Light Backfire Through Exhaust
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Joined: Jan 2004
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From: Forney Texas
Light Backfire Through Exhaust
I am experiencing a light backfire through the exhaust when I get the car up to around 4k rpm and let off of the throttle. It does not last but a second and is not very loud. I have a modified top end (heads, cam, 1.6 roller rockers, super ram plenum/runners, long tube headers etc. and the car is a 90 L98 with 51k miles. When I installed the heads and adjusted the valves I was very methodical and followed the instructions for setting the lifter preload to the letter. I am thinking the exhaust valves must be open longer than they should be leaving me to wonder if they are adjusted too tight even though I really don't know how they could be.
Is there another cause for this problem? I set the base timing at 2 deg advanced over the factory setting with the EST disconnected. I also have a chip from PCMforless. As I said earlier, the sound level is so low that my wife hasn't mentioned hearing it. I just can't imagine if all things were working/adjusted properly that I should be getting any backfire at all.
All suggestions for where to look are appreciated. Also, give a mechanical reason for your recommendation so that I can learn something.
Thanks,
90Indy
Is there another cause for this problem? I set the base timing at 2 deg advanced over the factory setting with the EST disconnected. I also have a chip from PCMforless. As I said earlier, the sound level is so low that my wife hasn't mentioned hearing it. I just can't imagine if all things were working/adjusted properly that I should be getting any backfire at all.
All suggestions for where to look are appreciated. Also, give a mechanical reason for your recommendation so that I can learn something.
Thanks,
90Indy
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
It's quite possible that you're getting raw fuel into the exhaust. A leaky injector perhaps?
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Joined: Jan 2004
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From: Forney Texas
Originally Posted by Corvette Kid
It's quite possible that you're getting raw fuel into the exhaust. A leaky injector perhaps?
90Indy
