72 LT1 dies on acceleration

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Nov 13, 2021 | 06:09 PM

ray3222

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72 LT1 dies on acceleration

72 LT1 idles fine. On acceleration the car jerks with thumping sound & dies. Fuel pump, filters, plugs seem ok. 90,000 mi. Thanks in advance.

Nov 13, 2021 | 06:52 PM

Dirty Dalton

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From: Persona Non Grata

2022 C3 of the Year Finalist - Unmodified

Sounds a bit like mine when the accelerator pump took a vacation. Mine was also extremely difficult to start.

Nov 14, 2021 | 12:09 PM

Mrvettenick

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With then engine off, look down the carb while moving the throttle, you should see fuel being streamed out of the nozzles. If so, then your accel pump is OK.
If that checks out, then the next item to check is your vacuum advance operation.

Nov 14, 2021 | 07:55 PM

Rescue Rogers

Is my vette stock?? HAHA

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2020 C3 of the Year Finalist - Modified

2020 Corvette of the Year Finalist (performance mods)

2019 C3 of Year Winner (performance mods)

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I second timing and vacuum advance. Any work done latley? IS it a stick or automatic? Vacuum leaks?

Nov 15, 2021 | 10:01 AM

fstntq

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From: Portland, the original!

Does the engine do this while revving, i.re., while the car does not move, or just under vehicle acceleration? Items you mention just "seem OK" or known OK?

Quote:

Originally Posted by ray3222

72 LT1 idles fine. On acceleration the car jerks with thumping sound & dies. Fuel pump, filters, plugs seem ok. 90,000 mi. Thanks in advance.

Nov 15, 2021 | 03:33 PM

L-46man

Melting Slicks

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From: PHX AZ

Check float level and needle seat.
Check fuel pump pick-up in the tank. Should be at the bottom of the tank with a little CLEAN sock on it.

Nov 15, 2021 | 09:17 PM

ray3222

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Engine revs to high rpms standing still. Upon acceleration a loud thumping sound comes from inside engine & car dies. It sounds major to me. Thanks.

Nov 15, 2021 | 09:25 PM

Chambered

Race Director

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From: Milford Michigan

Quote:

Originally Posted by ray3222

Engine revs to high rpms standing still. Upon acceleration a loud thumping sound comes from inside engine & car dies. It sounds major to me. Thanks.

Maybe a backfire through the carb???

Try advancing the timing a little & see if this solves it. This happened to me back in the 70's on a Cuda after my Uncle & I drilled out the check valve hole on a Holley to open the secondaries faster. First test drive it fell on its face upon sudden acceleration. We loosened the distributor & bumped it a few degrees & that solved it.