gip63
Forum Regular
Posts: 257
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Post by gip63 on Dec 21, 2014 22:15:14 GMT -5
What would be the main causes of backfires when you are under hard acceleration? I'm wondering if I have carb problems or timing problems. It seems to run ok till you haft to give it a lot of gas. Thx for what ever help you give.
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Post by odzking on Dec 21, 2014 22:38:48 GMT -5
Is it a ThermoQuad?
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gip63
Forum Regular
Posts: 257
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Post by gip63 on Dec 22, 2014 13:21:33 GMT -5
750 cfm edelbrock on top of a 440
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Post by 72sunroof on Dec 24, 2014 20:55:12 GMT -5
Check for vacuum leaks, use water sprayer or wd40. No leak do next steps. If timing good all in mechanical then carb is going way lean. Give it more accelerator pump, slow down secondaries and if still there jet secondaries.
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Post by 71se3834v on Dec 24, 2014 22:52:57 GMT -5
You might want to start with the basics. Do a compression check and get a vacuum reading and check the timing. Is this a misfire or an actual backfire?
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Post by robertsrt on Dec 25, 2014 10:07:44 GMT -5
99% of the time backfire is timing related. I would not suspect the Edelbrock as its a vacuum-assisted secondaries carburetor. If it were mechanical secondaries, those CAN backfire if opened too soon, on auto trans cars, but that's not your situation. For sure what the others have said - check the basics, then tune the carburetor
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gip63
Forum Regular
Posts: 257
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Post by gip63 on Dec 25, 2014 17:27:55 GMT -5
Thanks for help guys, I turned timing back just a little and it seemed to solve problem, that was the quickest thing to try. The carb has not been a problem so far but these cars need attention all the time so you never know.
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