I'm trying to track down a idle problem with my 1989 4.0L. I know its something within the electrical system. My jeep has a jumpy and inconsistent idle. I have replaced, adjusted, and tested everything else in the system (TPS, IAC, ICM, etc.) All of them are either new, or tested out fine so i am currently checking all the grounds because we all know how much the renix loves a good ground. All my grounds are clean, and show very little resistance. I then proceeded to check the wire resistance of the two grounds on the engine block. One showed very little resistance, and the other (i'm guessing the ECM ground) is showing 10.5 ohms of resistance. I am wondering if that high of a resistance for a ECM ground is normal, or if this is a issue? Thanks

 

Not sure on the resistance, but i replaced all my grounds on my Renix, when i first got her, and it sure cleared up the idle/stalling issue.

 

What do you mean by replaced? Did you replace the entire wire from the ground to the ECM?

 

yup, i had to replace it, it looked like someone or something had started to chew on it. I was just gonna piece it back together, but decided on running a whole new one, kind of a PITA

 

So in order to run a new one, should i just pull off the engine wiring harness and go all the way to the ECM with a new ground? Do you even have to go all the way back to the engine block? can it just be grounded to a ground under the dash?

 

What about vacuum lines? I just found a few leaks on my 88' and it is running loads better

 

There are no vac leaks. I have tested them all, and replaced most of the Vac harness.

 

Im sure you could, ground it somewhere else, i just decided to ground it in the same spot. It is a PITA, but im glad i re-did it.