67 mustang carb popping help?
08-09-2009, 01:40 PM
#1
Thread Starter
Join Date: Aug 2009
Location: az
Posts: 3
67 mustang carb popping help?
1967 Mustang / V8-289 / Holloy -2 Barrell Carb
PROBLEM
Carb. Popping on acceleration/ Idles fine, and when accelerates in park or neutral it runs fine. When I take main fuel line off carb. After running air forces out then the gas comes.
This car sat for 15 years/ I recently started workimg on it
THINGS IV’E DONE
Professional rebuild of carb.
ALL NEW - fuel pump, fuel tank, sending unit, fuel filters, points, spark plugs, Vacume advance (unit located off the distributor)
Timing and points have been adjusted.
THANK YOU ANY ADVICE MUCH APPRECIATED!
PROBLEM
Carb. Popping on acceleration/ Idles fine, and when accelerates in park or neutral it runs fine. When I take main fuel line off carb. After running air forces out then the gas comes.
This car sat for 15 years/ I recently started workimg on it
THINGS IV’E DONE
Professional rebuild of carb.
ALL NEW - fuel pump, fuel tank, sending unit, fuel filters, points, spark plugs, Vacume advance (unit located off the distributor)
Timing and points have been adjusted.
THANK YOU ANY ADVICE MUCH APPRECIATED!
08-09-2009, 02:47 PM
#2
5th Gear Member
Join Date: Mar 2005
Location: Marquette Mi
Posts: 3,566
Sometimes a vacuum leak, such as a bad intake gasket, can cause that. I havent seen it on a Ford, but that is exactly how it acts. Only pops under load, is fine in neutral. Other causes of backfire through the carb are retarded timing, broken or bent push rods, collapsed lifter, bent valve, and lose or misadjusted rocker arms.
Timing usually will backfire any time the throttle is opened quickly. Collapsed lifters, bent push rods and rocker problems will usually also cause a constant backfire/popping at idle and revving in neutral.
Best guess is vacuum leak somewhere or an ignition problem. Hard to tell over the net.
Timing usually will backfire any time the throttle is opened quickly. Collapsed lifters, bent push rods and rocker problems will usually also cause a constant backfire/popping at idle and revving in neutral.
Best guess is vacuum leak somewhere or an ignition problem. Hard to tell over the net.
08-10-2009, 05:51 AM
#3
6th Gear Member
Join Date: Oct 2006
Location: Cork, Ireland
Posts: 6,417
probably both. check again on your timing with timing gun, make sure to check of your balancer marking is fine (so that TDC actually matches engine TDC).
when idling spray WD40 or similar around the intake gaskets at carb base etc. Any change in idle indicates vacuum leak there. (don't spray into the carb while running as this will definetly change idle)
when idling spray WD40 or similar around the intake gaskets at carb base etc. Any change in idle indicates vacuum leak there. (don't spray into the carb while running as this will definetly change idle)
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