Hi there I have a 92 Olds 88 that will Randomly die. When it dies I lose spark, I can get the engine going again by disconnecting the ICM and either reconnecting it or changing it with another used ICM i have. I have three used ICM all together and the car has died using all 3 of them, please note that none of the ICM'* are new but 2 are from the auto wreckers and one was in the car when i bought it. I have also changed all spark plugs and cables, and the water pump has been replaced. The car seems to die when its either been running for long dives 30mins plus or on really hot days. The car does get pretty warm but the temp gage never goes 1 or 2 bars over half. Also when i changed the water pump i cleaned both the Cam shaft and Crank shaft sensors. So now i have no clue what to try, i dont know if i should take the hit to the wallet and buy a brand new ICM or if i need to replace sensors, or if something is overheating. Any help would be greatly appreciated.

Well, I would rule out the ICM. The chances of all 3 doing the same thing is very very small. OK, so lets go over what you have. It dies, you have no spark. So that rules out spark plugs, plug wires, and coils. That leaves the LCM, which you proved is not the issue. So lets move on from there. Have you cleaned the ICM mounting plate? The ICM grounds to that, if corroded it will cause problems. next up, the CAM sensor, not likely. After that its the crank sensor, more likely. It'* not something you can clean. Testing it is a bit involved, I understand but have never done it, testing it with a DVMM, digital volt multi meter. Then watch for a signal to turn on and off as the engine turns over. But a oscilloscope is what is really needed. I would also inspect the ignition wiring harness for any frayed wires, shorts, or damage.

Yeah i used a wire brush and sanding paper to clean both the ICM plate and the underside of the ICM itself. The Strangest thing is the part where if after the car cools down and i unplug and replug in the ICM the car starts again. The wiring harness looks to be ok. As far as the Crankshaft sensor i have no clue on its condition, i know the wiring and the connection to the sensor was quite dirty due to the fact that the old water pump i had was leaking all over it and the camshaft sensor. So i clean the contacts and the wiring connection of both sensors and also removed the camshaft sensor and cleaned it.

Coolant on the wires can be a problem. However, seeing that it stalls when hot points me to a failing sensor, and back to the crank sensor. Keep in mind, diagnostics over the internet is not a exact thing.

I agree with the crank sensor diagnosis.

If it is one of the sensors shouldn't the car be sending me codes? I have done the paper clip trick and all it does is make the check engine light flash but no codes show on the car'* display.