Random misfire when hot

[MrSled]

That's what I was thinking. I too cut that tab. everybody should cut off this useless appendage.



I doubt that very much as that relay only supplies power to the starter, unless you also count the fuse for the fuel pump that comes with it.

My MP (same engine) has almost 17k km and purrs like a kitten. Unless it's been run on vegetable oil, the valves should be OK. I'd be looking for something that's supplied to the engine (spark or fuel). that's amiss. We'll see after you get a good ride in.

and. after all the sled I have seen. None of them are the same to the extend to rule out a valve adjustment. But whatever.

 

[Mooseman]

Yeah, anything is possible . Sometimes you can't discount anything.

 

[maim]

well we are not the only owner of this sled and i know it was abused by the po because of some of the damage i had to repair on it. po might have let it bounce off of the limiter all day for all we know.

 

[kirkswim]

Okay so took it for a ride not misfire at start but after letting it idle and the fan came on misfire. Drove for a but misfire gone never happened again. Okay the misfire is not constant when hot I can drive for 20 minutes misfires once, then nothing for awhile, if warm out misfires more often. Temp light does not come on. One notice after the starter and starter solenoid change is before when warm/hot had tro crank for 5-10 sec to start now with stock starter hits second cylinder and running.

 

[Mooseman]

Have you gone in the diagnostic mode and see what the fuel settings are like and if they have been changed from stock?

 

[kirkswim]

Yes gone into diagnostic mode cleared all past codes and reset everything to stock. Went for a 20 minute ride today and no misfire.

 

[Handy]

Could possibly have been a sticky valve. It will free up with regular use. Very common on 4 stroke engines that have been abused and neglected.

 

[kirkswim]

Well figured it out now waiting on parts. Last weekend after 50 miles code 34(cylinder 2 coil) Maim can and picked me up, it cooled off on the truck ride home and ran on both with no code when unloading. Tried a couple times during the week and could not replicate. So this weekend since it was right around freezing temp wise took it to camp(only 2kms across lake so if I had to walk no big deal) Made it 1/2 way and code 34 again. So limped it to camp and while still hot took it apart. Cylinder 2 coil wires were half broken(discovered when I disassembled the plug) there was only4 strands of copper still connected just as the wire left the plug. So my theory currently is as the wire/coil temp increased due to use, the resistance went up causing weak spark and possibly causing the cdi to see a resistance out of spec and throw the code 34. Used wiring harness will be on its way from Barn Of Parts.

 

[maim]

and the old vk got her towed back to the truck. slush was nuts on the lake. glad i took the vk.

 

[kirkswim]

Got the harness from Barna parts and Travis also sent me a coil plug to spice in and try that . Spliced it and tried it with just the plug repair giving a little more length to the wires so they wouldn't be so tight did 30 miles today not a misfire best it's ran in probably the last two years . We'll see if it keeps going good the whole winter then look at changing the wiring harness in the summer and now that I have a spare that has less than 1000 miles on it while the sled has 10,000 miles on it .