Thread: engine backfire out exhaust

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possibly vacuum leak, or leak at headers, sucking air in also.... sometimes a small leak in the exhaust system will suck air in and cause what sounds like a small backfire

Are you running lean?

-Chris

If you're 100% sure you've got the drive gear on the distributor lined up right, start checking the carb. Since you stated that it happens every 2-3 seconds, that indicates that fuel is pooling in the exhaust and lighting off.

Pull the plugs and check the color of the tips. They should be brownish to reddish-brown. If the plug is wet or really dark, you're running rich.

What is your fuel pressure? The Street Avenger uses 5-7psi.

Also, you didn't say if this happens at just idle or under acceleration or under cruise or all the time.

Is the distributor vacuum advanced? If so, make sure you've got it connected to the right port on the carb. The Street Avenger has 4 ports and each one is specific for each application. The port for vacuum advance is just to the right of the electric choke, just above the idle mixture screw.

Start with that and get back to us letting us know what you've found.