My 92 Lesabre was stalling at random moments on the highway, then not starting for 5 or 10 minutes. To make a long story short, I ended up installing a new crank position sensor, a used ICM from a 91 Lesabre and the ECM & PassKey 2 module from a 93 Bonneville. I inserted the appropriate resistor to make the PassKey 2 system work by measuring the resistor on the ignition key for the Bonneville. Now, the car will start and run, but the "Check Engine" light is always on. I think that is because my 92 Lesabre doesn't have an EGR, so the ECM from the 93 Bonneville (which has an EGR) thinks there is a problem. I don't mind having the Check Engine light on, but the car has one other problem... When you start the engine hot, it coughs and shudders until you rev it up for a few seconds, then it runs normal. (This doesn't happen on a cold start.) I have tried putting the old ECM back in, but then the car just starts and runs for about 1 second. Should I try putting the memcal from the Lesabre ECM into the Bonneville ECM? If I do that, do I have to put the original PassKey 2 module from the Lesabre back in (and the resitor to match it)? My wife is really gettin on my case... need solution...I don't have much experience - just trying to figure this out as I go along...HELP!

Nice to have ya LJH

welcome to the forum. good luck with your ride....

Moved to proper area for better visibility.

Not sure what you mean by "Stock?"... All of my cars (and parts cars) are just regular vehicles with no modifications for performance.

welcome to the site. the security module puts out the same signal to the pcm if its happy. both pcm'* are looking for the same signal.

Thanks JWFIREBIRD. If the car will start and run for about 1 second with the original Lesabre PCM plugged in, does it mean that PCM is faulty? I tried putting the memcal from the Lesabre PCM into the Bonneville PCM, but if I recall correctly, it started and ran for 1 second then too... And for some reason, I have the feeling that if I restored the original PassKey 2 module and plugged in the original PCM, it would start and run like normal. How can this make any sense?

either pcm should work with the original vats module, its just looking for a 30Hz signal.
http://www.3rdbrakeflasher.com/docum...ass_Module.pdf

i dont think security is your issue. i think those years wouldnt allow the car to start at all. if it was the security light would be flashing.