Cadillac Seville / Cadillac Eldorado Forum Discussion, Looking for help from mexico - hard starting in Past Cadillac Vehicle Discussion; thanks rodnok, very good info. i see that the voltage of these things gets as high as 100V, that even ...
Automobile(s): 1996 El Dorado and 1991 Cheyenne Pickup
Puerto Escondido, Mexico
Re: Looking for help from mexico - hard starting
thanks rodnok, very good info. i see that the voltage of these things gets as high as 100V, that even might hurt if you stick your tongue in there
would be interesting to know the voltage of each sensor with the engine idling, didn't check, just cranking... still don't know if the two types of sensors cause this issue, but as far as i can see it's the only thing to check on right now.
If one CKP or the CMP is faulty and is setting either circuit or signal codes the ignition system will default to "limp home" mode - a fixed 10° BTDC timing setting: The engine will run, but with reduced power and performance. The two CKP's are spaced some number of degrees apart as they sense the reluctor wheel teeth, so the two CKP's send a comparison signal to the PCM for ignition and injector timing input. The CMP is a cylinder (piston) TDC reference. For a more detailed explanation and the full operation of all the ignition/injector sensors, read the chapter in the GM service manual for your exact year/model.
The ignition system supplies a 12 volt reference signal across the CKP coils and the reluctor wheel induces an ON/OFF pulse at passage past the CKP permanent magnet, thus generating a rotation (degree) pulse 24 times each crank revolution.