OK, the problem wiht my car is that my #4 cylinder injector is not pulsing, and #3 and 7 are intermittent. They tried rotating them to no avail...That means it's either the PCM or the harness...Could a bad fuse(wither blown or damaged) cause this to happen?
And this would cause crappy idle and stumbling problems, right?


On a related note, how hard is it to change out the injector harness?

1995 Z28 .060 over LT4 with 306 cam & longtubes.

 

Anyone have any ideas?

Any help would be appreciated!

 

I would probably guess you have damage or a short in the wiring harness. Hopefully it didn't damage the PCM. Have you followed the injector wiring from the motor back to the firewall? One dead cylinder would definately cause poor driveability. I doubt it'a fuse, that would probably control all or at least one bank of injectors.

 

Yeah, it was kind of a shot in the dark with a fuse...Anyone have the harness P/N? And any other ideas?

 

probably just a bad injector

 

There is a device called a noid light that would help you troubleshoot this problem. You unplug an injector and insert the noid light terminals into the injector plug and crank the engine over. A flashing light indicates normal electrical pulses. Steady or no light indicates a problem with either the PCM or the harness. You could check each injector this way.

 

That was done this afternoon, it is not getting any signal at 4, and intermittent at 3 and 7.

I am really thinking it is the wiring, as the PCM was changed before tuning happened, and when it was untuned, it had very similar problems. It just used even more gas than now.

 

Had it happened to me. #7 injector wouldnt get signal from the PCM. I would swap Pcms with someone to double check.

If it works, then that means your PCM is no good and it cant be fixed. Well it can be but good luck finding someone to do it and for a right price.

Marcin

 

That may not be to easy...

CC306 with LT4 kit, A4, and .060 overbore...

Not exactly the easiest to find...

It was acting pretty much the same way on the way to get tuned...It just got a touch better...

 

umm...just put a stock pcm in there. My car runs pretty good on stock Pcm i dont see why yours wouldnt

Its worth a shot. You should be able to tell right away.
I sure did...with the injector gone, it was just dumping tons of fuel, u could smell raw fuel really bad, and the car didnt idle or drive good at all. With a stock pcm everyting went back to normal. No raw fuel and idled ok.

 

Well, that makes me think it is a harness issue, then. The PCM that I drove to the tuner with(the original) was replaced after the computer doing the tuning lost communication in the middle of programmin, and we had to use a different PCM. AS I stated, it didn't really change anything. Just less gobs of fuel in the functional cylinders.