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Oh, I feel sick. I may have scrapped my 94 over a CkPS!

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Old May 18, 2019 | 07:36 PM
  #1  
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Default Oh, I feel sick. I may have scrapped my 94 over a CkPS!

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....
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Old May 19, 2019 | 09:37 AM
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From: Prescott, Az
Year: 1990
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I'm tuned in.
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Old May 19, 2019 | 05:39 PM
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I'll probably hit it next weekend.
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Old May 19, 2019 | 08:04 PM
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From: Georgia
Year: 99 94
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Sounds more like a failing ignition coil.
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Old May 20, 2019 | 06:53 AM
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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.
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Old May 20, 2019 | 01:53 PM
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Engine: 4.0, new lifters valve job with new springs and exhaust valves, preload set with shims
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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.
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Old May 20, 2019 | 09:51 PM
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Engine: 4.0
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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.
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Old May 21, 2019 | 06:19 AM
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Engine: 4.0, new lifters valve job with new springs and exhaust valves, preload set with shims
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Originally Posted by BlueRidgeMark

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