Holley tuning help
#962250
03/30/11 12:57 AM
03/30/11 12:57 AM
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Joined: Jun 2007
Posts: 1,174 clarks summit pa
73cuda340
OP
super stock
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OP
super stock
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Posts: 1,174
clarks summit pa
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I have a 1985 w150 with a 318 that has a 650 double pumper, edelbrock air gap and headers with a full three inch exhaust, other than that it's stock. Im getting a very bad bog starting off and if I floor it the truck will stall. I have to feather the gas to get it moving and the it runs ok. I checked for accelerator pump shot and I get a shot as soon as I hit the throttle. The timing is at 14 inital and 34 total. I just swapped to the four barrel and am trying to get it sorted out. Any help appreciated.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Holley tuning help
[Re: ireland383]
#962252
03/30/11 07:58 AM
03/30/11 07:58 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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having to feather it, as in, pumping the gas when starting off? sounds like you need MORE pump shot.
I would start out by changing the size of the nozzle on the pump shot, one or 2 sizes bigger so that you get more fuel, faster. then you can start playing with the cams on the pump shot too if you need more duration of pump shot.
I had the same problem on a holley DP. I had to pump the gas 3 or 4 times to get the RPMs up without stalling it. went up a few sizes in nozzle, and also changed the cam so that I got a longer duration shot, and the problem went away
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Re: Holley tuning help
[Re: fox]
#962254
03/30/11 10:38 AM
03/30/11 10:38 AM
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Joined: Nov 2005
Posts: 1,943 San Angelo, Texas, U.S.A.
1968RR
top fuel
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top fuel
Joined: Nov 2005
Posts: 1,943
San Angelo, Texas, U.S.A.
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Off-idle bogs often mean that you're running rich. You need to make sure that 1. you're idle mixture screws are adjusted properly 2. you have correct power valves, and 3. your jetting is right. The first two things can be done with a vacuum gauge and a little patience. The third requires trial-and-error and a lot more patience.
"When I'm in a slump, I comfort myself by saying if I believe in dinosaurs, then somewhere, they must be believing in me. And if they believe in me, then I can believe in me." - Mookie Wilson
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Re: Holley tuning help
[Re: 70Cuda383]
#962257
03/30/11 01:16 PM
03/30/11 01:16 PM
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Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
I had the same problem on a holley DP. I had to pump the gas 3 or 4 times to get the RPMs up without stalling it. went up a few sizes in nozzle, and also changed the cam so that I got a longer duration shot, and the problem went away
Sounds like the carb had internal issues, maybe even vacuum leaks & you did a "bandade" fix, unless you had a high dur. cam & low manifold vacuum, there should be no reason an OOTB holley (properly sized) should need any more then Idle screw adj. & maybe a minor jet change, even with high dur. cams/low man. vacuum i can tune in a holley with minimal changes in squirters/cams IF the timing curve is set right.
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Re: Holley tuning help
[Re: 73cuda340]
#962260
03/31/11 07:32 PM
03/31/11 07:32 PM
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Joined: Jun 2007
Posts: 1,174 clarks summit pa
73cuda340
OP
super stock
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OP
super stock
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clarks summit pa
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Not sure on jet sizes or size of the squirters or the power valve. I haven't had this apart yet.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Holley tuning help
[Re: greenpigs]
#962263
04/01/11 02:01 PM
04/01/11 02:01 PM
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Joined: Jun 2007
Posts: 1,174 clarks summit pa
73cuda340
OP
super stock
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OP
super stock
Joined: Jun 2007
Posts: 1,174
clarks summit pa
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I adjusted the mixture screws and it is a little bit better now, but the bog is still there and now I have a little hesitation on the top end.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Holley tuning help
[Re: 73cuda340]
#962264
04/01/11 03:59 PM
04/01/11 03:59 PM
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Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
I adjusted the mixture screws and it is a little bit better now, but the bog is still there and now I have a little hesitation on the top end.
Go invest in a holley tuning book or 2, i own 3 of them, read em, then read em again. If you know the fuel system is good, the ignition/timing curve is good & no vacuum leaks, THEN look at the carb, most problems are blamed on the carb, because thats the 1st. thing you see when looking at your engine, but most problems are elsewhere.
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Re: Holley tuning help
[Re: 73cuda340]
#962265
04/01/11 07:51 PM
04/01/11 07:51 PM
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Joined: Jan 2003
Posts: 1,100 Fort Lauderdale
Dave440
super stock
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super stock
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Fort Lauderdale
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My First off....for a late model low compression engine with a stock cam in a heavy vehicle... a double pumper and air-gap intake is not the way to go. You want torque to get you off the line. That intake is rated 1500-6500 for a reason. You're hurting off the line torque and wasting fuel with an air gap. Plus ...double pumper carbs are meant to sit on top of a race engine with generally low vaccum signal and lumpy cams. Theyre jetted richer and also idle richer = wasted fuel. A regular Performer intake (NOT RPM or Air Gap RPM) and vacuum secondary carb is all you need for that setup and will provide more torque at lower rpm. If its a new intake and you can swap it for a performer....do it. Go with a 600 vac sec holley or Edelbrock 625/650 AVS carb and you'll be much happier. Of course.... theres always a Performer intake and Demonsizzler prepped Thermoquad! Small primaries = Gas mileage and Gobs of low rpm torque + Large vacuum secondaries for when your foot gets happy!
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Re: Holley tuning help
[Re: Dave440]
#962266
04/01/11 08:44 PM
04/01/11 08:44 PM
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Joined: Jun 2007
Posts: 1,174 clarks summit pa
73cuda340
OP
super stock
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super stock
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clarks summit pa
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I knew before hand that it wasnt the perfect combination for my setup. I only used this carb and intake setup because I already had them laying around as extra parts. Anything is better than the stock 2 barrel setup that was on it as that needed a complete rebuild. It was running so rich that your eyes would burn standing next to it and you could basically watch the gas gauge go down. The truck runs 100 times better than it did. The only problem is if I try to get on it quick it will bog down bad until I get moving. I just want to try to get this fine tuned for now until I get my 340 finished to put in it.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Holley tuning help
[Re: Dave440]
#962267
04/01/11 09:20 PM
04/01/11 09:20 PM
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Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
My Plus ...double pumper carbs are meant to sit on top of a race engine with generally low vaccum signal and lumpy cams. Theyre jetted richer and also idle richer = wasted fuel.
Not true.
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