1998 Pontiac Sunfire won't start!


FiveByFive
09-26-2012, 04:22 PM
Hello everyone!

I'm hoping to get some ideas that will solve my problem. Several weeks ago I was on the interstate and my usually reliable Sunfire died on me. Could not restart it and had it towed home. My dad, who's an old-school mechanic and car enthusiast, advised me that it could be one of 3 things: lack of spark, faulty fuel pump, or timing chain.

We basically ruled out the timing chain because he said that if the timing chain broke then the car wouldn't sound normal when trying to turn it over, which it does. I then got the ignition module tested, it was good. That left me with the fuel pump, which I purchased @ $250. We put it in, along with a new fuel filter, and it still wouldn't fire up.

I then looked in my repair manual that had suggestions for the symptom of "engine turns but will not start up". Everything seemed ruled out except for "faulty crankshaft sensor or faulty PCM". Replaced the crankshaft sensor (which I know has to be relearned but you have to start the engine first) and I got 3 PCMs off similar year and model cars in a local junk yard. Still nothing.

I know you have to reprogram the PCM after you replace it, but will an un-reprogrammed PCM cause the car not to start? And will a dead PCM cause a car to die in the first place? Otherwise, anyone have any other ideas I can try? Thanks so much in advance!

jdl
09-26-2012, 04:43 PM
You should have visually check for spark at the plugs before you did anything. Were there any applicable trouble codes, before you worked on it? At the least you need an obd 2 code reader to check codes.

If you had spark at the plugs then use a gage and check fuel pressure.

If the ignition module assembly sits right on top of spark plug makes it a little awkward to check for spark, still possible. Turn assemble upside-down, use spark tester in boots, ground tester to engine metal, crank engine should see spark at tester.

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