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Old 05-18-2009, 07:38 PM   #1
1988TTOP
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Default carb ?

i have a 650 dp holley on my car if u rev it up slowly the runs great but if u just open it all the way up she falls on her face and then backfires though the carb a buddy told me the power valve is shot is this right
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1988 Gt TTOPS 1 1/2 IN LOWERING SPRINGS KYB ADJ SHOCKS MSD COIL FRPP WIRES LONG TUBES O/R X PIPE FLOWMASTERS KING CORBA CLUTCH MGW SHORT THROW SHIFTER F CAM CRAN VALVE SPRINGS ROLLER ROCKERS 650 DP HOLLEY UPPER & LOWER CONTROL ARMS 4.10 GEARS
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Old 05-18-2009, 08:38 PM   #2
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Could be but check the accel pumps first.
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Old 05-18-2009, 08:53 PM   #3
1988TTOP
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how do you check the accelerator pump
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1988 Gt TTOPS 1 1/2 IN LOWERING SPRINGS KYB ADJ SHOCKS MSD COIL FRPP WIRES LONG TUBES O/R X PIPE FLOWMASTERS KING CORBA CLUTCH MGW SHORT THROW SHIFTER F CAM CRAN VALVE SPRINGS ROLLER ROCKERS 650 DP HOLLEY UPPER & LOWER CONTROL ARMS 4.10 GEARS
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Old 05-18-2009, 08:54 PM   #4
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it backfires out of the front 2 barrels
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1988 Gt TTOPS 1 1/2 IN LOWERING SPRINGS KYB ADJ SHOCKS MSD COIL FRPP WIRES LONG TUBES O/R X PIPE FLOWMASTERS KING CORBA CLUTCH MGW SHORT THROW SHIFTER F CAM CRAN VALVE SPRINGS ROLLER ROCKERS 650 DP HOLLEY UPPER & LOWER CONTROL ARMS 4.10 GEARS
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Old 05-19-2009, 12:29 AM   #5
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Not to sound like a dick, but why are you running a carburetor if you have no idea how they operate? You need to seriously go out and get a carburetor book from Barns n Noble and understand how a Holley works. A carbureted car will never run right unless you tune the carb to do so. And you can destroy an engine if you're badly tuned.

As far as your problem, the accelerator pump delivers fuel as you open the throttle, it's operated by a plastic cam screwed onto the throttle linkage. Make sure it's all working properly and try a bigger cam. If the pump shot is too lean then you can get carb backfires when you hit the throttle.
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Old 05-19-2009, 07:32 AM   #6
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+1 ^^^^^^^^


With the car OFF look down the barrels of the carb. Press the accelerator back and look for a small but strong stream of fuel coming from the squirters at the top of the venturies. Depending how your carb is set up the rears will follow quickly
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Old 05-19-2009, 07:37 AM   #7
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Quote:
Originally Posted by 1988TTOP View Post
how do you check the accelerator pump
Accelerator Pump Tuning video clip. LUK
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