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Old 12-25-2011, 09:48 PM   #1
IOWNATRUCK
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acceleration?

When I hit the pedal sometimes it accelerates smoothly with no issues, but other times when i hit the pedal, it will almost "pop" and sound like its about to die, and then start to accelerate, is this an issue i should be concerned about? what could be the cause? oh and another thing, probably only had like 2-4 gallons in that could lead to it?
Thanks.

Last edited by IOWNATRUCK; 12-25-2011 at 10:01 PM.
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Old 12-25-2011, 10:14 PM   #2
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Re: acceleration?

What motor are you running? Carb or TBI? Might help to diagnose.
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Old 12-25-2011, 10:19 PM   #3
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Re: acceleration?

New gm 350 crate with edelbrock carb, recently calibrated and less than 2k on carb and trans and engine. could this just be because of low gas, or bad gas or gunk at the bottom of the tank that it doesnt usually get to unless the gas is low, for that matter? i mean, sometimes it accelerates fast as all hell, and then on the occasion that little thing occurs, could it be that im just pushing to far on the pedal and it needs some time to catch up? maybe i should be a little softer with the pedal and edge into speed instead of slamming it to the floor ha?
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Old 12-25-2011, 10:21 PM   #4
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Re: acceleration?

And, it doesnt happen with the car in park or with the e brake on, when its not moving, the engine revs perfectly smooth, no kicks or pops, only when its moving.
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Old 12-25-2011, 11:02 PM   #5
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Re: acceleration?

does it happen when warmed up or judt cold?
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Old 12-25-2011, 11:07 PM   #6
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Re: acceleration?

warmed up as well.
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Old 12-25-2011, 11:12 PM   #7
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Re: acceleration?

Could it be set to rich in that you pour more gas in than it could handle so it spits some into the tailpipe which would cause the pop and then get a good air fuel mix so it can accelerate.
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Old 12-27-2011, 12:10 PM   #8
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Re: acceleration?

I don't know much about edelbrock carburetors but if it only happens when you "hit it" it sounds to me like the accelerator pump. On Holley carburetors when you punch the gas the venturi effect alone is not enough to meet the demand and the engine stumbles, the pump shot shoots a stream of gas into the carb until it can basically catch up. Google it and see if it sounds like your problem, just a thought hope it helps.

BTW to check it on Holley's you remove the air cleaner look down the throat of the carburetor with the engine off and pull back the throttle shaft, you should see a nice solid stream of gas shoot out into the carburetor.

Last edited by Dapper Dan; 12-27-2011 at 12:18 PM.
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Old 12-27-2011, 06:54 PM   #9
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Re: acceleration?

May be as simple as you letting to much air in then the engine can digest this is why vacuum secondary carbs are good for the street, they wont let in to much air. So don't just punch it to the full beans go half then slowly roll to full
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Old 12-27-2011, 07:27 PM   #10
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Re: acceleration?

my truck did the same thing with my edelbrock 750 i bumped down to a 600 and its fine now and very peppy throttle response. you could also be feeding it too much timing
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Old 12-27-2011, 09:45 PM   #11
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Re: acceleration?

Quote:
Originally Posted by Dapper Dan View Post
I don't know much about edelbrock carburetors but if it only happens when you "hit it" it sounds to me like the accelerator pump. On Holley carburetors when you punch the gas the venturi effect alone is not enough to meet the demand and the engine stumbles, the pump shot shoots a stream of gas into the carb until it can basically catch up. Google it and see if it sounds like your problem, just a thought hope it helps.

BTW to check it on Holley's you remove the air cleaner look down the throat of the carburetor with the engine off and pull back the throttle shaft, you should see a nice solid stream of gas shoot out into the carburetor.
Almost all of the edelbrock carbs have a few different holes on the accelerator pump linkage, If you have a good bit of vacuum at idle you can probably lean up that shot enough to fix your problem just by going up one hole on the linkage, I've seen that fix this scenario a few times and it's a free and easy fix if it works.
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Old 12-27-2011, 09:59 PM   #12
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Re: acceleration?

My truck would pop out of my carb (Edelbrock 1407 750 cfm) and I fixed the issue by advancing my timing a little bit.
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