It won't create a ground loop. I would test the quality of the ground first. Meter in DC volts, low range. Key in the run position, one lead back probes the ground wire at the ICM connector and the other lead on battery ground. What voltage do you get?

George

 

Checked today 31.2 mv went down to 31.0 in about a minute. That's just over a quarter volt. I'm sure it should be more then that ?

 

that’s 3 one hundredth or 30 thousandths of a volt which is an order of magnitude less than a quarter volt. That’s a very good reading and says that there’s nothing wrong with that ground. It also suggests, but does not entirely prove that your spark ground is good as well because they both have to pass through those rear engine block, ground attachment points.

George

 

So what do you suggest to look at next ? I mean that jokingly. I think we've covered just about everything 😅

 

Carefully cut back the electrical tape wrap on the wire loom that contains the white wire from the ECM to the ICM and inspect for corrosion/damage/shorts and look at the connectors at both ends.

George

 

So I've been doing alot of reading and thinking and here's what I came up with. I replaced the crank sensor 2 years ago and had a case relearn done then I was doing some reading and seen that you should see if the sensor was getting scraped and I can't remember if I looked at it before the case relearn or not but I did shim it because I seen a small mark on it. After reading that if the sensor was touched in anyway it would have to be relearn again. I'm thinking that I might have looked at it after the relearn was done and shimmed it. I'm not a 100 % forsure I removed it after the relearn but I might have. So I'm thinking all the misfiring I've had could have been from this ? A friend of mine has a scanner and I might ask him to use it and do a relearn again and see if it solves my problems. Do you think this could be a possibility for a p0351 code ? 🤔 But then I was having problems before I changed the crank sensor so I just don't know that would be the problem.

 

The conventional wisdom is that a crank sensor that does not have a proper relearn will cause improper calculated misfires, but not felt misfires. Do you feel these misfires at this point?

George

 

Yes I feel the the misfiring especially when I'm at a set of lights and when I excellarate I feel a studer. Today now that it's hot it's running poorly. I think it's fring the icm again. I have one more spare one in case I get stuck.

 

Did you open that wire loom between the PCM and ICM and inspect the wires as well as both connectors?

George

 

I opened the first 18-24 inches of it from the icm back so far. It's so hot here right now. I'm just waiting until we get a little cooler here and I'll take a better look at things.