C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

C4 Hot Start Problem

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Old Jun 9, 2025 | 12:44 PM
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Default C4 Hot Start Problem

I have a 1992 C4 that runs great. However, if I drive it so it reaches normal operating temperature then stop, it won't start again until it cools down. Once started it runs perfect again.
I have replaced most of the electrical and electronic parts except for the ECM. I'm a fairly good mechanic and I have a background in electronics but I am stumped so I took it to the only mechanic I trust.
He spent three days on it and could not locate the issue. He did discover that when it is hot and won't start there is no spark. So, it's been on non op status for 2 years which is sad.

If anyone has any suggestions I would really appreciate your input.

Thanks,
Ray

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Old Jun 9, 2025 | 12:49 PM
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Maybe fuel injectors swollen from heat nd short when fully hot?
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Old Jun 9, 2025 | 12:54 PM
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Have you changed out the Optispark?
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Old Jun 9, 2025 | 01:27 PM
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I assume you replaced the ICM which is know for this. If the mechanic spent 3 days on it did he confirm it was losing spark when hot? Dan
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Old Jun 9, 2025 | 10:00 PM
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Thanks, I'm not certain that I changed the fuel injectors. I'll check on that.
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Old Jun 9, 2025 | 10:03 PM
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Thank you, i did change the ICM. The mechanic verified there was no spark when it wouldn't start.. Frustrating!
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Old Jun 9, 2025 | 10:05 PM
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I did replace the optispark with and I didn't cheap out on it so it should be okay.
Thanks!
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Old Jun 9, 2025 | 10:16 PM
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The amount paid for an optispark has little to no connection with it's reliability. Dan
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