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Old 07-28-2010, 12:10 AM
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question about my camaro and holley carb

i have a 1985 camaro z28 with a 350 in it. the motor is bored .30 over. comp valve train. machined 882 heads. weiand intake. and a holley 4777 650DB with mechanical secondaries.

my question and problem is this.

after driving the car for 5-10 minutes, it dies when i stop or go to slow down. my fuel pressure stays constant at 7.5 psi(i use holley blue fuel pump with braided line, holley regulator, moroso pressure gauge) i guy i know told me it dies because it does not have a dashpot, however this carb has never had a dashpot and when i called and asked jegs tech support they also said that no holley 4777 carb has a dashpot. does anyone know why i may be encountering this problem? also i have a borg warner t-5 manual transmision.

any and all replies are appreciated. thank you.

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Old 07-28-2010, 12:48 AM
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Engine at operating temp;

What is your idle RPM?

How much manifold vacuum at idle?

Initial ignition advance?

Where is your vacuum advance connected? ported or manifold??

Have you recently changed mechanical weights and/or springs in your distributor?

Are your float bowls adjusted to spec?

Post your cam specs. Always helpful.

Last edited by Overdriv; 07-28-2010 at 12:50 AM. Reason: adding question
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Old 07-28-2010, 09:09 AM
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Next time it does this let it die and then remove the air cleaner and look at the choke. Are the choke flaps open or closed?
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Old 07-28-2010, 09:15 AM
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Also, do you really need 7.5 psi on this engine? If all else fails, remove the fuel bowls, clean the needle and seats VERY thoroughly, and then lower the fuel pressure to 6 psi and see how it does.

P.S. try this after you take Overdrive's advice...
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Old 07-28-2010, 10:17 AM
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i am not sure of the specs on the cam i built the motor a few months ago and someone through the box away. i have not changed anything in the distributor, it is a msd streetfire. the idle on the car is 1200. the vauum advance on the carb is connected to a port on the carb. the gas in the front bowl barely comes out with the sight screw out and pump on. the back bowl is set just below the sight screw.
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Old 07-28-2010, 11:06 AM
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You mention it dies when you stop or slow down. Before the motor dies what is the motor doing. does it jerk, sputter, misfire, do you smell something?
We need details.
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Old 07-28-2010, 11:16 AM
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That idle speed needs to come down, 1200 ?, mine idles at 750.
Check the carb throttle blades, are the little slots on the fronts making a small square ?
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Old 07-28-2010, 11:42 AM
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it does not missfire or anything like that. no motor runs perfectly fine while driving down road it only dies when i stop or slow down depending on how fast i slow down.
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Old 07-28-2010, 12:07 PM
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Sound to me the primary float is set to low.
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