Holley Street Avenger Troubles
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Car: 1983 Camaro Z28
Engine: 350
Transmission: 700R4
Axle/Gears: 3.42
Holley Street Avenger Troubles
Alright, so I bought a Holley Street Avenger 670 rebuilt by National Carburetors for my new engine. I'm experiencing a hesitation off idle. It wasn't there for the first couple hundred miles then it gradually started getting worse.
It starts with a flick of the key, but if I try to rev it cold it dies. I have to gradually get it above 2500 or so then I can punch it. In drive if you punch it, it hesitates, then takes off like a bat out of hell. No problems accelerating once you get past the hesitation, and no problems cruising.
It does get slightly better when warmed up, but it's stil lthere.
I've been tweaking the carb over the last few hundred miles to no avail. Air/fuel mixture seems right on and warm idle speed is around 750 RPM.
At first I thought it was dumping too much fuel from the accelerator pump, but then I found if you half choke the carb the hesitation goes away.
What can I do to correct this problem? Accelerator pump is working correctly, do I simply not have enough fuel dumping into it off idle? Would installing a larger accelerator pump diaphram help? Right now I'm at a loss, but stalling while pulling out into south florida traffic is NOT Fun.
Oh yeah, engine specs: 350 4 bolt main, mild (4.40 lift) cam, stock single hump 1.92 heads pocket ported/polished, double roller timing set, high volume/pressure oil pump, edelbrock performer intake, HEI distributor with a MSD coil, and shortys.
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It starts with a flick of the key, but if I try to rev it cold it dies. I have to gradually get it above 2500 or so then I can punch it. In drive if you punch it, it hesitates, then takes off like a bat out of hell. No problems accelerating once you get past the hesitation, and no problems cruising.
It does get slightly better when warmed up, but it's stil lthere.
I've been tweaking the carb over the last few hundred miles to no avail. Air/fuel mixture seems right on and warm idle speed is around 750 RPM.
At first I thought it was dumping too much fuel from the accelerator pump, but then I found if you half choke the carb the hesitation goes away.
What can I do to correct this problem? Accelerator pump is working correctly, do I simply not have enough fuel dumping into it off idle? Would installing a larger accelerator pump diaphram help? Right now I'm at a loss, but stalling while pulling out into south florida traffic is NOT Fun.
Oh yeah, engine specs: 350 4 bolt main, mild (4.40 lift) cam, stock single hump 1.92 heads pocket ported/polished, double roller timing set, high volume/pressure oil pump, edelbrock performer intake, HEI distributor with a MSD coil, and shortys.
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#2
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I'm experiencing a hesitation off idle. It wasn't there for the first couple hundred miles then it gradually started getting worse.
...
I have to gradually get it above 2500 or so then I can punch it. In drive if you punch it, it hesitates, then takes off like a bat out of hell.
...
I have to gradually get it above 2500 or so then I can punch it. In drive if you punch it, it hesitates, then takes off like a bat out of hell.
Since you say it didn't always do this, something changed. Either timing (most carb problems are caused by ignition), or a plugged carb passage.
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Car: 1983 Camaro Z28
Engine: 350
Transmission: 700R4
Axle/Gears: 3.42
Re: Holley Street Avenger Troubles
Thanks. I found that the float adjustment level was off, it helped but it's still not 100%. I'm going to follow the Holley Tuning Guide in the FAQ's to jet the carb properly and install the correct power valves.
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I should have included float level in my list of assumptions.
The Holley tuning sticky is a great way to get a Holley running correctly.
The Holley tuning sticky is a great way to get a Holley running correctly.
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