1977 Backfiring constantly...
Thread Starter
Racer
Joined: Oct 2007
Posts: 270
Likes: 0
From: Chapel Hill NC
1977 Backfiring constantly...
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...
**************************************
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.
****************************************
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?
The backfiring is not the "shotgun" sound, but the "popping, gurgling" kind of sound...
**************************************
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.
****************************************
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?
Last edited by 81_vette!; Jul 9, 2010 at 09:13 AM.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
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
Gary
http://forums.corvetteforum.com/c3-t...tion-lars.html
Tech Contributor
Joined: Aug 1999
Posts: 14,369
Likes: 6,361
From: At my Bar drinking and wrenching in Lafayette Colorado
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
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
