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

Starts, runs great, dies, won't start, repeat

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Old 06-08-2009, 02:36 AM
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Unhappy Starts, runs great, dies, won't start, repeat

The car mysteriously died on me one night after driving a few miles and would not restart. Had it towed home and tested a spark plug wire for spark. Got no spark. Next day, disconnected the Crane Hi-6 and it started right up. Drove it for a couple of miles and it died and would not start up again. Came home at night and just for kicks tried to start the car. Started right up.

It seems to die out on me after it warms up. Bad ICM?
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Old 06-08-2009, 12:55 PM
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coil, icm, opti seem to be the most common culprits.

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Old 06-08-2009, 12:59 PM
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sounds alot like what my car was doing
i tried just replacing the icm
no change
so then i nutted up and bought a new opti and coil
havent had a problem since
nock on wood

how many miles do you have on the car?
have you replaced your opti and coil before?
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Old 06-08-2009, 01:05 PM
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never replaced the coil or icm before.
125k miles on the car. Changed the opti twice.
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Old 06-10-2009, 01:33 PM
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I think it's the opti again. Not getting a signal on the white wire going to the ICM.
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Old 06-11-2009, 09:15 AM
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I have a reprogrammed obd1 pcm so it's not throwing any codes.

Could it be just a bad wire from the opti to the pcm?

I bought a ICM from Kragen and swapped it after the car died and it didn't help.
Of course, I just disconnected the connector and connected the new ICM just hanging there. Did the back of the ICM have to be grounded?
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Old 06-11-2009, 09:24 AM
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opti
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Old 06-12-2009, 05:34 AM
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Why are you swapping parts without doing measurements

Or at the very least get out the hair dryer and warm some things up.

Last edited by Guest47904; 06-12-2009 at 01:48 PM.
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Old 06-12-2009, 05:50 AM
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Car would run for 10 mins and die. After it died I swapped the ICM to see if a known good ICM would start it back up. Since it didnt work I returned it.

I had a extra PCM laying around so I swapped that too. No change.

I measured the white wire and got no voltage.
On the distributer harness I got the correct values on A, B, C and D was to ground.
Which leads me to believe it's a bad opti. I also got codes 16 and 41 EST open.
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Old 06-12-2009, 11:46 AM
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Originally Posted by Hood_Lum
Car would run for 10 mins and die. After it died I swapped the ICM to see if a known good ICM would start it back up. Since it didnt work I returned it.

I had a extra PCM laying around so I swapped that too. No change.

I measured the white wire and got no voltage.
On the distributer harness I got the correct values on A, B, C and D was to ground.
Which leads me to believe it's a bad opti. I also got codes 16 and 41 EST open.
I have code 16 and 41 and im in the same boat with you as far as dying after it heats. Im changing the opti tomorrow so ill llet you know how it goes
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Old 06-13-2009, 03:14 AM
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So I swapped the opti and the cars running.
But now it doesnt feel as powerful as before so I plugged in my laptop.
I got the trouble code 49. Something to do with the MAF.
Anyone have any info on this trouble code?
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