Backfiring

[zimmy]

After changing my cam as part of an upgrade to a Weber 48 IDA set, I now suffer from consistent and major backfiring from the pipes whenever I am decellerating or just get off the throttle, even from a constant cruise. At first I was told it was from exhaust leaks, but I have fixed that area. Still no relief. In fact it may be worse recently. My cam builder was thinking that it may be a problem with the exhaust valves not closing fast enough or sticking a bit.

Has anyone had a severe backfire problem and were they able to solve it? How???

Thanks.
Zimmy

[427Aggie]

Zimmy,

What are the specs on the cam you changed to? Have you checked the plugs to see how rich or lean you are running.

I have the 48's on my car with a cam that is right at the edge...I got rid of the exhaust leaks and I know I am still running a little fat on the jets so I am going to lean it down until I find the perfect zone....I also get little puffs out of the carbs because of the size of the cam and that doesn't help.

Just puttering around town I pop constantly but I know there is a happy medium I just haven't found....

Again as I understand it backfire means fuel firing in the pipes.

Matt