LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

No start after new PCM!!! why?

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Old Feb 16, 2007 | 03:22 PM
  #1  
tnmotown's Avatar
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No start after new PCM!!! why?

I had my PCM tuned and recieved it last night. I put it in here at work and the car started up, so i took it around the block to tested it out. I got it to 6000 RPM's now rather then 5000 RPM's as before. It seemed to drive a little better. When i got back to work i let it sit for a while and was washing it. When i went to go and start it, it would just crank but no start!! I smell fuel but not sure if getting spark. I put jumper cables to it and the 3rd time it started. So i switched PCM's back to stock and it still did the same thing. Would would be causing this? Maybe no spark? It drove fine when i put the new PCM in and took it around the block. Just now it doesnt want to start. Please help me out guys.....
Old Feb 16, 2007 | 03:35 PM
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check your PCM IGN fuse.
Old Feb 16, 2007 | 03:59 PM
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I would also check the connection be be sure nothing is bent or broken.
Old Feb 16, 2007 | 05:38 PM
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checked all the fuses. All are good. Checked the connections, everything tight and nothing bent or broken. It doesnt start with BOTH the new PCM and the old one. Someone said maybe the crank sensor? Im gonna try to get a scanner and see if any trouble codes come up.
What else should i try?
Old Feb 16, 2007 | 07:54 PM
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Crank position sensor would not cause a "no start" condition.
Old Feb 16, 2007 | 08:30 PM
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is the security light on while your cranking it?if so thats what it is.
Old Feb 16, 2007 | 11:38 PM
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ok so it wouldnt be the crank position sensor then if that would not cause a "no start".

The security light stays on for a couple seconds when i turn the ignition to on but then goes off and doesn't come on when i crank it over. I'm not sure what else to do
Old Feb 17, 2007 | 06:20 AM
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Releave the fuel pressure at the schrader valve. Then cycle KOEO and then off and do that several times. Then see if pressure is back up at the schrader valve.
Old Feb 17, 2007 | 10:34 AM
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how do i releave the pressure off the schrader valve? also are you saying to cycle the key to on and off several times? I'll fool around with it and see what i can do
Old Feb 17, 2007 | 02:46 PM
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Did you wash the engine?? If so you may have wet the opti.
Old Feb 17, 2007 | 03:36 PM
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FINALLY!! got it started. Had it towed to work and found a bad ignition module. It was getting no spark and the tech was testing the coil and stuff and found the module was bad. 5 minutes after replacing it, it started up. Part was free and gave the tech a free lunch. Thanks for all your guys help
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