BlueRidgeMark

5 or 6 years ago (?), after not being able to solve an ECM problem, I gave up and replaced my 94 with a 97 (which I totaled last year thanks to a Suburban). It would die, and not start until it cooled down. Tried 3 new ECMs from an eBayer who had a great reputation, and was really great to work with. Nothing worked. I thought I had it narrowed down to a heat issue on the ECM, because packing it with ice would bring it back to life after 10 or 15 minutes. I limped home that way a few times.

Parts of that 94 went to various members of this forum. The right rear frame rail went into my 97. (It was badly rusted out and unsafe. I cut it out and spliced in the piece from the 94. Came out great, really.) Then the rest went to the scrapper last year. I still have the engine and transmission. HINT!

For some reason, this morning I got to mulling it over, and realized, it may have been the CkPS all along. I ruled that out early on because I had just had it replaced a few months before. But the shop I used would probably have used an aftermarket part, so...

So, maybe I could have driven that $1,000 dollar 94 for a few more years, or maybe still be driving it.

I think I'll pull the CkPS off that engine and test it.... just to torture myself....

cruiser54

I'm tuned in.

BlueRidgeMark

I'll probably hit it next weekend.

MonacaYankee

Sounds more like a failing ignition coil.

BlueRidgeMark

It' been a few years, but I"m pretty sure I had replaced the coil not long before the problem showed up. Maybe a few months before. NAPA part.

97grand4.0

Maybe, but I had that happen with the cam sensor, not the crank sensor. Would drive ok to my destination then not start. No code.
I am seriously considering investing in a scope. PICO's are about 1000 but man, are they sweet. Displays every waveform in real time. Injectors, cam and crank sensor, you can really spot a bad one.

BlueRidgeMark

Hmm. Yeah, at the time, I didn't know about the cam sensor. Then had a problem with it on my 97 and got edumacated. Dizzy bushings were shot and the cam sensor was getting whacked. Learned a bunch with that adventure.

I knew the problem was heat related, and I started icing things, different things. I got good results when I iced the ECM, so I made a big mistake - I stopped looking for the problem.

That icing of the ECM could easily have coincided with the faulty part cooling down enough to work.

97grand4.0

Yup. Mine would then restart after it sat a little while and after a few cranking sessions. It was aftermarket, had just replaced it 2 weeks prior. So replaced the dizzy, which had another aftermarket. Lasted another 2 weeks then same issue. So went to the boneyard and grabbed a mopar. That was 3 years ago, nary a problem since, I think.