Here goes,
Bike fj1100 very hard to start when cold, never used to be only a recent thing.
Carbs are super duper clean just went threw them on weekend to be sure. Compression is 160 across the 4 and have 40 pilots. Battery is fully charged but coils are out of spec, one being 3.7 and one being 3.8 on primary.
Warm and hot starts are fine, kicks over first go but when cold i find that when choke is on and starter pressed it will crank but doesn't fire, fuel seems to be there cause i can smell it and see black smoke from exhaust so its fueling up just not firing which makes me think coils but not sure.
Let us know what you think? Its seems to fire much quicker if i have jumper leads hooked up to the car.
Thanks
Check your valve lash clearances.
Quote from: Fj.itis on August 18, 2014, 02:27:35 AM
Here goes,
Bike fj1100 very hard to start when cold, never used to be only a recent thing.
Carbs are super duper clean just went threw them on weekend to be sure. Compression is 160 across the 4 and have 40 pilots. Battery is fully charged but coils are out of spec, one being 3.7 and one being 3.8 on primary.
Warm and hot starts are fine, kicks over first go but when cold i find that when choke is on and starter pressed it will crank but doesn't fire, fuel seems to be there cause i can smell it and see black smoke from exhaust so its fueling up just not firing which makes me think coils but not sure.
Let us know what you think? Its seems to fire much quicker if i have jumper leads hooked up to the car.
Thanks
If you've got black smoke and petrol smell, something is burning, just not enough to start it and it sounds like classic flooding symptoms. Were the jet changes recent?
A low resting voltage in the battery and a further drop across the loom can leave you with a good cranking speed but not enough at the ignition.
If you have good compressions, the valves clearances will not be an issue, given the readings are taken at cranking speed.
Don't necessarily be fooled by the jumper leads starting it, you are also resting it while you hook them up which could also have some bearing on it.
We have some whizzo electrical guys here that will no doubt have a view that may solve your problem.
Try starting it on half choke and see what happens.
Good luck
Noel
Fuel fouled plugs....when were they last replaced?
Jeff
Did you clean the tiny orifices in the float bowls? The choke circuit get it's fuel from these ports.
If they are clogged/blocked then using the choke will only make cold starting problems worse.
Valve clearance done less than 2500 ago, jets have always been there, float bowl jets clear and i have been using half choke sometimes less. The waiting thing doesn't change things as I've given it time to rest but still wont start on its own when cold.
Plugs are unknown so that is my next point of call, seems unlikely because they operate fine when warm but who knows.
Just to be clear. It's not a jet. It's a pressed in fixed orifice in the port at the bottom of the float bowl.
It is tiny and easly obstructed by debris.
Also, do you still have the 4 hoses that connect to the carbs just above the float bowl?
Yeah all those pressed passages in the float bowl are clear, i checked 2 days ago now.
No all the hoses are gone but i have no leaks or overflow to speak of. Everything has been going great until now for about 2500 km.
Cheers
Update:
12.4 volts going into coil, just put in new plugs and still no start. Pulled out plug and attached it to lead and grounded it on head bolt now i have no visible spark, yesterday i could see some random spark but nothing after new plug change.
Im starting to think coils are shot, what are your thoughts?
Quote from: Fj.itis on August 18, 2014, 06:56:34 PM
Update:
12.4 volts going into coil, just put in new plugs and still no start.
Is this the voltage while starter is cranking or at rest? If at rest, check whilst cranking. Might be time for the coil relay mod? Pete.
Quote from: Fj.itis on August 18, 2014, 06:56:34 PM
Update:
12.4 volts going into coil, just put in new plugs and still no start. Pulled out plug and attached it to lead and grounded it on head bolt now i have no visible spark, yesterday i could see some random spark but nothing after new plug change.
Im starting to think coils are shot, what are your thoughts?
It could be the plug cap on the no spark issue. It is a resistor cap. Try one of your other caps. The wires are solid core.
The resistance between the 2 plug wires from the coil should read around 12K +- 20%. That is just the wires without the caps on.
George
So the coils work okay when hot but not when cold. For an electrical problem, I would expect the opposite.
Still smells like a choke circuit issue to me
Ok, checked the voltage while at rest, will check again under cranking conditions.
I havent started it today to find out if i can start it but it looks like ive got no spark at all now.
Will do some more testing and ill let you know.
As far as the choke circuit goes, ive cleaned the carbs to within an inch of their life and have clearance through all passages, other then that i dont know what else to do with choke circuit.
Pickup coils 160 ohms manual says 132 max
Plug caps resistance 5k ohms manual says 1k max
Coils primary 3.8 and secondary 13k ohms . Manual says 3.2 max for primary, secondarys in spec.
Now when i test for spark im getting some spark from right coil but none from left. So i switched the inputs and put the right input on the left coil and got some spark also. Doesnt seem like much though.
Now cranking voltage at coil inputs is 10 volts on both inputs when going from positive to a ground, but if i go between the two input pins on the right coil i get a voltage whilst cranking but no voltage between two pins on left coil, not sure if that is normal?
Anyone got ideas where to go from here based on this info?
Got it started from dead cold on its own but with great amount of fiddling around with choke on until it sounded flooded then choke off and it eventually cranked over with choke off.
So heres my theory, there is spark there obviously, but not visable to me on one coil only. This could be weak spark i dont know but i think across the board the spark is just lame due to out of spec ignition and pickup coils and also huge plug cap resistance . So enough spark when warm due to fuel vapourizing better but not enough when cold, hence having to adjust the amount of fuel in the the pots with choke on and off when cold.
Could be wrong but its the only thing i can think of, because it runs and starts fine when hot.
From your figures I would replace the caps to start with. How is your spark without the caps on ? How ever that's not going to solve the low voltage problem. You can't get voltage or current at the end if it's not there to start with.
I would go back to the beginning of the circuit how is your battery voltage? Be aware that you can have voltage and not enough current. A quick and dirty test is just use some jumper cables and jump from your car battery (assuming it is good). I had a brand new battery once for the FJ that had good voltage but would fall flat on its ass under any load. You did the jumper configuration and mentioned that it fired much quicker when you jumped it... IMO the weakest link and highest wear item is where it starts at, the battery. Resting voltage should be close to 12.7 volts for a good acid cell battery.
If you can get it running what is your charging voltage ? It should jump up to 13 plus volts. Max is 15 volts.
You can have voltage loss at any of the connectors. Even from the back side of the fuse box, interlocks, run stop switch etc.
In the end, yes you can have bad coil or coils but somehow I don't think they are that bad. I might be wrong someone else can give there opinion on that.
Jumper the battery, check to see how much spark you have without the plug cap on ?
Pick coils I think are just a switch control or signal for the CDI. Will not effect low or high voltage. It is just a magnetic pulse. If a coil is absolutely dead then there might be a signal or switch loss. Pick up coil winding spec is 120 ohms +- 10%
George
How are you ohming the coils? Are they completely disconnected?
Quote from: Fj.itis on August 19, 2014, 06:44:28 PM
Pickup coils 160 ohms manual says 132 max
Plug caps resistance 5k ohms manual says 1k max
Coils primary 3.8 and secondary 13k ohms . Manual says 3.2 max for primary, secondarys in spec.
Now when i test for spark im getting some spark from right coil but none from left. So i switched the inputs and put the right input on the left coil and got some spark also. Doesnt seem like much though.
Now cranking voltage at coil inputs is 10 volts on both inputs when going from positive to a ground, but if i go between the two input pins on the right coil i get a voltage whilst cranking but no voltage between two pins on left coil, not sure if that is normal?
Anyone got ideas where to go from here based on this info?
How are those readings different when the engine is hot? I posted earlier about checking valve clearances as valves that are too tight will make cold starting very very hard as the engine cannot build compression. Most folks are more interested in possible electrical issues rather than simple mechanical ones. (electrical problems have a more mystical quality I guess). :biggrin: While it may be electrical I have personally cured well over 100 "cold start" problems (when I owned my bike shop) with a simple valve adjustment.
are you SURE all the "choke" mechanisms are working and are synchronized? If they are not, you'll get pretty much exactly what you describe on the starting behavior... spark issues aside.
Frank
Would i have valve issues if I've got 160 psi across all 4? Valves done 2500 thou ago.
With out plug caps on spark was exactly the same.
Measuring coils with them disconnected.
Battery is lithium and putting out over 13 volt normal and voltage regulator is new and working fine. Battery kicks the motor over very quick as its 240 cca
I just let it cool again and come back out kicked it over with choke on but it didnt start then took choke off again and it started right away. Its like there is to much fuel for the spark when its on choke but then turn it off after fuel has dissipated a bit and it fires.
Is it normal for the choke to kill the engine when you turn it on when engine is warm? It sounds like the choke is flooding engine.
Quote from: Flynt on August 19, 2014, 10:28:16 PM
are you SURE all the "choke" mechanisms are working and are synchronized? If they are not, you'll get pretty much exactly what you describe on the starting behavior... spark issues aside.
Frank
Yeah i had the carbs off two days ago and could see the plungers moving in and out as i played with choke. Not sure on the synchronised thing but they are all moving together. Is it possible to be letting to much fuel in as if i leave choke on while cranking it will backfire like there is to much unburnt fuel in there.
Quote from: Fj.itis on August 19, 2014, 10:29:44 PM
Would i have valve issues if I've got 160 psi across all 4? Valves done 2500 thou ago.
With out plug caps on spark was exactly the same.
Measuring coils with them disconnected.
Battery is lithium and putting out over 13 volt normal and voltage regulator is new and working fine. Battery kicks the motor over very quick as its 240 cca
I just let it cool again and come back out kicked it over with choke on but it didnt start then took choke off again and it started right away. Its like there is to much fuel for the spark when its on choke but then turn it off after fuel has dissipated a bit and it fires.
Is it normal for the choke to kill the engine when you turn it on when engine is warm? It sounds like the choke is flooding engine.
160 psi, damn, you wanta trade.... :lol:.
Have you done a plug reading? And you are sure that all the choke plungers are seated in all the way..
Why do you want the choke on when the engine is warm ? I guess you can flood it that way, certainly run like crap. I only need my choke on when stone cold. After it has been running I can start it an hour later without the choke.
George
Quote from: movenon on August 20, 2014, 12:32:14 AM
Quote from: Fj.itis on August 19, 2014, 10:29:44 PM
Would i have valve issues if I've got 160 psi across all 4? Valves done 2500 thou ago.
With out plug caps on spark was exactly the same.
Measuring coils with them disconnected.
Battery is lithium and putting out over 13 volt normal and voltage regulator is new and working fine. Battery kicks the motor over very quick as its 240 cca
I just let it cool again and come back out kicked it over with choke on but it didnt start then took choke off again and it started right away. Its like there is to much fuel for the spark when its on choke but then turn it off after fuel has dissipated a bit and it fires.
Is it normal for the choke to kill the engine when you turn it on when engine is warm? It sounds like the choke is flooding engine.
160 psi, damn, you wanta trade.... :lol:.
Have you done a plug reading? And you are sure that all the choke plungers are seated in all the way..
Why do you want the choke on when the engine is warm ? I guess you can flood it that way, certainly run like crap. I only need my choke on when stone cold. After it has been running I can start it an hour later without the choke.
George
Yeah plugs read fine after a good ride, there is nothing wrong with the bike other than this cold start issue that has just surfaced. Choke plungers cant be pushed in anymore when choke is off, so im assuming they are seated. The problem seems to be when cold and choke is on, bike doesnt want to go.
I dont want the choke on when warm just trying to ascertain if that it is normal function which im sure it is, as it pumps the fuel in there, so definitely not blocked and have no idle issues at all.
I know that I keep saying it but try cleaning up the main earth on the back of the engine or do like I did and fix an extra earth to the starter mount. My 3cv turned into a hissy mare overnight. One day starting and running well and then nothing or spitting and banging while firing on odd cylinders. It took me several days to find the problem and five minutes to fix it.
Quote from: Fj.itis on August 20, 2014, 02:23:41 AM
Quote from: movenon on August 20, 2014, 12:32:14 AM
Quote from: Fj.itis on August 19, 2014, 10:29:44 PM
Would i have valve issues if I've got 160 psi across all 4? Valves done 2500 thou ago.
With out plug caps on spark was exactly the same.
Measuring coils with them disconnected.
Battery is lithium and putting out over 13 volt normal and voltage regulator is new and working fine. Battery kicks the motor over very quick as its 240 cca
I just let it cool again and come back out kicked it over with choke on but it didnt start then took choke off again and it started right away. Its like there is to much fuel for the spark when its on choke but then turn it off after fuel has dissipated a bit and it fires.
Is it normal for the choke to kill the engine when you turn it on when engine is warm? It sounds like the choke is flooding engine.
160 psi, damn, you wanta trade.... :lol:.
Have you done a plug reading? And you are sure that all the choke plungers are seated in all the way..
Why do you want the choke on when the engine is warm ? I guess you can flood it that way, certainly run like crap. I only need my choke on when stone cold. After it has been running I can start it an hour later without the choke.
George
Yeah plugs read fine after a good ride, there is nothing wrong with the bike other than this cold start issue that has just surfaced. Choke plungers cant be pushed in anymore when choke is off, so im assuming they are seated. The problem seems to be when cold and choke is on, bike doesnt want to go.
I dont want the choke on when warm just trying to ascertain if that it is normal function which im sure it is, as it pumps the fuel in there, so definitely not blocked and have no idle issues at all.
Hard to trouble shot via the internet sometimes :good2: Here is a picture of how those 4 plungers should look when all the way in.
(http://fjowners.com/gallery/7/1651_20_08_14_9_21_12.jpeg)
George
The 4 hoses that aren't there anymore. Are they still open to atmosphere?
Yeah still open.
Plungers are well seated going off that pic.
I would of thought if it was a fuel issue, id have problems even when warm. The spark this thing produces is really faint, anyone care to pull a plug and see what their spark looks like? Maybe a photo if possible?
Years ago, I recall someone smarter than me posting that the CDI ignition will not produce a big fat spark.
Is that an "all or nothing" symptom? IOW, does it try to run off of 2 cylinders like it's dropping one of the coils?
Or, does it just not want to run on any cylinders when the choke is on?
Nah not dropping any cylinders, just no signs of life when cold cranking and choke is on. Have to turn choke on and off to get it to fire. The last time i tried just jumping it from car with choke on and it still wouldn't fire, as soon as i turned choke off no throttle it fired right up.
Im going to borrow a set of coils just to humour myself and at least eliminate one potential problem, will post back and let you know what happens.
Thanks guys for all your input really appreciate and take on board all suggestions.
Quote from: Fj.itis on August 20, 2014, 04:30:15 PM
Nah not dropping any cylinders, just no signs of life when cold cranking and choke is on. Have to turn choke on and off to get it to fire. The last time i tried just jumping it from car with choke on and it still wouldn't fire, as soon as i turned choke off no throttle it fired right up.
Im going to borrow a set of coils just to humour myself and at least eliminate one potential problem, will post back and let you know what happens.
Thanks guys for all your input really appreciate and take on board all suggestions.
Without looking at the wiring diagram the 12 volt line (R/W) might have to travel trough the clutch switch and possably the run/stop switch ? If they do you might clean them up or for a test just bypass ?
George
Yep, both been done gave that a shot yesterday. Thanks
Here is a clip of a yamaha with similar engine to ours showing how much spark it produces. Mine had nowhere near that much and i couldnt get it to jump to the head bolt from a screw driver either. Check it out. Fast foward it to 1.54
https://m.youtube.com/watch?v=jaSKU2m3qbI
Power your coils directly off the battery...see what that spark looks like.
If the bike starts fine when warm, but not when cold, I'm thinking along the lines of Hooligan.
Something's flooding.
Your right is it flooding but the choke enricher circuit is only so big it cant let any more fuel then the maximum amount and its verified that its closing when shut off and i have no other leaks to speak of so that leaves the cause of the flooding not enough spark but we shall see.
Did you see that vid of that spark? I am not getting anywhere near that so somethings up with the spark regardless.
Ok guy's problem solved...
It was the coils as i suspected causing the engine to flood when cold. So check your spark! If it doesnt like like the video i posted then your running a weak spark and fuel economy and power will suffer. Due to me not owning an fj before i didnt realize, 1 the fuel economy and 2 the difference in power, now ive got better of both. We will chalk that one up to inexperience.
Hope this has helped someone out there with spark problems or hard to start problems.
Cheers
Well there is more to the saga!
3 days after i changed the coils it started to go the same way again and eventually wouldn't start at all, no tricks would get it to start. So after some more testing and mucking around traced it back to the ignitor one channel was non existent and the other ok. Changed it over and she is sweet again, not sure why i got normal spark again after the coil change but stranger things have happened.
So end result still was spark but not the coils, learnt heaps about the ignition and how to properly test from this experience hope my drama helps others.
Cheers