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  #1 (permalink)  
Old 03-08-2018, 09:44 AM
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Default Backfiring on deceleration

When letting off the gas, decelerating, my 351W backfires through left exhaust only. More of a popping sound and not really annoying, but just concerned I might be damaging something in the engine. Any suggestions as to how to stop it?
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  #2 (permalink)  
Old 03-08-2018, 09:47 AM
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That's almost always an air leak around the collecter/primary pipes/etc. use the Acousti-Seal that is giving fits in this current thread: Removing side pipes
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Old 03-08-2018, 09:56 AM
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Thanks Patrick
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Old 03-08-2018, 10:21 AM
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Ck for exhaust gasket leak or intake leak also. l
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Old 03-08-2018, 10:32 AM
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I've tightened all of the accessible exhaust manifold bolts, but unfortunately, most are very difficult to get to, even from the underside when on a lift. At this time, the issue is not bad enough to start removing manifold to check for intake leaks. At this point, I think I'll try the header to side pipe joint first.
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Old 03-08-2018, 11:01 AM
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Sometimes it is a lean condition. Easy to check and it is reversible. Try richening up the idle mixture just a touch. If it is a standard Holley style carb, turn all (2 or 4) idle screws counter clockwise by 1/8 of a turn. If that doesn't fix the popping on decel, put them back where they were and work on the pipes.

Last edited by Texasdoc; 03-08-2018 at 11:06 AM..
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