Backfiring 86 F150
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Joined: Nov 2007
Posts: 22,415
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From: Denver Metro Area, CO
86 straight 6, I'm gonna assume a non-feedback carb. In general, backfiring is a
symptom of late ignition; rather than the explosion being contained in the cylinder
and pushing down on the piston, the explosion is partially happening in the exhaust
system (or, worse yet, up through the carburetor). I would start with the basics -
cap & rotor, plugs, ignition timing, then move from there. I've caused backfiring on
deceleration by wildly misadjusting my carburetor. There are also some emission
control devices that are designed to prevent the occurrences I caused myself so
your true problem could lie there, too. You might also make sure your EGR valve
isn't stuck but such situations are generally accompanied by a rough (sometimes
exceedingly) idle.
You might also ask your computer for any codes (if you've got one).
-chris
colorado, usa
symptom of late ignition; rather than the explosion being contained in the cylinder
and pushing down on the piston, the explosion is partially happening in the exhaust
system (or, worse yet, up through the carburetor). I would start with the basics -
cap & rotor, plugs, ignition timing, then move from there. I've caused backfiring on
deceleration by wildly misadjusting my carburetor. There are also some emission
control devices that are designed to prevent the occurrences I caused myself so
your true problem could lie there, too. You might also make sure your EGR valve
isn't stuck but such situations are generally accompanied by a rough (sometimes
exceedingly) idle.
You might also ask your computer for any codes (if you've got one).
-chris
colorado, usa
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