Missfire comes and goes!?!?

[crazycoot80]

This is quite a wierd problem!! I have a 95 talon AWD with a JDM 6 bolt swap. Just replaced the head, timing belt and installed 272 cams, headder, timed it all up perfectly. Has big 16g turbo and stock injectors and im only running stock boost because i have yet to upgrade to DSM Link. When I replaced the head I installed Brian Crower cams and valve springs and retainers, new NGK plugs gapped to .28 and new plug wires. The cylinder that is missfiring is #1 and it comes and goes. I will be just driving down the road and then bam!! Engine starts running roughand the miss wont go away till i shut the car off and let it sit for a while. Then i start it up and its fine for a while then it happens again. When it is missing and i remove the #1 plug wire it arks to the plug tube like crazy so the spark is getting to the plug and when i pull the plug it does not look fouled. The only thing i can think is maby fuel issue?!? But when it is missing it will pop and bang like it is getting fuel and it is just being dumped into the exhaust and burning once it is expelled. Any feedback would be much appreciated!!! Thanks!

 

[91gvr4gsr]

check the coil thats most likely your problem

 

[mikelv]

Any update?

 

[crazycoot80]

I did a differential compression check on my engine this weekend and the results are as fallows:
#1 = 77/80
#2 = 78/80
#3 = 78/80
#4 = 77/80
I tried to switch my wires like No Skills said to do but im confused... Do i just swap the plug end and leave the coil ends the same or what?? Because my #1 Wire is not long enough to reach #4.
And THANKS to ArticNemesis for that link! It was very informative!!! And my problem sounds like and issue with the swap because i do have a 1gCAS and replaced it when i replaced the head and dident re-time the engine, just put it back in the same position as the old one and it did not missfire before the head swap.
Thanks again for everyones help!!!!!!!!!!

 

[mikelv]

I did a differential compression check on my engine this weekend and the results are as fallows:
#1 = 77/80
#2 = 78/80
#3 = 78/80
#4 = 77/80
I tried to switch my wires like No Skills said to do but im confused... Do i just swap the plug end and leave the coil ends the same or what?? Because my #1 Wire is not long enough to reach #4.
And THANKS to ArticNemesis for that link! It was very informative!!! And my problem sounds like and issue with the swap because i do have a 1gCAS and replaced it when i replaced the head and dident re-time the engine, just put it back in the same position as the old one and it did not missfire before the head swap.
Thanks again for everyones help!!!!!!!!!!

Are you saying the compression is like 77-80? That's not good man unless I'm interpreting that incorrectly. How did you conduct the compression test?

From what I know, it should be closer to 180 on each cylinder.

I am thinking if this is correct, you could be running the car with the timing one tooth off. If this is the case, it will run, and run like shit until eventually you bend the valves enough that it won't run at all.


As for what we were talking about with the wires. You can switch at the coil, it doesn't make a difference. Just trace the #4 cylinder and the #1 cylinder and switch the wires at the coil pack.

All we were saying is if you switch them, and it does the same shit on the #4 instead of the #1 (#1 stops misfiring & 4 starts misfiring) then we know it's something with that spot on the coil pack.

Just to make sure you know, the #4 cylinder is the all the way to the left, and the #1 cylinder is the closest to the timing belt.

 

[crazycoot80]

I did a DIFFERENTIAL compression test. I am an Aircraft Maintenance Technician by trade and a differential compression test or a leak down test is what we use on piston aircraft engines and anything over 70/80 is good! The test is performed with a totaly different kind of gauge. The engine is placed on top dead center on the compression stroke of the piston you are testing. Then 80psi of air pressure is put into the cylinder and that is regulated by a regulator and is displayed on the first geuge so 80 is the reading on this gauge. The second gauge measures the amount of pressure actualy held in the cylinder and 78 or 77 is what was read on this gauge.

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[MrBoxx]

The best way to get rid of that Limp Mode issue is with DSMLink, where you can simply remove the check for misfires. I had to do this with my car, but didn't know that until I was moving from Wisconsin back to Michigan. I had to turn back after 10 miles because of it and look for the reason why.

I wish there were an easier way to get rid of the misfire, but Link is probably the best.

 

[mikelv]

Oh, okay great man, that's some awesome information. I was kinda worried for a minute.

Sorry my bad, I misread your posting there.

Okay, well I guess we know there isn't any problems going on there.

When you get a chance switch those wires around and we'll see if the misfire occurs on #4 as it did on #1.