View Full Version : Backfiring on decelaration


camaromaniac68
Dec 10th, 02, 05:00 PM
Help. I hava a 68 camaro with a 72 350 ci and a quadrajet. I just put a hei distributor in to relieve backfire thru exhaust but to no avail. I have the stock exhaust manifolds and have a moderate exhaust leak in exhaust pipe about 12" past exhaust manifold. Timing is @ 6 btdc. ANy ideas? Thanks, Jim.

1 2RUN
Dec 10th, 02, 06:35 PM
Your problem is the exhaust leak near the manifold. I had a donut gasket on the manifold on my truck leaking and it blew the muffler in half. The leak lets air into the exhaust pipe and the slightest spark from the exhaust port on deceleration turns your pipe into a cannon.

------------------
'69 RS Camaro
355 5-speed 4.11

Everett#2390
Dec 11th, 02, 06:52 AM
Carb running alittle rich?

Turn down idle mixture screws 1/4 to 1/2 turn, lean the mixture out.

------------------
Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"

camaromaniac68
Dec 11th, 02, 05:05 PM
I thought it might be the exhaust leak, thanks alot for confirming,I'll lean out the carb too.

Snatchin'gears
Dec 11th, 02, 09:56 PM
Have a vacume gauge to read the manifold preasue reading. Tune mixture or mixtures for max vacume effect at idle.