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Discussion Starter #1
Most of my experience with Holley's has been with double pumpers. I purchased a street avenger pt#0-80670 (670 e choke) new in late 06, put it on my car and it always had a dead spot. As soon as I would push the throttle it would act like it was going to die. Right off idle, cruising, stomping it, any time the accelerator pedal was pushed. then it would wake up and go.

I called Holley direct, they referred me to their specialist who deals with the Avenger line. I could never connect with him, did this about half a dozen times and gave up.

Finally the carb just popped and was dead, pulled it off my car, drained it, back in the box and on a shelf it went.

I've decided to try this carb again, I'm hoping somebody here knows where I should start first. It's been wrapped in plastic in the box and the box was shrink wrapped so I'm not sure if it needs to be rebuilt but it is still dead.
 

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Your original problem sounds like the accelerator pump not set up correctly. Maybe pull it apart and go through it, checking everything looks good and reassemble it. There are a number of adjustments you need to check before it goes back on the car. Best thing to do is look on the Holley web site there are good instructions on how the set up the carb and basic tuning when on the car. When its apart check what Power Valve (have a really close look at the diaphragm for damage) and jet sizes are. Power Valve should be around 65 and jetting maybe something like 68-70 on the Pri
Good luck.
 

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It's been wrapped in plastic in the box and the box was shrink wrapped so I'm not sure if it needs to be rebuilt but it is still dead.
'Popped' sounds like a power valve was blown. Change it.
Should have come with this kit installed, if not install one! http://www.holley.com/125-500.asp
Since you have let it set up for awhile, please do yourself a favor and buy the kit to rebuild it. The kit will include a power valve and instructions on fine tuning. purchase a genuine Holley kit - I get mine from Advanced Auto.

If you've never done one before, this will be a good exercise. Use a good clean table, buy a can of carb cleaner (gallon can) and a spray can or two of the same to clean it up real good. Varnish will leave deposits everywhere...must be clean! You can do it if you can change a carb.

Sorry if i've assumed too much, just trying to help!
 

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Depending on your cam specs duration numbers @ .050 will help determine power valve needed. Sounds like stated your pump shot and or squirters.
 

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I agree that the initial issue was likely related to accelerator pump tuning, based on your description.

I also agree that it would be a good idea to do a rebuild since it was totally dead the last time you used it, and that was 6 years ago.

The 6.5 PVs that come in many of the rebuild kits (and also stock in many/most Holleys) are just plain wrong if you have a mild street engine making the typical 12"+ of vacuum. You can usually downjet and get much better street manners if you match the PV to your specific setup. At the very least, you will need a vacuum gauge to dial this in properly.
 

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Discussion Starter #6 (Edited)
Funny thing is I was playing with the adjustment for the accelerator pump when it stopped working.

Also I thought these carbs weren't supposed to blow out their power valves?

Thanks for your help.
 

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Funny thing is I was playing with the adjustment for the accelerator pump when it stopped working.

Also I thought these carbs weren't supposed to blow out their power valves?

Thanks for your help.
The Avenger is supposed to come with the Power Valve blowout protection, but the valve is not an all-fail protection. If your carburetor is backfiring regularly, your power valve can blowout.

I think the suggestions in here are the best route. Start from square one and jet your carb with what came with it. Holley lists the basic settings and adjustment for each part list they have produced.

Also, a people often forget that a backfire (from carb) is always a lean conditon. You can have the jets too small? -lean condition. The jets are right, but you have a vacuum leak? -lean condition.

The acceleration problem you had could be mitigated with different acceleration cam lobe profile, if everything else is good to go on the carb.

So starting over with a fresh kit and seeting it with factory initial jetting and adjustments will definitely be a sound starting place.

GerryLP:cool:
 

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check vac with a vac gage, then put the correct pv in,what ever your vac is go with pv half of your vac reading,if, problem persist check ac pump or pump ajustment,ajustment should be barely touching ac pump arm,also check fuel pressure,sounds like a bogg,and check air fuel ajustment, do this by turning each screw one at a time,turn all the way in till engine starts to cut off then turn counter clockwise about one and a half to two turns or till you have your highest idle,do the other side the same way ,a vac gage would be a handy tool for this. good luck let us know what happens
 

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Had a similar issue with my 670 but it didn't quit just popping and big bog. B4 the weather changed I had it put on a dyno. Ended up increasing the squirter from a .031 to a .035, primaries from 65 to 70 and secondaries from 68 to 73. What a freaking difference. Engine is a GM crate 350 - 330hp with Hooker fenderwells, T350 and 4.11's in the rear and an hei for ignition.
 
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