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

z28 suddenly quits

Old 04-06-2018, 04:43 PM
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Unhappy z28 suddenly quits

My 1994 Z28 very suddenly just quit running as if it ran out of gas. I waited about 15 minutes and it started like new again. I drove 2 miles and it just quit again. The electrical system is strong but it just won't start . It seems like it's not getting gas. What could it be? fuel pump ?
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Old 04-06-2018, 09:16 PM
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Re: z28 suddenly quits

It could be the fuel pump, but the only surefire way to check that is with a fuel pressure tester. Most likely it is your optispark going out. Mine did something very similar when it went out.
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Old 04-07-2018, 08:50 AM
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Re: z28 suddenly quits

Unfortunately, “Site Help and Suggestions” is not the place to post tech problems with your car. I'll move this to “LT1 Based Engine Tech".

You might also want to scan it for codes. Heat soak can affect the ICM or the cam position sensor in the Opti.

Last edited by Injuneer; 04-07-2018 at 08:53 AM.
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Old 04-07-2018, 11:50 AM
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Re: z28 suddenly quits


first thing you want to do is check fuel pressure. Ideally with a gauge with a hose long enough so you can tape it to your windshield. Fuel pressure may test good initially so watch the gauge when the car dies to rule in/out fuel delivery as the problem

If FP is OK, move on to ignition. ICM is suspect as they often fail once hot. Some auto part stores can test them...but testing them cold can show they work so not accurate in a "working condition".
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