LT1-LT4 Modifications 1993-97 Gen II Small Block V8

PCM problems

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Old Oct 18, 2011 | 10:54 AM
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Default PCM problems

I was driving the car the other day in the rain, I stop to get a rain jacket and when I came back to start the car it started and idled at 500 rpms then died. I got the car back to the shop and replaced the opti with an AC Delco opti, the car ran great for about an hour, and then reverted back to the previous symptoms. We found out that there was no injector pulse on every other injector, could this be a bad PCM?
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Old Oct 18, 2011 | 11:02 AM
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That's not good... Did you check the opti harness??.. Pm'd you..
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Old Oct 18, 2011 | 11:16 AM
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Originally Posted by defaultexistence
That's not good... Did you check the opti harness??.. Pm'd you..
The opti harness was checked and is good. We have tried three optis all AC Delco’s and they all are bad within one hour of running the car. I just wanted to confirm that it was the PCM before i called to complain, and it not be the problem.

I have an extra PCM but with no tune it doesn’t do me any good
Thanks tho
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Old Oct 18, 2011 | 11:22 AM
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Originally Posted by 95sscamaro
The opti harness was checked and is good. We have tried three optis all AC Delco’s and they all are bad within one hour of running the car. I just wanted to confirm that it was the PCM before i called to complain, and it not be the problem.

I have an extra PCM but with no tune it doesn’t do me any good
Thanks tho
From you build sig, I see you are still running stock injectors so you can at least try the spare pcm to see if the car runs.
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Old Oct 18, 2011 | 11:41 AM
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Car has SVO red tops #30 injectors

We used a power probe and there is no power coming from the PCM on those injectors
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Old Oct 18, 2011 | 12:07 PM
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FWIW....I drove through a HUGE puddle (probably a foot deep on the passenger side) during a rainstorm in my 99 Firehawk and apparently got the PCM wet....all sorts of lights were coming on on the dash and it died a couple times on the road....2 days later it dried up and everything was back to normal like it never happened
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Old Oct 18, 2011 | 02:38 PM
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A bad coil can cause no injector pulse
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Old Oct 18, 2011 | 04:05 PM
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Originally Posted by 96TransAmboosted
A bad coil can cause no injector pulse
yea but 4 out of the 8 have a pulse, PCMforless is going to put the same tune on the spare PCM that I have for free, so now all I have to do is wait and hope that this fixes the problem.
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Old Oct 18, 2011 | 04:36 PM
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Originally Posted by 95sscamaro
Car has SVO red tops #30 injectors

We used a power probe and there is no power coming from the PCM on those injectors
That's because power does not come from the PCM. It comes from the fuse. Ground comes from the PCM. Have you checked your injector fuses? There are two and each supplies half of the injectors.
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Old Oct 18, 2011 | 05:32 PM
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Originally Posted by shbox
That's because power does not come from the PCM. It comes from the fuse. Ground comes from the PCM. Have you checked your injector fuses? There are two and each supplies half of the injectors.
No I didnt, i will have to Check them tomorrow
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