I'm chasing a high rpm studder on my '84.
The bike starts and runs fine (really good actually) until above 7.5k rpm where a intermittent studder kicks in.
I've replaced the 32 year old oem ignition coils with new Dyna green 3 ohm coils. I have the coil relay mod done..good juice to the coils.
I checked continuity and ohms of the coil trigger wires from the TCI plug to the coils...wiggled the connector wires looking for bad connections.
My question is: In both the Clymer/Haynes Workshop manuals they specify a ohm resistance reading on the TCI pick up coils (orange to black and gray to black at the TCI plug) of 120 ohms +/-10% at 68*F (108-132 ohms) I warmed up the pick up coils with a hair dryer.
I checked mine and they are 159 and 160.....I have a spare back up set of pick up coils and checking those they are at 160-161.
Are both sets of pick up coils bad or is the ohm value wrong?
I can see one (of the 2) pick up coils reading high...but both sets? (all four pick up coils? unlikely)
Don't play around with it. Call Randy and discuss. Might even be a sticky valve or...?
it's definitely a ignition studder...
Valves are good, plug readings look good.
email is sent to Randy.
I have a back up TCI ignition box I'm going to swap in.
Quote from: Pat Conlon on March 12, 2015, 11:27:33 AM
I'm chasing a high rpm studder on my '84.
The bike starts and runs fine (really good actually) until above 7.5k rpm where a intermittent studder kicks in.
My question is: In both the Clymer/Haynes Workshop manuals they specify a ohm resistance reading on the TCI pick up coils of 120 ohms +/-10% at 68*F (108-132 ohms) I warmed up the pick up coils with a hair dryer. I checked mine and they are 159 and 160.....I have a spare back up set of pick up coils and checking those they are at 160-161.
Are both sets of pick up coils bad or is the ohm value wrong? I can see one (of the 2) pick up coils reading high...but both sets? (all four pick up coils? unlikely)
Pat,
Do you get the stutter when parked, or only at speed? If it is good at high RPM standing still, then I would look for a dirty air filter, or
anything that changes the way the engine gets air (inlet boots, altered covers and panels, et c.).
You may be starving for gas at high RPM, also. When riding with half a tank of gas or less, run the engine up to the start of the stuttering. Back off the throttle, pop the gas cap for a second, close the gas cap, and see if you still have the stutter then. The gas cap vent may be plugged, or partly plugged. Do this next part outdoors, as you will create lots of gas fumes. Use a siphon hose to "vacuum out" the bottom of the gas tank into a clean plastic catch bucket. If you get a lot of rust and crud in the catch bucket, the tank needs cleaning. Apply a suction to the vacuum hose of the petcock, strong enough to let the petcock flow the fuel. Blow compressed air generously from the carb end of the fuel line, back up into the tank, to clean the screen in the tank. Then clean out the gas tank.
No matter what the pickup coils read in Ohms, coil values are best measured in Henries, not in Ohms. If an electronics geek there can show you that the Henry values of the pickup coils are all the same, then they are all good. An Ohms reading usually can not spot the slight failure in a coil that might cause your problem.
Cheers,
Red
With it being electrical there are so many things it could be. If swapping the TCI doesn't cure it I would unplug your tach and see if the problem is still there. Dave
Thanks Red, gas is good, tank is clean, cap is vented, carbs clean, carb jetting is good.
Again...it is a ignition studder...very slight, intermitent, comes and goes.
I only rev out my engine under load in 3rd gear (sometimes 4th and 5th) never in neutral standing still.
My primary question is why the "apparent" low ohm value for the coil pick ups?
....or is it really a low ohm value? (120 +/-10%) All 4 of my coil pick ups are within 2 ohms of each other.
Has anyone else noticed this?
Swapped in the back up TCI, and the problem still exists.
Thanks Dave...I'll disconnect the tach wires and see what happens.
Maybe try temporarily wiring around the coil relay. Where is the relay mounted?
At high RPM maybe vibration could be jacking with the relay connection? Maybe try a new relay?
Just a wild idea....
Let me know if you want to swap over to a Dyna.
(I "might" have an extra one lying around) :-)
Thanks Hooli...
The relay is up front above where my charcoal canisisters used to be.... I'll plug in a new relay. I put heat shrink on all the spade connectors on the base plug, I would hate to have cut that all open.
Hooli, you just gave me an idea....if the relay (that powers both coils) was acting up, the studder would be severe and dramatic...which is not the case...
Hmmmm.
Perhaps 1 plug is acting up? Sure feels like it....I'm gonna put a new set of plugs in and see what happens.
Sometimes (most of the time) it can be the simplest of things....wouldn't that be something?
your books are wrong. my GYSM says pickup resitance is 149~182 ohms at 68*F
so the pickup is not the trouble
Hey Pat, wow third gear is where the fj lives.
I recall the coils for the tci are different from the dci ign , if you use the hot coils on the tci you will cook it. ( one of those things i learned and forgot why. )
I like the check the plugs idea, and you may have a sprk boot or wire having a crack . spray with water and see if it causes a miss while running and lights you up.
A tear in one of the diaphragms of the carbs will act similar but don't you have flatsides on that bike?
Lots of ideas tossed around Post up what you find.
Thanks Coop! :good:
Randy at RPM just e-mailed me and said the same thing. Correct values = 149-182 ohms at 68*F
Randy tested several pick ups, both early TCI dual pick up, and late model DCI single pick up, and they all came in at the 160-165 ohm range....
My suspicion is confirmed.
So, let it be known that both the Clymer and Haynes Workshop manuals are WRONG WRONG.
Thanks Mark, the Dyna green 3 ohm coils are compatable with the early FJ 2.8 ohm TCI ignition.
You do not want to run coils with a lower ohm value than your ignition (like the Dyna gray 2.2 ohm coils)
Fresh plug wires/boots (Dyna gray resistor core) remember the problem existed before the new coils.
Quote from: Pat Conlon on March 12, 2015, 04:45:22 PM
....if the relay (that powers both coils) was acting up, the studder would be severe and dramatic...which is not the case...
Good point. If the power was intermittent then it would be very severe missing and probably cause a lot of backfiring from mis-timed plug firings.
Spark plugs may be a good idea. You said you were using Dyna wires? On mine, I have to watch out for the screw-on tip of the spark plug loosening up. Seems like everytime I pull a wire, one or more of the screw-on tips is loose.
Hey pat I just remembered something that happened to me similar to your problem.
The run/kill switch was acting up on my 86 and would cause a miss at the rpm you are talking about.
problem only in the fun rpm zone in third gear.
Check that out.
I took it apart and cleaned it and used the dielectric grease on the contacts.
Good luck.
Now that you mention it Mark, I have a strange Kookaloo issue. Many times when entering the Kookaloo zone I will discover my turn indicator starts blinking. Many times I have been riding for some time on the road so I know the signal would have timed out many miles ago. But after the fun acceleration I find it blinking away.... Since the impact to my riding enjoyment is very low I have not bothered to root cause it. I know I have already cleaned the switch contacts a few years ago. So it may be from vibration or the G's pulled during a good run.
Back to your regular channel...
Quote from: FJmonkey on March 12, 2015, 05:47:02 PM
Now that you mention it Mark, I have a strange Kookaloo issue. Many times when entering the Kookaloo zone I will discover my turn indicator starts blinking. Many times I have been riding for some time on the road so I know the signal would have timed out many miles ago. But after the fun acceleration I find it blinking away.... Since the impact to my riding enjoyment is very low I have not bothered to root cause it. I know I have already cleaned the switch contacts a few years ago. So it may be from vibration or the G's pulled during a good run.
Back to your regular channel...
Yeah , just cause you did it once upon a time dosen't mean you won't have to do it again.
Part of my spring maintenance schedule.
Thanks Guys...!
Hooli, yep, when I put the Dyna cables on I had to convert over to the screw on plug tips,,,I made sure those puppies where tight.
Thanks Mark, I'll disassemble the kill switch and clean it...it's been several years since I've done this...good reminder. :good:
....to be continued
Quote from: Pat Conlon on March 12, 2015, 04:45:22 PM
Sometimes (most of the time) it can be the simplest of things....wouldn't that be something?
Wizard needed a strong dose of Techron and new plugs at 10K... at least that was the first interval with the 1350. I talked to Randy suspecting something bigger as it was not acting normal... down on top end power with a "lean feeling" (studder?) at higher RPMs. I'm at about 17K now, so we'll see if it comes back soon enough.
Frank
Does the stutter occur at a constant RPM or only when accelerating hard? The things i suspect on a miss under a high RPM load are the coils, plug resisters or plugs.
Thanks Frank, that's good to know about the Wizard. Did the plugs look abnormal?
Chris, the ignition studder is momentary and clears quickly as the RPM's continue to rise, around 7.7~8k range. I also notice a fluctuation in the tach needle when this happens.
If it was a fuel delivery issue the tach needle would stay constant.
Definitely ignition, no doubt in my mind.
We shall see with new plugs.
Quote from: Pat Conlon on March 12, 2015, 10:19:06 PM
I also notice a fluctuation in the tach needle when this happens.
At last, a clue. If the tacho needle is bouncing in synch with the miss, it's getting an electrical interruption to the power supply and I would start by hunting around some of the primary wiring.
With motor running, push, pull, tug, drag etc all the wiring you can access and see if disturbing it causes the miss at idle.
Electrical problems: 2 days to find, 2 minutes to fix.
Noel
Quote from: Pat Conlon on March 12, 2015, 10:19:06 PM
Did the plugs look abnormal?
Pretty much... even color across the 4, slightly more carbon than you'd want (FCR accelerator pumps I suspect) but nothing that would make me change them. I did the tune-up as first step of diagnostics and the issue went away immediately. The Techron booster (I normally run Chevron fuel, but I added the concentrate as well) was added to ~1/2 tank and I rode ~5mi to top off the tank. I then rode about 150miles and Wiz was back to normal ferocity by the end of it.
I had the jumpy tach needle issue pre-rebuild and never really found the cause. During the build we made sure the coil ground was done right and the tach has been happy since... maybe coil grounding could be your issue?
Frank
Quote from: ribbert on March 13, 2015, 02:30:13 AM
Quote from: Pat Conlon on March 12, 2015, 10:19:06 PM
I also notice a fluctuation in the tach needle when this happens.
At last, a clue. If the tacho needle is bouncing in synch with the miss, it's getting an electrical interruption to the power supply and I would start by hunting around some of the primary wiring.
With motor running, push, pull, tug, drag etc all the wiring you can access and see if disturbing it causes the miss at idle.
Electrical problems: 2 days to find, 2 minutes to fix.
Noel
Pat - I'd consider temporarily taking the coil relay mod off and doing a test run. Or - replacing with another relay. The mechanical points could be reacting to the vibration at that particular RPM range -- especially if the relay has been in for a while.
Also - what carbs? CV's?
edit -- OOPS - see where Hooli went there already!
Thanks Noel, yep that is the drill, yes, partial connections are tricky to find..
You really need a ohm reading to show up...a continuity light or buzzer won't cut it.
Frank, that was first on my list to rule out, the ground. All connections are scrubbed and clean.
There is a dedicated ground (along with power) home run back to the battery when the coil relay mod was done.
Chris, yes, still on the CV 36's.
Randy is working on re-spacing a set of GSXR750 Slingshot 38CV's I will experiment with this summer after the WCR and Central Rally.
I'll plug in a fresh relay, just because I have it....(same 30a relay as my headlight mod, I always keep a couple of spares)
Pat - asked about the carbs - wondering if something is causing one or more slides to "flutter" at that point (creating a lean stumble) and then pulls through it? Also, how's the battery? I've had one start to go bad that would cause an ignition miss before it showed any other signs.
Chris
Carbs are good. Clean. Diaphragms good, slides move freely and drop equally.
Battery is 2 years old. Starts fine. Hot starts fine (XJR starter) Battery voltage good.
Pat,
It is 10am now , haven't you changed the plugs yet?
:biggrin:
Had to work (kind of) yesterday..
So this morning, fresh plugs, recleaned the 2 TCI plugs and the 2 connectors to the coils, new coil relay and cleaned the handlebar run/stop switch....the bike starts and purrs like a kitten, a 15 mile warm up then a Kookaloo blast down my favorite deserted desert road and....the studder is still there...barely.
Very slight studder at 7200 then pulls cleanly thru that all the way to 10k. Still the bike runs very strong.
So to recap, since the start of the symptom:
1) new Dyna 3 ohm coils wires boots and plugs.
2) ohm checked the pickup coils. Ok at 160 ohms (thanks again Coop, Randy) Values in Clymer/Haynes wrong.
3) swapped in a different TCI
4) new coil relay.
5) cleaned run/stop switch, 2 TCI and 2 coil connector plugs. Ohm checked and wiggled coil signal wires from TCI to coils.
Next on my list is to pull the tank again (sigh) and disconnect the tach leads at the coils. Perhaps something goofy is going on with the tach?
Either way it is a very very slight studder, not really a big deal but still...its ttthere...and gone in a flash.
I don't spend a lot of time riding at 7200 rpm.
The search continues...
A thought here, :scratch_one-s_head:
Install a known good set of OEM coils and make no other changes, take it for another romp through the canyons.
Fred
Pat, the bouncing tach could mean a voltage supply problem. I followed Aviation Fred's link and purchased a 84/85 wiring diagram that shows the harness connectors but that will take a week to arrive. Probably a harmonic from the engine vibration at 7.2K.
Chris
Fred, the oem coils I took off tested fine...I had the Dyna greens laying around the work shop for 5 years so I figured, what the heck...
Chris, no bouncing of the tach needle, nothing big like that.. just a little flutter at 7.2k then normal readings as the bike flat boogies to 10k.
I think you may be on to something re: harmonics. It happens exactly at (according to the tach) 7.2, not 7.1 or below...or 7.3 and above.
After I disconnect the tach to what happens...my next move is to remove the fairing and start pulling plugs apart.
If the coil relay was the culprit or the (ignition switch) power supply to the relay coil, the power interruption would be dramatic...both coils would be affected. This is not the case.
The next move after that, will be running 2 new coil signal wires from the TCI to the coils....and after that, replacing the coil pick ups with my back up set.
I want to do this one step at a time to see what brings the desired results.... As Noel said, 10 days to find the problem, 10 minutes to fix.
It's day 5 -- half way done yet?!! :lol:
I had company all weekend...no chance to work on the mistress... A busy time here in the desert with house guests.
Worked yesterday and this morning....nothing to report. I'm thinking it could be a signal problem between the TCI and coils via the oem harness.
My final test will be bypassing the oem harness and running signal new wires....after that, I'm out of ideas.
My buddy Paul Lawson and his son Jason will be coming Thursday to pick up Jason's '93 (exABS) bike I've been working on (a lot of work)
...as well as Paul's 'new' '92 (my '92 I sold to Paul) I'm gonna shelve further work on my '84 until things calm down here at home, perhaps next week.
My '84 currently runs very good, very strong, other than that brief little studder....
If or when I ever figure out the cause, I'll report back.
Quote from: Mark Olson on March 12, 2015, 05:32:43 PM
Hey pat I just remembered something that happened to me similar to your problem.
The run/kill switch was acting up on my 86 and would cause a miss at the rpm you are talking about.
problem only in the fun rpm zone in third gear.
Check that out.
I took it apart and cleaned it and used the dielectric grease on the contacts.
Good luck.
Ok I found it....Mark ^^^ gets a free breakfast at the WCR.
I've had a house full of company for the last 3 weeks and yesterday everyone left....a quiet morning with a cup of coffee is wonderful...looking at the wiring diagram for my '84 I see that the ignition box (TCI) is powered by its own circuit (red wire/white stripe) and that circuit runs from the fuse block through the run/stop switch on the handlebar and then down to the TCI.
Previously I did disassemble the run/stop switch and cleaned the contacts, checked the little pressure spring that holds the contacts together...but the problem remained.
What I did to rule out a electrical supply problem to the TCI was to run a temporary jumper wire from the fuse block directly to the TCI.....I went for a ride, warmed her up, then visited the kookaloo zone....the studder is gone. :yahoo:
So that means that there is a problem in the circuit that runs through the run/stop switch. Careful checking with my multimeter showed which side of the switch (fuse to switch and switch to TCI) the problem was on.
The problem was in the wire between the switch and the TCI, after the connector block.
I *guess* what was happening was that the studder was somehow vibration related....at a certain rpm 7.2k the vibration caused the broken strands in the wire to lose conduction...I ruled out a voltage/amperage issue because the bike would run well in the 7.3k to 10k rpm zones.
Thanks Mark :drinks: see you at the WCR! Also a shout out to FJ Monkey Mark for taking the time in doing a continuity check for me....it was very much appreciated! When Mark reported that the run/stop switch opened the circuit in the stop mode and thus de powered the TCI, I knew where to check, and what to do..
Even with a house full of hyped up grand kids, I've been thinking about this for weeks...my subconscious does not like unresolved problems. My reticular activating system helped clarify things even in the mist of chaos.
We now return you to your regular program.....
Allright :good2: yeah I like breakfast .
Good job on the follow thru to find the problem source pat. You must be a happy camper now.
Thanks again Mark...is it rally time yet?
Quote from: Pat Conlon on April 13, 2015, 01:33:37 PM
Thanks again Mark...is it rally time yet?
No not yet ...still got some things to do.
(http://fjowners.com/gallery/8/16_08_04_15_12_36_37_0.jpeg)
Quote from: aviationfred on March 14, 2015, 08:52:06 PM
A thought here, :scratch_one-s_head:
Install a known good set of OEM coils and make no other changes, take it for another romp through the canyons.
+1 usually these aftermarket sets dont work
seen that tested that by seeking my bikes running problems
Fred