81_vette!

1977, 4 speed manual. HEI, Edelbrock carb. Headers to true duals, no cat. Has been backfiring since I purchased it 3 months ago.


The backfiring is not the "shotgun" sound, but the "popping, gurgling" kind of sound...

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The car is constantly backfiring when you are either engine braking or coasting and in gear.
Does NOT backfire when idling or accelerating.

I just finished a complete, major tune-up and it is backfiring more than ever. I think the backfire is coming from the tailpipes.. not the engine compartment.

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My question is:

Is the backfiring related to the "custom" exhaust/pipe work?

or

Does it point to the car having fuel/air and timing issues?

Duke94

This has come up many times before. Here's a link to a good thread on the subject.

Gary

http://forums.corvetteforum.com/c3-t...tion-lars.html

forvicjr

check your exhaust for leaks.

lars

The thread referenced by Duke94 tells you most of what you need to know - your exhaust mods have caused a lean condition, so you need to richen it up.

As a matter of terminology:

Popping up through the carb is known as "backfire."
Popping out the exhaust is correctly termed "afterfire."

You don't have backfire - you have afterfire caused by a lean condition from your exhaust mods.

Lars