14 PM
Remember, you don't need to run the bowls dry, when the bike is running on the needles the fuel level needs to drop just to a point below the mains before studdering begins.
Dry, empty whatever you want to call it...
The distance from the bottom of the main jet to the bottom of the bowl is about 6mm, so while they are not dry or empty, there is only the well of fuel in the bottom of the bowl when the main jet becomes uncovered...
Might as well be empty...
Randy - RPM
Quote from: Pat Conlon on September 26, 2013, 01:12:14 PM
Remember, you don't need to run the bowls dry, when the bike is running on the needles the fuel level needs to drop just to a point below the mains before studdering begins.
If you're just cruising, then you only need to uncover the idle jet to feel the engine surging. I had a tank vent problem once and went a few miles as the carbs ran out of fuel. Once I noticed the slight surging, I twisted the throttle and the engine picked back up as it transitioned from the idle circuit (which was starving for fuel) to the main jet and needle (which still had fuel).
I'm not sure what's at work with the reserve, but I've run on 2 cylinders before and it is a VERY noticeable change in engine response and exhaust note. I do recall that the low fuel light works as a variable resistor circuit, which is why the light changes intensity as the fuel level gets lower. The sensing element has a current running through it when the ignition is on. When surrounded by fuel, the circuit stays cool and has a certain resistance which keeps the fuel light off. As the fuel level drops and the element begins to be uncovered, it heats up and the resistance changes causing the fuel light to begin to glow. The more the resistance changes, the brighter the light gets. When I first heard this circuit description, I remember thinking that it can't be a good idea. The only place I want to mix fuel and electricity is in the combustion chamber!
Quote from: FJ_Hooligan on September 26, 2013, 02:50:18 PM
I'm not sure what's at work with the reserve, I do recall that the low fuel light works as a variable resistor circuit, which is why the light changes intensity as the fuel level gets lower. The sensing element has a current running through it when the ignition is on. When surrounded by fuel, the circuit stays cool and has a certain resistance which keeps the fuel light off. As the fuel level drops and the element begins to be uncovered, it heats up and the resistance changes causing the fuel light to begin to glow. The more the resistance changes, the brighter the light gets.
The highlighted above is interesting.
I just went out to the garage to take some voltage readings off the fuel pump in several different states. My bike is a '92 with ABS. The ABS light is where everyone else has their low fuel light, so I don't (believe) I have any dash indication of low fuel. The fuel tank is currently at about 1/4 full.
I put the multimeter probes into the fuel pump wiring harness connector alongside the wires without disconnecting it from the wiring harness. I verified that the probes were making contact by switching the ignition on and off again. I'm using "12V" below to indicate full power even though voltage readings would vary +-a volt or two.
Reserve switch in ON positionEngine off, key off: 0V
Engine off, key on: 12V for 5 seconds then 0V
Engine on, key on: 12V
All the above makes sense and is behaving as I would expect. I then attempted to simulate a low-fuel condition by depressing the float on the level sender down to the bottom of the tank with a 2' length of PVC pipe. The PVC was just heavy enough to hold the float level sender at the bottom of the tank for as long as I wanted.
The fuel gauge dropped well past empty, but did not reach the stop pin.
There was no light indication on the dash of a low fuel state (ABS model)
The engine continued to run at 1,100 RPM smoothly
The fuel pump continued to run with 12V indicated on the multimeter
I let this run in this way for ten minutes with no change. Pump still had 12V, engine ran normally.
I then flipped the tank switch to RES with no change.
In short, either the reserve function is no longer working on my bike, or I'm not able to simulate a low fuel condition just by lowering the level sender float. Possibly due to what FJ_Hooligan stated above.
If someone can verify that I'd have to drain the tank to simulate the low fuel condition, I'd be happy to go try that.
Cap'n Ron. . .
I don't think reserve is triggered by the float position. That's too variable, the pump (or whatever) would be cutting on and off like mad as the fuel sloshed around. Damping in the fuel gauge (assuming you still have damping in the fuel gauge) prevents the gauge from jumping around.
I had an old Yamaha with a low fuel light that drove me crazy when the tank got low. I'm pretty sure it was activated by the float. It would light up and I would reach up and push a button to cancel it only to have it come back on after the fuel sloshed around a little. I eventually jumpered that sensor.
I think the FJ reserve function gets its signal from the low fuel circuit. Even though that light is missing from the ABS models
Quote from: Capn Ron on September 26, 2013, 03:57:59 PM
Quote from: FJ_Hooligan on September 26, 2013, 02:50:18 PM
I'm not sure what's at work with the reserve, I do recall that the low fuel light works as a variable resistor circuit, which is why the light changes intensity as the fuel level gets lower. The sensing element has a current running through it when the ignition is on. When surrounded by fuel, the circuit stays cool and has a certain resistance which keeps the fuel light off. As the fuel level drops and the element begins to be uncovered, it heats up and the resistance changes causing the fuel light to begin to glow. The more the resistance changes, the brighter the light gets.
The highlighted above is interesting.
I just went out to the garage to take some voltage readings off the fuel pump in several different states. My bike is a '92 with ABS. The ABS light is where everyone else has their low fuel light, so I don't (believe) I have any dash indication of low fuel. The fuel tank is currently at about 1/4 full.
I put the multimeter probes into the fuel pump wiring harness connector alongside the wires without disconnecting it from the wiring harness. I verified that the probes were making contact by switching the ignition on and off again. I'm using "12V" below to indicate full power even though voltage readings would vary +-a volt or two.
Reserve switch in ON position
Engine off, key off: 0V
Engine off, key on: 12V for 5 seconds then 0V
Engine on, key on: 12V
All the above makes sense and is behaving as I would expect. I then attempted to simulate a low-fuel condition by depressing the float on the level sender down to the bottom of the tank with a 2' length of PVC pipe. The PVC was just heavy enough to hold the float level sender at the bottom of the tank for as long as I wanted.
The fuel gauge dropped well past empty, but did not reach the stop pin.
There was no light indication on the dash of a low fuel state (ABS model)
The engine continued to run at 1,100 RPM smoothly
The fuel pump continued to run with 12V indicated on the multimeter
I let this run in this way for ten minutes with no change. Pump still had 12V, engine ran normally.
I then flipped the tank switch to RES with no change.
In short, either the reserve function is no longer working on my bike, or I'm not able to simulate a low fuel condition just by lowering the level sender float. Possibly due to what FJ_Hooligan stated above.
If someone can verify that I'd have to drain the tank to simulate the low fuel condition, I'd be happy to go try that.
Cap'n Ron. . .
The sensor doesn't move with the float. It is in a fixed position. I will try to get you a picture in a few min. :good2:
George
Quote from: movenon on September 26, 2013, 05:31:38 PM
The sensor doesn't move with the float. It is in a fixed position. I will try to get you a picture in a few min. :good2:
George
Perfect George! Also, can you verify that it's
not a mechanical switch of any sort and is more like a thermal sensor as FJ_Hooligan suggests?
Cap'n Ron. . .
The thought of a thermal sensor in a enclosed steel shell with fuel......makes me nervous.
I think I'll stop reading now......
(http://)
Quote from: Capn Ron on September 26, 2013, 05:39:38 PM
Quote from: movenon on September 26, 2013, 05:31:38 PM
The sensor doesn't move with the float. It is in a fixed position. I will try to get you a picture in a few min. :good2:
George
Perfect George! Also, can you verify that it's not a mechanical switch of any sort and is more like a thermal sensor as FJ_Hooligan suggests?
Cap'n Ron. . .
(http://fjowners.com/gallery/5/1651_26_09_13_4_44_58.jpeg)
(http://fjowners.com/gallery/5/1651_26_09_13_4_45_57.jpeg)
(http://fjowners.com/gallery/5/1651_26_09_13_4_47_22.jpeg)
Kind of a cruddy unit but that's what it is in my 1990.
George
Quote from: Pat Conlon on September 26, 2013, 05:47:58 PM
The thought of a thermal sensor in a enclosed steel shell with fuel......makes me nervous.
I think I'll stop reading now......
What about all the cars, and probably some bikes, that have in tank electric fuel pumps?
This is a 1991 wiring diagram showing what I am looking at. Sorry it's not the best photo. I also forgot to highlight the reserve switch. :dash2:
(http://fjowners.com/gallery/5/1651_26_09_13_5_05_19.jpeg)
George
Good stuff George! Now that I know what I'm looking for, I poked a flashlight into my tank and I can see that entire sensor is completely submerged in fuel. I'll drain some fuel out of the tank until that sensor is hanging in open air...and redo my tests.
Doesn't look like your wiring schematic came through...Might be helpful!
Cap'n Ron. . .
Quote from: FJ_Hooligan on September 26, 2013, 02:50:18 PM
When surrounded by fuel, the circuit stays cool and has a certain resistance which keeps the fuel light off. As the fuel level drops and the element begins to be uncovered, it heats up
What about when the fuel tank (and fuel) gets so hot you can hardly touch it?
Quote from: racerrad8 on September 26, 2013, 12:41:09 PM
Well, mine will run on the reserve function for almost 30 miles...that is a long time to be "lean" and will damage the engine. So the EGT (exhaust gas temps) rise immediately...
It's only running lean from when it starts to splutter to when you switch to reserve, at which point normal operation is restored.
I don't know why everyone's making such a meal of this, it's simple enough to check, and I just have.
My bike happens to only have a cupful of fuel in it and has been on reserve for a few days.
I just started it on the side stand, switched it back to main, waited for it to splutter, probed the live wire to the pump, nothing. While holding the test light on the terminal, switched to reserve, light immediately comes on, power restored to pump.
Repeat cycle 3 times, same results.
Noel
Quote from: ribbert on September 26, 2013, 06:28:04 PM
Quote from: FJ_Hooligan on September 26, 2013, 02:50:18 PM
When surrounded by fuel, the circuit stays cool and has a certain resistance which keeps the fuel light off. As the fuel level drops and the element begins to be uncovered, it heats up
What about when the fuel tank (and fuel) gets so hot you can hardly touch it?
Quote from: racerrad8 on September 26, 2013, 12:41:09 PM
Well, mine will run on the reserve function for almost 30 miles...that is a long time to be "lean" and will damage the engine. So the EGT (exhaust gas temps) rise immediately...
It's only running lean from when it starts to splutter to when you switch to reserve, at which point normal operation is restored.
I don't know why everyone's making such a meal of this, it's simple enough to check, and I just have.
My bike happens to only have a cupful of fuel in it and has been on reserve for a few days.
I just started it on the side stand, switched it back to main, waited for it to splutter, probed the live wire to the pump, nothing. While holding the test light on the terminal, switched to reserve, light immediately comes on, power restored to pump.
Repeat cycle 3 times, same results.
Noel
:good2: :good2: :dance2:
Ron, diagram should show.
George
Quote from: NJona86FJ on September 26, 2013, 02:50:25 AM
G'day
Ok my fuel light is on the dash on the LH side between the speedo and tachometer,up high but below the neutral and turn signal. It gets brighter the less I have, and you can make it go out by stopping hardish. I have ridden it too empty a few times without flipping the reserve switch. I honestly think it makes no difference on my bike. Know this for certain as I have a reserve switch no more. I am losing fuel though, not sure all this talk of fuel systems makes me think its time to have a bo peep in there maybe replace a few odd hoses. ( this will possibly be another thread)
Just to throw a spanner in the works. :hi:
Cheers
Neil
Something is likely broken, or disabled, in the reserve circuit....
Quote from: movenon on September 26, 2013, 12:38:00 PM
Quote from: Pat Conlon on September 26, 2013, 11:45:15 AM
Quote from: movenon on September 26, 2013, 07:20:42 AM
.....Still got my money on fuel not spark :rofl2:
Yep, me too :good2: again, what do the wires to the 86/87 petcock do...??
Good discussion....all good points, I will learn something here....
I would start a "Poll" but I am afraid it would start another thread. :lol:
George
Opinions mean NOTHING, they won't change the facts.... I'll write a note to myself to look this up in the manual, pretty sure it explains how these work. I'll check it this weekend, unless someone here beats me to it...
I'm pretty sure Yamaha wanted to make it feel like everyone grew up with, meaning, the dual-height fuel inlets on manual petcocks.
ETA: Looks like Noel just proved it's a FUEL-cut, not spark, for the pump-equipped models...
Quote from: movenon on September 26, 2013, 06:08:52 PM
(http://fjowners.com/gallery/5/1651_26_09_13_5_05_19.jpeg)
Hmmm, by looking at his wiring diagram the "reserve" switch is not part of the fuel pump system, it is part of the CDI.
Quote from: RichBaker on September 26, 2013, 07:25:46 PM
ETA: Looks like Noel just proved it's a FUEL-cut, not spark, for the pump-equipped models...
What proof...?
I see no video of the running bike showing the stated results.
I am awaiting proof.
Randy - RPM
Quote from: movenon on September 26, 2013, 06:08:52 PM
(http://fjowners.com/gallery/5/1651_26_09_13_5_05_19.jpeg)
My read of this is wire "G" provides output of the low fuel thermal sender to cdi. The "Reserve Switch" restores power to the "Fuel Pump" relay, closing the switch and powering the pump. The only thing that's not clear is how the fuel pump relay is powered when the reserve switch is open and G says there's enough fuel, but I'd bet the normal signal on G causes cdi to close the relay with the other wire out of the top of the cdi going hot, the one with the writing by it.
In other words, it is cutting the fuel pump relay it looks like. But notice that the cdi is also controlling the coils... maybe it cuts spark and fuel, then you restore normal ops pretty quickly by flipping the reserve switch. If you don't flip the switch, you'll run the bowls dry on 2 cyl and it should die.
There's a test for you guys with working reserve switches...
Frank
The other half of the drawing explains more. The top 2 wires going off to the left, one from the relay coil and the R/W line go on past the engine kill switch and merge as one wire going to the ignition fuse. The kill switch is in the bottom line.
The diagram is in the 1991 FJ 1200 Service Guide.
Just a curious note. I keep seeing a pattern. Any wire with Green "G" on it has to do with the fuel circuit, any wire that has Blue "L" on it is a control line. Any wire with Red "R" in it carry's B+, Gray "Gy" signal line, and Black of course is usually ground.
Then there seems to be a priority order of things.
Red
Red / White
Brown / Red
Red / Yellow
note the fuel reserve switch is R/G, red for b+ and green for fuel related. Trivia... :wacko3:
I see a few deviations of this but in general the above seems to be true.
Frank, you might be correct on both happening. :morning2: More testing required. I am still in the fuel cut off only camp. I just do not believe Yamaha made it all that complicated. When it comes to what really happens in the CDI units all the manufactures keep that a big secret. They will not even tell you the theory of operation or pin read outs.
I uploaded the 91 Service Guide into rapidshare.com https://rapidshare.com/home (https://rapidshare.com/home) You can log in as name: movenon and download it.
Password: fjowner
George
I drained out all but about 1/2 gallon of fuel to try and back Noel up on this one...The fuel was well below that sensor and with the tank switch in the "ON" position, the bike just keeps running. I suspect that I don't really have a working reserve warning system, so It looks like I'm out of this debate. At least as far as absolute testing results are concerned.
To me, the reserve switch in the schematic looks like it just has a hot lead and is normally open, when you close the circuit, it just sends a + voltage signal into the ignitor. That ignitor is an amalgam of circuits, IC chips, and a pile of If-then-else logic (Randy is familiar with how I know that :biggrin: ). I'd be hard pressed to know what that signal does to any down-the-line outputs from the ignitor. It may very well cut the voltage to the fuel pump (on models so equipped)...it may *also* cause a misfire as reported in magazine articles early on.
I REALLY wish mine functioned as it's supposed to, because, as Noel suggests, I'd have the answer in 10 minutes.
To answer your question Noel as to why folks are making such a meal of this (I loved that)...I tore my bike apart to solve a starting issue when I was on my trip, 3,000 miles from home. I began at one end of the bike testing each function as I understood them to work and ended up at the other three days later. I cleaned wires/connectors, replaced switches, installed relays in an effort to troubleshoot the problem. Understanding...REALLY understanding how a system works makes troubleshooting that system a snap. At least that's my excuse for wanting to know. :biggrin:
Cap'n Ron. . .
In another thread about water and FJ's I was thinking that the fuel reserve switch doesn't appear to be real water proof and is in a vulnerable position.
On my bike with the new fairing there looks to be a small "leak" point around the front turn signal buckets. An entry point for water in a rain storm. I might be missing a seal there ? It's on my list of things to investagate.... :dash2:
George
Quote from: Flynt on September 26, 2013, 09:34:31 PM
Quote from: movenon on September 26, 2013, 06:08:52 PM
(http://fjowners.com/gallery/5/1651_26_09_13_5_05_19.jpeg)
My read of this is wire "G" provides output of the low fuel thermal sender to cdi. The "Reserve Switch" restores power to the "Fuel Pump" relay, closing the switch and powering the pump. The only thing that's not clear is how the fuel pump relay is powered when the reserve switch is open and G says there's enough fuel, but I'd bet the normal signal on G causes cdi to close the relay with the other wire out of the top of the cdi going hot, the one with the writing by it.
In other words, it is cutting the fuel pump relay it looks like. But notice that the cdi is also controlling the coils... maybe it cuts spark and fuel, then you restore normal ops pretty quickly by flipping the reserve switch. If you don't flip the switch, you'll run the bowls dry on 2 cyl and it should die.
There's a test for you guys with working reserve switches...
Frank
It goes thru the ignitor because it has to see the engine running for the fuel pump to keep pumping.... If no "engine running" signal, the fuel pump shuts off after 5 seconds.
Quoteper Noel's post above: "My bike happens to only have a cupful of fuel in it and has been on reserve for a few days.
I just started it on the side stand, switched it back to main, waited for it to splutter, probed the live wire to the pump, nothing. While holding the test light on the terminal, switched to reserve, light immediately comes on, power restored to pump.
Repeat cycle 3 times, same results.
Noel
I'd say that's proof.....
Quote from: movenon on September 26, 2013, 10:48:18 PM
In another thread about water and FJ's I was thinking that the fuel reserve switch doesn't appear to be real water proof and is in a vulnerable position.
On my bike with the new fairing there looks to be a small "leak" point around the front turn signal buckets. An entry point for water in a rain storm. I might be missing a seal there ? It's on my list of things to investagate.... :dash2:
George
Oh, yeah...water will find it's way into about anywhere and that rocker switch is no exception. Thing is, 12V DC isn't going to do any harm to a switch when water is introduced or cause a connection to be made. You can drop + and - battery leads into a glass of water and you won't see even a .01V drop on the battery. Turns out at the low voltages we're dealing with, water is a terrible conductor. Don't take the same chance with 400 amp, 408V AC mains!!
The bigger issue is corrosion and there's where water will slowly...quietly...corrode your contacts in the background to the point where they have a very high resistance to conducting currrent. That resistance can cause heat...arcing...and more corrosion. Eventually, the corrosion is an insulator and the switch no longer works.
Don't get me started on battling salt water corrosion on the sailboat! :ireful:
Cap'n Ron. . .
OK......I'm of 2 minds now - mainly due to not knowing what goes on in the Ignitor box (which is no longer even a consideration on my bike seeing as its no longer connected to the loom).
Looking at the coloured wiring diagram for FJ1200B ('91) included in my Yamaha Service manual, the Green/Red stripe wire comes from the fuel level sensor and goes to 3 locations - the lowfuel light, the Relay assembly and the Digital Ignitor Unit.
Fuel pump power is a blue/black stripe wire from the relay assembly
Reserve switch has 2 wires - a Red/blue stripe which goes to the Digital Ignitor, and a Red/Black stripe which goes to 3 places - the Engine Stop switch, the Relay Assembly and the Digital Ignitor.
In all of the above, - any wire going to the ignitor no longer comes into the equation.
Now on my bike, If I leave the reserve switch in the normal on position, the fuel pump does not run - period, and if i switch from the Res position to the On position while riding, it will run until the bowls are low on fuel and then start to splutter. Switch it to the Res position and it will return to full power within 10 seconds or so (not instantaneous) ...... that's why I think the reserve switch acts on the fuel pump, not the ignition. If the Ignitor box was still in the circuit, then it could be a timed ignition shutdown, but its not!
That's my take on it.
Harvy
Quote from: racerrad8 on September 26, 2013, 09:05:58 PM
What proof...?
I see no video of the running bike showing the stated results.
I am awaiting proof.
Randy - RPM
You'll be waiting a while, there won't be one. I conducted that test for my benefit because while confident of the outcome it removed that niggling 1%, and then, only because it was easy. If my bike had more fuel in it I wouldn't have even bothered.
I only posted my findings because of all the speculation that was going on and thought it might be of interest. People can draw their own conclusions from those findings. I didn't make any claims, I simply posted my observations. There is nothing for me to
prove.
My views on mechanical issues and procedures are not always embraced here. If some wish to dismiss it on the basis that it came from me, fine. If they think I skipped the lesson at trade school on how to tell if a test light is glowing or not, fine. If they choose to suggest it didn't happen, not so fine.
You want proof? you'll have to look elsewhere. It's a bit sad If you are only prepared to believe what I say if it is corroborated by video. After all, we are only talking about a test light going on and off.
I've never seen a demand for information you have posted to be verified in such a manner.
Noel
Well gee whiz. I'm glad I'm not the only one that gets this neurotic about this stuff.
I'll do my own investigation, but looking at the wiring diagram I'd say it's pretty conclusive that it's the pump that's getting de-energized.
Looking at that I'd say it would be pretty cool to measure what the value of the resistor north of the tank sensor is. You could add a pot and adjust where your reserve is.
If you're like me and find yourself often 60+miles from a fuel depot then it's a nice idea. On the same note, characterizing the fuel level sensor would be nice to see if it's possible to add resistance to calibrate it into a more useful range. (Or if it uses discrete components change a resistor)
Cool stuff... (popcorn)
mmmm...I wouldn`t call it thermal sensing.....This might help explain: How Capacitive Liquid Level Sensors Work (http://www.youtube.com/watch?v=0du-QU1Q0T4#ws)
Looks to me to be a reed switch. They are commonly used in hazzardous and explosive environments...gas tanks.
Scott
Quote from: ribbert on September 26, 2013, 06:28:04 PM
I just started it on the side stand, switched it back to main, waited for it to splutter, probed the live wire to the pump, nothing. While holding the test light on the terminal, switched to reserve, light immediately comes on, power restored to pump.
Repeat cycle 3 times, same results.
Noel
But what about the running, did the sputtering go away instantly or did it take time to refill the fuel bowls?
Proof; A video would have answered that question.
Noel, I am glad you were able to add your observations, but it still does not answer the question. If your observations answered the question and the video supported your observations, then we could all rest easier know that the mystery had been resolved.
No video, that's fine I am confident in your ability to see if your test light illuminates or not and the understanding of electrical function. But the fact remains, the reserve switch does not appear to function solely within the fuel system.
The reason a video would be nice so that it could be
"proved" that the fuel pump does not run, the engine is stumbling and as soon as you switch the switch the engine runs fine or not. As I posted earlier in the thread, how does the fuel pump fill the carbs "instantly" to allow the engine to run fine?
Heck, even Harvy has posted that it takes 10 seconds for his engine to start running properly when low on fuel as he does not use the stock CDI and does not have the ignition cut out circuit.
Quote from: Harvy on September 26, 2013, 11:32:16 PM
...Switch it to the Res position and it will return to full power within 10 seconds or so (not instantaneous)...
Harvy
So, that means it has to fill the carbs up for it to run properly when the stock CDI is removed from the equation. But everyone else says as soon as they switch the reserve switch the bike run fine instantly, at the flip of the switch.
Maybe I am confused, maybe something has been lost in the translation of language. :unknown:
Doesn't that mean the CDI box is affecting the spark cycle somehow and cutting out the fuel pump?
When the switch is activated, the CDI then allows full spark and the fuel re-energizes filling the carbs again?
Or...Harvy, maybe when you changed over to the aftermarket ignition you lost your "turbo fill" ability of the fuel pump when the reserve switch is activated allow the engine to return to the proper running cycle instantly.
Quote from: ribbert on September 27, 2013, 06:51:24 AM
I conducted that test for my benefit because while confident of the outcome it removed that niggling 1%, and then, only because it was easy.
I only posted my findings because of all the speculation that was going on and thought it might be of interest. People can draw their own conclusions from those findings. I didn't make any claims, I simply posted my observations. There is nothing for me to prove.
My views on mechanical issues and procedures are not always embraced here. If some wish to dismiss it on the basis that it came from me, fine. If they think I skipped the lesson at trade school on how to tell if a test light is glowing or not, fine. If they choose to suggest it didn't happen, not so fine.
You want proof? you'll have to look elsewhere. It's a bit sad If you are only prepared to believe what I say if it is corroborated by video. After all, we are only talking about a test light going on and off.
I've never seen a demand for information you have posted to be verified in such a manner.
Noel
I am not going to be awaiting your proof, as you are not offering it. But, just like you questioned my comments earlier about the system working in the CDI as there is not enough time for the carbs to refill and you cannot understand how I can determine the feel of the ignition system cut out compared to out of gas, I can't imaging with all of your experience you cannot tell the difference between the two. The rumble/sputtering of the ignition system compared to the carbs being out of fuel. They feel very different, at least to my experience and seat of the pants feel. I can tell you specifically if your are having an ignition problem or fuel problem and I do not need a test light to know.
I am sorry that you fell I have questioned your authority, skill level or personal knowledge on this matter, it is not intended to question your ability, but you have posted incomplete finding on the topic and it looks like it struck a nerve; maybe not but it does to me.
Sometimes you have to take your own advice;
Quote from: ribbert on August 17, 2013, 07:52:34 PM
I don't know why you even bought into this.
And:
Quote from: ribbert on August 17, 2013, 07:52:34 PM
If the extent of what has been said is what was posted this morning, I can't possibly see what your pissed at.
I am not demanding proof of your findings, do what you want, but proof will support your position when you make your observations as you posted them to end the speculation.
So, the question still remains...
CDI interrupt?
Fuel Pump interrupt?
Or a combination of both?
Based on Noel's observations, it seems part of the question has been answered; thank you Noel.
But as far as the rest of the question, as I stated earlier...
Quote from: racerrad8 on September 26, 2013, 12:41:09 PM
All you have to do is bring the tech and prove it to me otherwise.
After all this is the "digital campfire" where we can all learn something.
Randy - RPM
I would explain this with my previous observation. In typical cruising, starving the idle circuit will cause noticeable stumbling. I think a possible explanation is when someone feels that stumble and flips the reserve switch (assuming it is working ocrrectly), they then roll back into the throttle and start getting fuel from the main jet and needle circuit which would appear to be an instantaneous fix. In this case, the fuel pump would catch up unnoticed.
Quote from: FJ_Hooligan on September 27, 2013, 04:12:36 PM
I would explain this with my previous observation. In typical cruising, starving the idle circuit will cause noticeable stumbling. I think a possible explanation is when someone feels that stumble and flips the reserve switch (assuming it is working ocrrectly), they then roll back into the throttle and start getting fuel from the main jet and needle circuit which would appear to be an instanteous fix. In this case, the fuel pump would catch up unnoticed.
So if I read the explanation correctly, if they do not flip the reserve switch or it malfunctions the fuel pump does not turn on and the bike runs out of fuel?
It will be interesting to see how long you can ride, without turning on the reserve before the bike dies. It would also be interesting to open a bowl drain and see how much fuel is actually in the bowl in comparison to the normal as controlled by the float level.
Randy - RPM
Quote from: racerrad8 on September 27, 2013, 04:33:54 PM
So if I read the explanation correctly, if they do not flip the reserve switch or it malfunctions the fuel pump does not turn on and the bike runs out of fuel?
Yep, it happened to my buddy Paul....the first time he rode my '92.
I forgot to tell him about the reserve switch. He was riding in front, the bike started sputtering, he slowed down thinking something was wrong and ended up stopped by the side of the road with a dead engine.
His comment was "shit the fuel light just came on...that's not much of a warning.."
Flipped the switch to 'R' ....the fuel pump started clicking....and away we went.
I totally forgot about the switch because my '84 does not have one....
Quote from: Pat Conlon on September 27, 2013, 06:52:50 PM
Quote from: racerrad8 on September 27, 2013, 04:33:54 PM
So if I read the explanation correctly, if they do not flip the reserve switch or it malfunctions the fuel pump does not turn on and the bike runs out of fuel?
Yep, it happened to my buddy Paul....the first time he rode my '92.
I forgot to tell him about the reserve switch. He was riding in front, the bike started sputtering, he slowed down thinking something was wrong and ended up stopped by the side of the road with a dead engine.
His comment was "shit the fuel light just came on...that's not much of a warning.."
Flipped the switch to 'R' ....the fuel pump started clicking....and away we went.
I totally forgot about the switch because my '84 does not have one....
See, more proof.... Its the fuel not the igntior doing some cosmic miss fire of two cylinders.. The bowls do not have to be dry to cause a miss fire, probably more accurately a rough running condition leading to fuel starvation thus leading to profanity.... :biggrin:
George :good2: :lol:
Quote from: racerrad8 on September 27, 2013, 04:33:54 PM
So if I read the explanation correctly, if they do not flip the reserve switch or it malfunctions the fuel pump does not turn on and the bike runs out of fuel?
It will be interesting to see how long you can ride, without turning on the reserve before the bike dies. It would also be interesting to open a bowl drain and see how much fuel is actually in the bowl in comparison to the normal as controlled by the float level.
My experience was a tank venting problem, so I can't vouch that the reserve function works the same way. I was able to go about 3 miles. I recall feeling the engine start to struggle. I had gotten caught in the rain and thought maybe a coil had gotten wet. When I felt the stumble, I thought I would just open it up and drive through it by heating the coil up and drying it off. At first It thought it was working because when I rolled on the throttle, the motor picked back up and everything seemed fine. For about 1/2 of a mile when the stumble returned and quickly followed by the engine totally dying. I pulled in the clutch and coasted as far as I could before pulling to the side of the road.
About 10 minutes of confused troubleshooting before I discovered the venting problem.
Quote from: FJ_Hooligan on September 27, 2013, 08:48:24 PM
Quote from: racerrad8 on September 27, 2013, 04:33:54 PM
So if I read the explanation correctly, if they do not flip the reserve switch or it malfunctions the fuel pump does not turn on and the bike runs out of fuel?
It will be interesting to see how long you can ride, without turning on the reserve before the bike dies. It would also be interesting to open a bowl drain and see how much fuel is actually in the bowl in comparison to the normal as controlled by the float level.
My experience was a tank venting problem, so I can't vouch that the reserve function works the same way. I was able to go about 3 miles. I recall feeling the engine start to struggle. I had gotten caught in the rain and thought maybe a coil had gotten wet. When I felt the stumble, I thought I would just open it up and drive through it by heating the coil up and drying it off. At first It thought it was working because when I rolled on the throttle, the motor picked back up and everything seemed fine. For about 1/2 of a mile when the stumble returned and quickly followed by the engine totally dying. I pulled in the clutch and coasted as far as I could before pulling to the side of the road.
About 10 minutes of confused troubleshooting before I discovered the venting problem.
Yea, they should put a notice decal on the fuel cap "in case of engine failer open cap" :lol:
George
Howdy everyone,
Well, while Mr. Conlon's statement implies the fuel pump is involved in the operation of the reserve switch it does not disprove that the CDI unit is not canceling out the ignition as well.
If I may state my experience, which while it may not be conclusive to this discussion, it may have some merit.
I have an auxiliary fuel tank that I have plumbed through a fuel transfer valve which in turn leads to the fuel pump.
As I run the auxiliary tank dry, without involving the CDI unit or fuel pump shut off in any way, the engine stumbles and misses, prompting me to transfer to the main tank and there is a delay before the engine is up and running again.
Now, running on the main tank as I go on reserve the engine again begins to miss but it seems to be just that, an engine misfiring, not running out of fuel, AND it is noticeably different from when the auxiliary tank runs dry. And when switched to the reserve (on the main tank) and the engine resumes its' normal cadence, it is noticeably different and quicker than when the engine has actually run out of fuel.
So for what it is worth, that is my experience with the reserve switch.
Now on to a perhaps a touchy subject re: verification of statements. While not part of this subject, it was brought up by another and in my opinion is not correct.
"I've never seen a demand for information you have posted to be verified in such a manner."
Actually, any claim made by the gentleman from RPM is indeed subject to verification; by all of those who purchase the various products offered by RPM; both official Yamaha parts and FJ specific items developed specifically for the FJ's.
Ride safe,
Mike Ramos.
That's a interesting point Mike....
In absence of conclusive bench testing on the fuel pump models...Let's talk about the 86/87 reserve switch function....
Hey Randy, I have an idea....Can you take one of your new 86/87 petcocks and hook it up to a 12v source and see if you can blow thru it?
We know vacuum opens/closes the petcock, and I suspect a 12v signal closes it...
Or...if the reserve interrupt on the '86/87 was ignition, then folks who have changed over to the straight vacuum 84/85 petcock would still have the ignition interrupt feature, correct?
I wonder if our Red Power Ranger noticed this?
Can anyone post a wiring diagram for the '86/87s?
Quote from: Pat Conlon on September 27, 2013, 09:26:50 PM
Hey Randy, I have an idea....Can you take one of your new 86/87 petcocks and hook it up to a 12v source and see if you can blow thru it?
We know vacuum opens/closes the petcock, and I suspect a 12v signal closes it...
I wondered this as well...In a gravity feed fuel system, to stop the fuel from flooding the cylinders and working its way into the crankcase (experienced this day ONE on my Seca 550), the needles and seats are the only defense. Because of this, whenever you stored your bike, you were supposed to turn the fuel tank petcock to "OFF".
Fast forward to the fuel pump late model FJs...The fuel pump itself will stop the flow of fuel *before* the carburetors by doing nothing more than shutting the bike down via the ignition key.
Somewhere in the middle...86/87 there was a more expensive petcock used with a wired connection. I wondered if this was a stop-gap solution to the fuel flooding problem before the fuel pump solution was implimented. I'm pondering if the 86/87 petcock NEEDS a 12V signal to flow fuel...therby cutting the fuel supply when the bike is parked to solve the problem of filling the cylinders/crankcase with gasoline if the needles and seats are leaking.
Pat above says that it opens via vacuum pressure...so what exactly is happening with the electrical connection?
Cap'n Ron. . .
Ron, the opening and closing of 86/87 petcock is done by engine vacuum taken off the #2 intake manifold.
As in, when vacuum is present (engine starting or running) the petcock opens...and gas flows. When the vacuum stops, (engine off) the petcock closes.
No worries about flooding the engine....when all is working correctly...
I suspect the wires going to the '86/87 petcock are to activate a electric solenoid which closes the petcock (even when the vacuum signal is present) This happens when the low fuel sensor in the tank sends the signal to the petcock.
Flip the reserve switch to reserve and the electrical signal stops and the solenoid opens up and gas starts flowing again...
My theory anyway....I don't have a '86/87 .....so I'm just guessing. :flag_of_truce:
Hooking up a power source to the '86/87 petcock would be interesting. You would need to also provide a vacuum signal to the petcock to hold it in the open position, while you checked to see if the solenoid closed off the flow.
Ahhhh...I gotcha Pat. The vacuum tap opens the petcock to allow fuel to flow. If the engine isn't running, the fuel can't overwhelm the carbs/cylinders. Simple enough. You're wondering if the electrical part of the '86/'87 petcock is an override. Shutting down the fuel supply as a response to the sensor no longer sensing fuel at its preset level even while there is vacuum present.
I'm now curious about this too... But then again...I'm a curious individual. :crazy: :wacko2:
Cap'n Ron. . .
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
Or...Harvy, maybe when you changed over to the aftermarket ignition you lost your "turbo fill" ability of the fuel pump when the reserve switch is activated allow the engine to return to the proper running cycle instantly.
So, the question still remains...
CDI interrupt?
Fuel Pump interrupt?
Or a combination of both?
After all this is the "digital campfire" where we can all learn something.
Randy - RPM
I'm not certain that its one way or the other or a combination of both. The more I'm reading here, the more I'm thinking that over the generation changes, Mr Yamaha decided to change the nature of the beast?
As to the "tubo fill", I can't really say as I don't have an OEM pump anymore either.
All I can say with certainty is that on MY '91 FJ, with an aftermarket pump and no CDI connect to the loom, the Reserve switch is controlling the fuel pump, not the ignition.
Take from that what you will folks.
Cheers
Harvy
Quote from: Mike Ramos on September 27, 2013, 09:13:26 PM
Well, while Mr. Conlon's statement implies the fuel pump is involved in the operation of the reserve switch it does not disprove that the CDI unit is not canceling out the ignition as well.
Mike Ramos.
C'mon, Both?? A secondary, redundant low fuel warning system on a motorbike?
Quote from: Mike Ramos on September 27, 2013, 09:13:26 PM
Now on to a perhaps a touchy subject re: verification of statements. While not part of this subject, it was brought up by another and in my opinion is not correct.
"I've never seen a demand for information you have posted to be verified in such a manner."
Actually, any claim made by the gentleman from RPM is indeed subject to verification; by all of those who purchase the various products offered by RPM; both official Yamaha parts and FJ specific items developed specifically for the FJ's.
Ride safe,
Mike Ramos.
Mike, you are barking up the wrong tree here. It's a poor analogy, and while I can see the connection you are trying to make it's not really relevant in this instance.
Noel
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
But what about the running, did the sputtering go away instantly or did it take time to refill the fuel bowls?
Proof; A video would have answered that question.
Noel, I am glad you were able to add your observations, but it still does not answer the question. If your observations answered the question and the video supported your observations, then we could all rest easier know that the mystery had been resolved.
This subject was raised a while back. I said at the time that I believed it was fuel because of the way it behaved, (and I have had plenty of opportunity to observe it) but beyond establishing that to my own satisfaction, I had little interest in the subject until such time as I needed to trouble shoot it.
Nothing has changed.
However, all the ongoing half arsed theories, speculation, anecdotal reports and inconclusive tests did spark enough interest (and that 1% niggle) for me to go and test it. As previously stated, only because it was easy and my bike happened to be low on fuel.
If I thought it would help someone with a problem, and no one else was prepared to do so, I would conduct the test again and video it. If it was something that only required a photo I would have posted it with my findings at the time.
A video showing what I did would be easy. A video proving I was actually doing what you were seeing would be impossible.
It would be an exercise in absurdity to think that I could video all the elements of that test in manner that would prove anything and be beyond the suggestion it was faked to someone already of that mindset.
I have my proof, I shared my findings and my ONLY ongoing interest in the subject is my credibility.
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
But everyone else says as soon as they switch the reserve switch the bike run fine instantly, at the flip of the switch.
Randy - RPM
I recall a lot of people, especially newbies, mentioning/asking about the lag
after they have switched over, as has always been the case with mine. I didn't think there was any dispute about that.
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
I can determine the feel of the ignition system cut out compared to out of gas, I can't imaging with all of your experience you cannot tell the difference between the two. The rumble/sputtering of the ignition system compared to the carbs being out of fuel. They feel very different, at least to my experience and seat of the pants feel. I can tell you specifically if your are having an ignition problem or fuel problem and I do not need a test light to know.
/quote]
Yes, of course I can tell the difference, as could any mechanic. That is my very point and why I have always been satisfied that it is fuel. However, other people probably have greater confidence in a test light that my arse! My arse had been called many things but never a scientific instrument. I don't believe "seat of the pants" was ever the correct answer in an exam either, hence the test light.
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
I am sorry that you fell I have questioned your authority, skill level or personal knowledge on this matter, it is not intended to question your ability, but you have posted incomplete finding on the topic and it looks like it struck a nerve; maybe not but it does to me.
I struggle with that one a bit. We are talking a very, very simple procedure here, one that I believe would not have any added credibility even if supported by a video. Determining when there is and when there isn't power to a wire.
Not sure how else I could take that but I will accept in good faith that it was not intended as it read and put it down as another example of things that don't necessarily travel well over the net.
Quote from: racerrad8 on September 27, 2013, 02:35:41 PM
Sometimes you have to take your own advice;Quote from: ribbert on August 17, 2013, 07:52:34 PM
I don't know why you even bought into this.
That's funny. I don't recall saying that and have no idea what it was in reference to but I was having very similar thoughts last night.
BACK TO THE MAIN SUBJECT
I am absolutely dumbfounded at how long this discussion has gone on for.
This has got to be THE easiest thing to settle I've ever come across.
Why don't (and I don't understand why this hasn't happened already) 1 or 5 or 10 or 20 of you just go and test it and post your findings. No shortage of people here that have demonstrated the skills and understanding to do this. Sufficient numbers of results should negate the need for supporting video evidence too.
Here's an easy one for pump equipped bikes. Take it for a ride without the side cover on and when it starts to splutter put you hand on the pump (after you've pulled over) and feel if it is still working, then flip the switch and feel again.
Or,There is a very good chance your tail light dims with the pulsing of the fuel pump at idle, have a look. Run you bike to reserve and before switching over, pull over and look at the tail light and see if it's stopped, then flick the switch and see if the dimming/pulsing resumes.
Or put a test light on the coils and rest it on the handle bars somewhere while doing the same.
I look forward to a resolution.
Noel
Pat, maybe at some point when in the winter months when I have down time with the bikes I could investigate. I am riding my bike daily, my wife and I are riding at least on day of the weekend, and I have more than enough work here at the shop to get back on the road.
I am not sure why anymore investigation or testing is required at this point. There seems to be enough consensus from members who have clearly stated based on the postings within this thread, who have read enough "proof" to close this topic.
Unfortunately, I am not convinced and I do not have the time, want, desire or the technical skill set to allow me to dissect the CDI to see if the fuel system has some form of control of the CDI.
My two 86's bike reserve functions work properly and I am not excited about applying power to my expensive petcocks or disassembling them to investigate either.
I will make my last post on this topic, with the technical information listed in the GYSM, with pictures to support my statements & interpretation.
Here is the ignition circuit with inputs & outputs.
There are two input circuits to the CDI regarding the fuel level and reserve systems and only one output to the fuel pump.
"I" - Fuel censor circuit
"J" - Fuel reserve signal input
"H" - Digital ignitor unit
"P" - Fuel pump driver circuit
(http://i1215.photobucket.com/albums/cc517/racerrad8/fuelpump001_zpsb2265a3f.jpg) (http://s1215.photobucket.com/user/racerrad8/media/fuelpump001_zpsb2265a3f.jpg.html)
Here is the "Fuel pump circuit operation" and fuel pump operation chart.
Now, like I stated earlier I do not have the skill set to understand the schematics, circuitry or this type of electronic knowledge to understand completely how the system is designed to work within the CDI unit. The GYSM does not address the reserve system and based on the chart at the bottom of the page below, the fuel pump runs or does not run at specific input requirements and the fuel pump is not listed as shutting off due to the fuel reserve circuit becoming active.
(http://i1215.photobucket.com/albums/cc517/racerrad8/FuelPumpCircuit001_zps98e8bd01.jpg) (http://s1215.photobucket.com/user/racerrad8/media/FuelPumpCircuit001_zps98e8bd01.jpg.html)
So, take it for what it is...
Maybe it works the fuel pump, petcock, CDI, and now something about the tail light bulbs...
Or maybe it doesn't.
I have provided the proof that Yamaha ran the fuel pump through the CDI at not one point but two. For sure, one circuit is the ignition signal for the fuel pump to run "For about 5 seconds when the fuel level is low" when the engine is off. That is the safety feature added in the event of a crash allowing the pump to shut down and not continue to pump fuel which could result in fire.
What is the second circuit that is an input to the CDI: a redundant low fuel warning system or maybe some sort of ignition circuit interrupt?
I have never said they are cutting two cylinders, I have read that several times and I do not believe that to be the case. I think they adjust the "Ignition coil driving circuits" ("Q" & "R" in the top picture) and induce a weak spark to signal the rider. Then when the switch is activated, the coil driver adjusts back to full coil power. The bike does not fall on its nose like the rev limiter that does the same thing, it stumbles & rumbles.
Just have a look at #3 of the ignition system operation...
Take the factual findings and printed interpretation of the information available from the GYSM or the observations that have been posted.
Maybe I'm wrong...but then again maybe I am correct.
Hell, if there is a solenoid in the early petcocks that stops fuel flow, that would have been great information to have known prior and that might have also stopped the fuel flow on Dan Filetti's petcock and maybe saved his bike from burning to the ground.
Sorry, Rich the myth still needs to be proved or disproved...anybody seen bigfoot? :flag_of_truce:
Randy - RPM
P.S. - Harvy, there is no such things as a "turbo fill" circuit of the fuel pump
Thanks for the ignitor layout Randy. Been a good discussion around the digital camp fire. I am sure everyone learned something or at least has something to think about.
A thought, if the ignitor is reducing the spark strength then I am thinking the only way that can happen is to lower the coil primary voltage when you go into reserve mode. I guess a volt meter hooked into that circuit and monitored when it go's into reserve might be a clue. But then again if the RPM drops the alternator voltage would go down..... Oh , well..... And then there are the riders who have installed a relay to get a full 12volts .....:dash2:
Laying on my back regaining conciseness after parting company with the FJ I think I did see big foot... He had a bottle of wine and mumbled something about "dumb shit".. :lol: :lol: :lol: By the time I got my helmet off he was gone...
George
Quote from: movenon on September 28, 2013, 03:34:04 PM
A thought, if the ignitor is reducing the spark strength then I am thinking the only way that can happen is to lower the coil primary voltage when you go into reserve mode. I guess a volt meter hooked into that circuit and monitored when it go's into reserve might be a clue. But then again if the RPM drops the alternator voltage would go down..... Oh , well..... And then there are the riders who have installed a relay to get a full 12volts .....:dash2:
George
George...stop thinking... :dash1:
I said I would not post anymore about the aforementioned material, but now George's thought requires explanation on how an ignition coil functions.
The CDI, just like the old cars with points, is an inductive ignition. Current from the battery flows through the thicker primary windings when the switching device (points or CDI magnetic pickups) is closed. This creates a magnetic field that builds strength thanks to the help of the iron core. When the switching device opens (the trigger signal) the flow of current is broken and this magnetic field collapses over to the thousands of secondary windings. During this collapse, the voltage is stepped up, creating the higher voltage that is required to jump the spark plug gap and ignite the air/fuel mixture. This process is called inductance.
The CDI does the same thing electronically as the old breaker point systems did. But, it can adjust the dwell time and control the output voltage of the coil(s) by shortening the electrical flow time (dwell). So, back in the old days of setting the point gap & dwell controlled the amount of electrical flow (dwell) to control the coil output. The CDI can make changes, based on inputs of intake vacuum signal, electrical flow of the reserve function or CDI programming.
The positive 12v side of the coils are not affected by the CDI and the addition of the relay ensures the coils are receiving the full compliment of power to obtain the maximum charge before the CDI breaks the electrical flow and the coil(s) discharge to the plugs.
Randy - RPM
Like George, I too have enjoyed this discussion. Thanks guys. :good:
:rofl2: :rofl2: (popcorn)
Have a good week end Randy :lol:
George
Quote from: racerrad8 on September 28, 2013, 02:57:33 PM
P.S. - Harvy, there is no such things as a "turbo fill" circuit of the fuel pump
That statement of mine was tongue in cheek Randy :biggrin: ...... all good, been an interesting topic.
Cheers
Harvy
Quote from: Pat Conlon on September 28, 2013, 04:32:30 PM
Like George, I too have enjoyed this discussion. Thanks guys. :good:
I enjoyed it as well...Learned a few things along the way. It looks like this discussion solved a problem Nimbus was having over in the "Strange fuel pump issue" thread. Sweet! :good2:
Cap'n Ron. . .
Quote from: racerrad8 on September 28, 2013, 02:57:33 PM
There are two input circuits to the CDI regarding the fuel level and reserve systems and only one output to the fuel pump.
"I" - Fuel censor circuit
"J" - Fuel reserve signal input
"H" - Digital ignitor unit
"P" - Fuel pump driver circuit
I have provided the proof that Yamaha ran the fuel pump through the CDI at not one point but two. For sure, one circuit is the ignition signal for the fuel pump to run "For about 5 seconds when the fuel level is low" when the engine is off. That is the safety feature added in the event of a crash allowing the pump to shut down and not continue to pump fuel which could result in fire.
What is the second circuit that is an input to the CDI: a redundant low fuel warning system or maybe some sort of ignition circuit interrupt?
I didn't think CDI control of the fuel pump was in question. It's a given for the argument that the fuel pump is turned off for the reserve function. There only need to be one output to the pump: the wire that activates the pump relay.
The 2 fuel signals make sense: Depending on the position of the reserve switch, the Low Fuel signal may or may not have any affect on the "logic."
With reserve switch in the ON position, the pump gets turned off when the Low Fuel signal activates.
When the CDI sees the reserve switch in the RES position, it turns the pump back on.
OR:
IF the rider ALWAYS leaves the reserve switch on the RES position, the CDI will ignore the Low Fuel signal and the rider will be able empty the tank with no warning whatsoever. I always choose this option and monitor my mileage using the trip meter.
So that's it? Randy declares the topic closed with an open verdict and everyone just drops it?
I would have thought at least one person out there would like their name in lights for being the one that provided "proof" by conducting a simple field test. It would be known for generations to come as "The ........... Solution"
Oh well, I guess some other subject is not far off that will engage us all in lively debate.
I have also learnt a lot from this discussion.......
Noel
Noel,
I tried to test it on my '92...I've got plenty of time to fiddle with such things and enjoy the process. Really helps me to not only figure it out, but to also remember it years from now when I'm on the side of the road with a fuel delivery issue. It's more about the "Why?" not just the "What?" for me.
Trouble is...Mine isn't functioning. Like one of the original posters, mine will just run me out of fuel in the ON position and I have to sort that issue out first. That being the case, there's not much more I can add.
Cap'n Ron. . .
Quote from: Capn Ron on September 28, 2013, 08:08:18 PM
Noel,
I tried to test it on my '92...I've got plenty of time to fiddle with such things and enjoy the process. Really helps me to not only figure it out, but to also remember it years from now when I'm on the side of the road with a fuel delivery issue. It's more about the "Why?" not just the "What?" for me.
Trouble is...Mine isn't functioning. Like one of the original posters, mine will just run me out of fuel in the ON position and I have to sort that issue out first. That being the case, there's not much more I can add.
Cap'n Ron. . .
No worries Cap'n Ron, I appreciate the sentiment.
Noel
Quote from: FJ_Hooligan on September 28, 2013, 05:55:05 PM
Quote from: racerrad8 on September 28, 2013, 02:57:33 PM
There are two input circuits to the CDI regarding the fuel level and reserve systems and only one output to the fuel pump.
"I" - Fuel censor circuit
"J" - Fuel reserve signal input
"H" - Digital ignitor unit
"P" - Fuel pump driver circuit
I have provided the proof that Yamaha ran the fuel pump through the CDI at not one point but two. For sure, one circuit is the ignition signal for the fuel pump to run "For about 5 seconds when the fuel level is low" when the engine is off. That is the safety feature added in the event of a crash allowing the pump to shut down and not continue to pump fuel which could result in fire.
What is the second circuit that is an input to the CDI: a redundant low fuel warning system or maybe some sort of ignition circuit interrupt?
I didn't think CDI control of the fuel pump was in question. It's a given for the argument that the fuel pump is turned off for the reserve function. There only need to be one output to the pump: the wire that activates the pump relay.
The 2 fuel signals make sense: Depending on the position of the reserve switch, the Low Fuel signal may or may not have any affect on the "logic."
With reserve switch in the ON position, the pump gets turned off when the Low Fuel signal activates.
When the CDI sees the reserve switch in the RES position, it turns the pump back on.
OR:
IF the rider ALWAYS leaves the reserve switch on the RES position, the CDI will ignore the Low Fuel signal and the rider will be able empty the tank with no warning whatsoever. I always choose this option and monitor my mileage using the trip meter.
As I wrote previously, the circuit includes the ignitor because it needs to "know" if the engine is running, so the fuel pump stays energized..... No other reason, there is no circuitry to affect operation of the ignition itself.
Rich,
I agree with your description. I was trying to explain the logic for the 2 fuel pump wires/signals and the reason the low fuel wire is not redundant.
te author=ribbert link=topic=9996.msg99508#msg99508 date=1380151496]
Quote from: Capn Ron on September 25, 2013, 05:40:40 PM
My understanding is that the sputtering you get from the engine when you hit the reserve level is the ignition being cut out on two of the cylinders??
I know this is a old subject but I will add this to it...i was riding when my sender unit or whatever it was that caused me to fill like I was running out of gas....looked at my fuel gauge an had half a tank so I switched it to reserve and all was fine....we had stopped a little further down the road to investigate....i had put my reserve switch back to the on position and went to get something to eat...when I got back to the bike and turned it on my fuel pump never clicked a few times to fill the bowls up but as soon as I switched it to RES there went the pump pumping away....since then my fuel pump never turns on with the res switch in the on position so something is cutting the fuel pump off, just not sure what it is...ive looked for bad connections all over the place and even bought a brand new relay but no luck
It has been said categorically here (by someone else thank goodness) that this is a myth. I agree.
If the coils were cutting out there would be an
immediate return to normal operation once the switch is flicked. There is not.
I believe it cuts the fuel pump out.
The behaviour of the motor, both when it indicates the need to go to reserve and when the switch is operated is entirely consistant with this. That is, it takes a few seconds to kick back in after it has been flicked. That lag is the time it takes for the bowls to refill.
A motor deprived of fuel or spark has entirely different characteristics and the function of the reserve switch is consistant with fuel starvation, not spark interruption.'
For those that need it proved, it would be a simple test.
Noel
[/quote]
This is one of those topics that I sat and read, and when it was over, I went to the shop and carefully dismantled the reserve switch, cleaned the 30 years of junk off of it, gave it a tiny smear of dielectric grease, tested it with a multi-meter, put it back together, and thanked everyone in my thoughts.
The COVID19 thing is likely leading to some superbly maintained implements.
Thanks again.
Best regards,
Ted