Big Problem
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From: SOUTHERN ILLINIOS
Big Problem 95 LT1 T/A 6 SPEED , DOES ANY ONE HAVE ANY IDEAS ABOUT A BOX THAT RUNS THE ELECTRICAL ON THE CAR BESIDES THE PCM AND THE FUSE BOX , CHANGED THE OPTI CAR RAN ABOUT 10 MILES THEN JUST SHUT DOWN THEN CAME BACK ON THEN I STARTED IT THEN IT SHUT DOWN AGIAN , WILL CRANK NO SPARK GETTING FUEL AND THE SECURITY LIGHT IS NOT FLASHING.... I HAVE CHANGED ICM , COIL PLUGS AND WIRES.. I AM AT THE END OF MY ROPE WITH THIS CAR , CAN ANYBODY HELP 
It's a long shot, but try switching the pcm relays in the fuse box with one that's not needed. If a relay is failing, it could be heating up and shutting down. Just an idea, and it won't cost anything. Other than this, I would say point to the pcm. In a situation like this, double check all of your grounds on the motor to make sure the pcm is being fed enough voltage. Just a thought.
Originally Posted by RAREBREED95
hey guys if i have a break in the positive cable would it make the car do that. it seems like a ground to me though.
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I think he meant the wire covering was missing cuz a complete break in the hot cable would mean no voltage. Surely someone with cut wires would know what the problem was!
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Originally Posted by RAREBREED95
hey guys if i have a break in the positive cable would it make the car do that. it seems like a ground to me though.
Def. check all positive and negitive connections comming off of the battery. I had a very close problem, where the car would start sometimes purfect and not even turn over others. Then one day I was just driving down the road and the car lost all power. It turned out that the positive connection going from my battery to the aternator had worked its way loose.
Joined: Nov 2001
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From: LT1 land...the "409" of the 90s!
check those things.
THEN hook up a scanner and look for the correct opti Siganls. We have new optis bad, but if this was the same issue as before I would rule it out and check wires.
Years ago one of the local cars was having this problem under warranty. In the end they replaced the opti and opti harness. If the opti does not send the correct signal it fuel pump shuts off. The dealer had the car four or five times over a month period. The last time they had it four two weeks. He got a block and had to walk back to get a ride to work
They had replaced the Fuel pump ,Fuel pump relay ,wiring and fusable links. It came down to the opti not making a good connection
BTW the main PCM power runs from the PCM fuse scross the front of the car to the C100 connector to the PCM. Check the connector for signs of corosion or damage. the mak sure the gruods are all good. If I remember right there is a KEY gruond just above the starter from the PCM to the Block as well as three on the ICM. One of those goes to the chassis
BTW NEVER rule out a bad battery or alternator
Good luck!
THEN hook up a scanner and look for the correct opti Siganls. We have new optis bad, but if this was the same issue as before I would rule it out and check wires.
Years ago one of the local cars was having this problem under warranty. In the end they replaced the opti and opti harness. If the opti does not send the correct signal it fuel pump shuts off. The dealer had the car four or five times over a month period. The last time they had it four two weeks. He got a block and had to walk back to get a ride to work
They had replaced the Fuel pump ,Fuel pump relay ,wiring and fusable links. It came down to the opti not making a good connection
BTW the main PCM power runs from the PCM fuse scross the front of the car to the C100 connector to the PCM. Check the connector for signs of corosion or damage. the mak sure the gruods are all good. If I remember right there is a KEY gruond just above the starter from the PCM to the Block as well as three on the ICM. One of those goes to the chassis
BTW NEVER rule out a bad battery or alternator
Good luck!
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Teching In
Joined: Oct 2005
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From: SOUTHERN ILLINIOS
i checked the opti harness , the plug that hooks in the opti looks a little corroded i bought some elec. cleaner and used a wire to clean i allso n oticed that the rubber grommet is not on the plug it seem to be loose in the opti. .where can i get a new harness oor plug.. i tried to start the car by wiggling the plug and cranking it over . still nothing . it will crank thats it .the grounds look fine...