Hi all:

My 93 Cutlas Ciera 3.3l V6 won't start. Gets some spark and fuel pressure is ok, compression in all cylinders is within tolerance. The problem started with the engine running extremely rough, like it wanted to tear itself apart and progressed to not starting at all. I initially replaced the crank sensor, seemed to make sense to me at the time, but still no difference. I ohmed the 4 lines from the crank sensor to the IM, tested ok and not shorts. My diagnostic readout wasn't working most of the time, SERVICE ENGINE SOON LIGHT would just flash consistently, forever, with no pause, it finally gave me a reading with an error code 42 (EST). I ohmed the 4 EST lines from the IM to the ECM connector, ok and no shorts. At one point, after a backfire, I got an error 42 and an error 34 (MAP), I shorted pins A and C on the MAP sensor and ohmed pin B to ground, got about 9.5v, haynes manual said it should be about 5v when not started. I had the IM and coil packs tested at Autozone, checked ok. I then, against my better judgement, replaced the ECM, used my old PROM, still the same symptoms. After more muddling I found that the only time I could get the OBD to work correctly, every time, was when the crank sensor connector was disconnected. When it is connected the fuel pump motor runs continuously, the air conditioner compressor clutch plate gets thrown out, the SERVICE ENGINE SOON light flashes constantly with no pause and at times there is a crackling noise coming from the housings for the fuel injectors, seems like all the injector switches are triggering even though it shouldn't be asking for fuel. I also checked, and in some cases adjusted, the pin connectors on all three ECM connectors. I visually inspected all the cable harness wires I could see, outside the casings and didn't see anything unusual.

Does anyone have any ideas as to what I'm missing or experienced something similar.

Thanks for any suggestions
tcrow :banghead:

Becareful with the ICM tests done at Autozone and such, disconnect the icm and see what symptoms you get, look for corroded connections at the icm connector, bad engine and or ecu grounds, suspect the icm here but go thru the checks first.

In addition disconnect the maf see what happens. Also do you have injector pulse with every thing connected properly?

Well, I found my problem. After exhausting all my troubleshooting skills, I decided to reinstall my original CPS and voila, the engine started immediately. Beware of new parts from autozone! In my zest to ohm every line, clean every connector and ground I must have inadvertently fixed my original problem without even knowing it. If I had been thinking clearly I would have changed the CPS much sooner seeing everything pointed to a retarded spark. Still don't understand why my injectors would fire constantly with the inadequate CPS but then, ignorance is bliss.

Thanks for your help.... :smile: