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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: magnum440d100]
#1210699
04/07/12 10:02 AM
04/07/12 10:02 AM
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Joined: Jan 2003
Posts: 5,894
Florida
Locomotion
master
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master
Joined: Jan 2003
Posts: 5,894
Florida
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Since the 360 cam is likely bigger than the 318 cam, then the vacuum signal would be a little weaker. That could explain why the existing "flat spot" got worse. Unless someone suggested it and I missed it, is there any way to get an accellerator pump squirter with bigger nozzles, or finding another one to drill out with wire drills? Change in small increments, like .003" - .005".
Changing the pump arm position changes the total volume of fuel delivered throughout the travel. (longer or shorter squirt) The pump squirter nozzles determine the "rate" of delivery. i.e.: bigger squirters will squirt more, but for a shorter time.
Carb may even need to be jetted a size or two bigger, which could help the "flat spot". But that shouldn't be used to actually cure the "flat spot" because then you'll be too rich the rest of the time.
Last edited by Locomotion; 04/07/12 10:12 AM.
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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: Secret Chimp]
#1210701
04/07/12 10:42 AM
04/07/12 10:42 AM
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Joined: Jan 2003
Posts: 27,728
places
79powerwagon
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,728
places
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Quote:
Throw that BBD or whatever out the window and have fun :P
The wisest statement of them all in this whole thread!  
To me, this sounds like a tuning/mechanical issue, not immediately a carb issue (as is the case in 98% of these kinds of posts). Throwing parts and money at the symptoms does not correct the problem. Proper understanding and diagnosis does. 
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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: 79powerwagon]
#1210702
04/07/12 02:02 PM
04/07/12 02:02 PM
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Joined: Jul 2011
Posts: 817
Eugene, Oregon
Secret Chimp
super stock
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super stock
Joined: Jul 2011
Posts: 817
Eugene, Oregon
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Quote:
Quote:
Throw that BBD or whatever out the window and have fun :P
The wisest statement of them all in this whole thread!
To me, this sounds like a tuning/mechanical issue, not immediately a carb issue (as is the case in 98% of these kinds of posts). Throwing parts and money at the symptoms does not correct the problem. Proper understanding and diagnosis does.
Awhile after I first came here I had to learn that any question was going to get a lot of weird irrelevant mechanical questions half the time.
"My car is really hard to start in the morning"
"What converter are you running?"
1967 Dodge Coronet Deluxe station wagon
1.03" T-bars, QA1 arms/rods, Cordoba/GM Metric/Volare brake & knuckle, XHDs, Hellwig rear sway, 318 Magnum w/ air gap, 727, 3.23s
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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: Secret Chimp]
#1210703
04/07/12 11:19 PM
04/07/12 11:19 PM
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Joined: Mar 2005
Posts: 862
Iowa State fan
kilroy
super stock
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super stock
Joined: Mar 2005
Posts: 862
Iowa State fan
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This is a free fix if it works so try it first.
If it is low speed just off idle hesitation/lean spot, that is created when you hold the throttle at a slight postition with out actuating the accelerator pump (like when you are pulling out of the driveway easily).
If this is the problem, try richening the idle mixture screws half a turn each. If it gets better, do an additional eighth of turn each until it goes away.
The explanation of this is the main wells are not active yet because of lack of engine speed, and the accelerator pump isnt moving so it cannot supply fuel, the only thing left to fix would be the idle mixture screws or idle system.
Ive fixed a lot of hesitations this way, just try it and see if it works, you wont be out anything and it only takes minutes to see if it worked.
Last edited by kilroy; 04/07/12 11:20 PM.
1973 Charger, former SE, former auto
I'm not trying to be difficult, it comes naturally....
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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: kilroy]
#1210704
04/11/12 07:00 PM
04/11/12 07:00 PM
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Joined: Jun 2011
Posts: 1,039
ALBERTA CANADA
CUDA8U
super stock
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super stock
Joined: Jun 2011
Posts: 1,039
ALBERTA CANADA
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Quote:
This is a free fix if it works so try it first.
If it is low speed just off idle hesitation/lean spot, that is created when you hold the throttle at a slight postition with out actuating the accelerator pump (like when you are pulling out of the driveway easily).
If this is the problem, try richening the idle mixture screws half a turn each. If it gets better, do an additional eighth of turn each until it goes away.
The explanation of this is the main wells are not active yet because of lack of engine speed, and the accelerator pump isnt moving so it cannot supply fuel, the only thing left to fix would be the idle mixture screws or idle system.
Ive fixed a lot of hesitations this way, just try it and see if it works, you wont be out anything and it only takes minutes to see if it worked.
the squirters were too small on my car,with the 2800 stall,4:11 gears it needed a huge dump of fuel,first i went to 32's from 29's,as soon as i rechecked my accel pump and installed the 35's the problem was gone.
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Re: I'm lost...hesitation issue...bad acc pump symptoms??
[Re: 79powerwagon]
#1210705
04/11/12 07:48 PM
04/11/12 07:48 PM
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Joined: Jan 2010
Posts: 1,944
woodcrest, CA
magnum440d100
OP
top fuel
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OP
top fuel
Joined: Jan 2010
Posts: 1,944
woodcrest, CA
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Quote:
Quote:
Throw that BBD or whatever out the window and have fun :P
The wisest statement of them all in this whole thread!
To me, this sounds like a tuning/mechanical issue, not immediately a carb issue (as is the case in 98% of these kinds of posts). Throwing parts and money at the symptoms does not correct the problem. Proper understanding and diagnosis does.
I'm actually waiting for another set of intake gaskets/thermostat gasket so I can put the 4bbl intake on. I'm done messing with this 2bbl. I borrowed a friends 2bbl (same EXACT carb) and she runs like a sewing machine. I am borrowing it for the time being until the gaskets come in 
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