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I have a 88 cavalier with a 3400 out of a 99 grand am. I am using the stock cavalier wiring. My isue started last summer when the car died blew the pcm/fuel pump fuse. so i replaced the fusetried to start the car it blew the fuse again so i checked some wiring fixed grounds and replaced the pcm that fixed the fuse blowing problem. I then tried to start the car it turns over sputters and then backfires out of the intake. I replaced the plugs they were wet, checked timing (lined up), fuel press is good, compression is good, crank sensor is brand new. I hooked it up to my pico scope to cyl 1 and 6 and i believe crank signal disconnected my injectors and pcm turned the car over and found in the wave form that it fires a few times where it should and other times 60 to 180* out. Which made me think my icm is bad but i have tried a known good one from another grand am and nothing happened. I was wondering if anyone had any ideas or simular problems before i waste money on a icm. thanks
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Sounds like to me you have a security problem. Turn the switch to the on position and see if the security light flashes, if it does leave it in the on position for no less than 11 minutes, then turn it to the off position, then try to start the engine. If it doesn't work the first time, try it again. This is time consuming, but I went through this with my friends Grand Am. I thought he had a bad ICM too until I remember this same problem I had with an Olds Alero a few years back and this solved the problem. Good luck. -
Theres no securety feature on the car im using the 88 cav wiring harness. thanks thoughComment
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