I´m having this isssue, Spoolin up COP setup, changed spark plugs a few miles before, got injectors serviced and cleaned, and now the isssue is getting more often.

I´m driving and suddenly the car starts to sound like a subaru, one cilinder is not working, rev it a bit or after a few minutes and it comes back. Mostly low to medium revs, doesnt seems to do it on high revs. It is annoying.

Dont even now whats else to check, what sensor controls the ignition? don´t see anything weird on the scan gauge related to revs, ignition, injector pulse, nothing.

Anybody has has a similar problems? what should I check, no smoke, no codes.

Thanks for your help

 

Install factory coil packs and retest.
Your sure its a misfire and not a aputter like when a tps sensor has a dead spot?
And what plugs were used at what gap?

 

or if you dont have the factory coils you can test the coils you have with a multimeter

 

Will do! pretty sure it is a misfire, I was watching TPS on scan gauge and everything seemed correct

Plugs are NGK iridium at .22 gap

 

I have them, but also how do I test the coils with the multimeter?

 

this is how its done for the factory coils, you will have to do some google-fu to find the correct readings for your specific coils

 

A multimeter test can only tell you it's faulty.



What it can't do , just like all the other fancy tests is it can't tell you that it's NOT faulty.

 

dude are you high?

 

Actually, with coils, that can be true. What happens is the primary gets a break in it but maintains contact until the coil is heated by engine operation and expands, opening the circuit and suddenly no spark. If it cools off a few degrees, it works again.

 

yah finding thermal breaks is a pretty normal thing, its what heat guns are good for. I wouldn't even consider that fancy lol. I just fixed a board a couple weeks ago with a failed capacitor that needed a little blast with the heat gun to go into failure mode. So what im saying is if you can't find the problem by troubleshooting it just means you need to step up your game, not that it isn't possible to do. Thinking that just betrays a lack of technical knowledge.

 

Yeah heat, the other ingredient. I once had a radiator that would leave a puddle. At the radiator shop they could find no leak. It only leaked when warm.

 

Another thing, this being an 8 the computer from the factory came with a subroutine that played with the engine when it detected a misfire. It would shut of fuel to various cylinders looking for the source.

A few of the first 8's imported to the US came with a defective transmission that would mimic misfire (I got one of those). This invoked the Lemon Law a few times back when these cars were new.

Its possible with years and miles a good transmission with enough wear could invoke this subroutine if the subroutine is still there and allowed to run.

 

good thing we have J2534 because i have one of those early Evo 8's too. Do you happen to know which ROM ID that effected?

 

As per normal you've got no effing idea.


The normal failure mode for a coil is insulation breakdown which only happens under working conditions of 20 to 35 KV.


It's NOT heat either.


Wasted spark coils don't usually have that problem because the secondary side isn't earth return.
But it's "normal " for COP coils to fail that way.


That's why the Nissan RB crowd upgrade their ignitions using Mitsubishi wasted spark coils.

 

insulation breakdown would change the impedance of the coil..... once again your gonna claim that the engineers who made this stuff dont know what they are doing but you have the right answers.