exhaust popping

[TrcksR4ME]

Common problem here, rev up the truck to 3000-4000 rpm and when I let off I get the nice pop pop pop in the exhaust like small backfires but not a backfire. What causes this? I thought air leaks in the exhaust could cause this but if your running too rich will it also cause this problem? Working on exhaust issues the last few days and need to put in new gaskets for the headers and collectors, but if it still does this I want to know what to check next. TIA

 

[big83chevy4x4]

that is caused by bad header gaskets. almost garentee it wont do it after you put new ones on.

when you let off the gas, it had unburnt fuel in the exhaust, when the air from a bad header gasket get in, it ignites and thats the poping sound you hear. it doesn't do it when it reaches the end of the exhaust cause it cools enough that it won't

 

[TrcksR4ME]

cool, thanks /forums/images/graemlins/thumb.gif I figured it was something to do with the gaskets. But being engine dumb I wanted to explore other possibilities /forums/images/graemlins/grin.gif

 

[GMCLegacy]

lack of back pressure?

 

[lifethroughdeath]

big83 hit it on the head, when i installed headers last summer i forget to re-torque them after driving around for a while, and sure enough after i torqued them down no more "pop, pop, pop." But after a while it started up again, so i replaced the crap paper gaskets with dead soft aluminum gaskets, and now it's great /forums/images/graemlins/waytogo.gif

Nate /forums/images/graemlins/k5.gif

 

[TrcksR4ME]

Yeah, I definately need new gaskets, I was trying to reuse my old ones with a new(to me) set of headers. They are some composite material (forgot what brand) so I was hoping they would still work /forums/images/graemlins/whistling.gif Oh well