Holley Cold Start - Run Issues.

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idrift

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Been fighting this one for a few months now and with spring on the way,
it would be nice to get figured out.

It's a Holley street avenger 690 CFM. It has to be specific to this carb
because the 3310 that was on the car never had the same issues.

Starts right up cold or hot. Choke's set right. Floats set right.

After a cold start, it will for about 5 minutes then want to die like
it's getting no fuel, I have to pump the hell out of it and keep it revved
at 2k to keep it running. Even then sometimes I have to feather the
pedal to keep it running. I've tried changing the choke settings but it
doesn't make a difference at all. I figure it must be something with the
carb starting to get warm or the differential between the engine and
carb. It's on a edelbrock performer RPM manifold. Like I mentioned the
other holley which was a 3310 had zero problems, and it runs awesome
once it's all nice an warm....
 
big cam? wrong power valve maybe. Possibly leaning out when chokes off cause no fuel from power valve. When you feather it pump shot corrects it. just a thought.
 
Make sure the idle mixture screws are out far enough, might need adj., also check for vacuum leaks.
 
Sounds like it's going lean as soon as the choke comes off. Try adjusting the choke a notch or 2 richer and see what happens. You may also have the idle mixture set on the ragged edge of lean so you may have to tweak them out a 1/8~1/4 turn.
 
Snake said:
Any chance your intake has no cross over in it? could the carb be iceing up?
Click to expand...

The intake is a edelbrock performer air gap, so I wouldn't doubt it,
but it will still do it in the summer months.
 
daredevil said:
big cam? wrong power valve maybe. Possibly leaning out when chokes off cause no fuel from power valve. When you feather it pump shot corrects it. just a thought.
Click to expand...

Good thought, I'll look at the power valve against vacuum when she's
sputtering.
 
fishy68 said:
Sounds like it's going lean as soon as the choke comes off. Try adjusting the choke a notch or 2 richer and see what happens. You may also have the idle mixture set on the ragged edge of lean so you may have to tweak them out a 1/8~1/4 turn.
Click to expand...


I did play with the choke but the same thing happens even pulling off
later but I haven't pulled the screws out too much. Maybe I'll give them
a half turn and see if that helps. The darn thing is the 750 I had on it
was perfect cold or hot, that's why I think it's this carb. Both had
electric chockes etc. I have hear the street avenger carbs tend to
run really lean so I tweaked jets until they were good but the cold
idle problem is stumping me. Is there a difference in how they handle
air in the idle circuit?
 
idrift said:
Is there a difference in how they handle
air in the idle circuit?
Click to expand...

Yes, the avenger is metered leaner, so you may have to have the mixture screws out more for a steady idle, honestly thats what it sounds like, if there not out far enough it won't idle for crap, contrair to what people think, i called holley on my 650dp & wondered why the mixture screws had to be out 3.1/4 turns on this carb, He told me anywere from 1/2 too 3.1/2 is normal, as long as it stalls out when you bring 1 in your fine, What you should do at this point is, bring the idle screws out 1 full turn each before firing it up, see what happens, there is no reason the engine shouldn't run steady once warm with the choke "fully" open, keep us posted.

My 4777-7 650dp wouldn't even idle with mix screws 2 turns out from fully seated, & its a perf. carb, the nice thing i like about the newer DPs is they leaned out the idle curcuits a bit then the older ones, makes them alot easier on the eyes, The IABs (idle air bleeds) on the 4777-7 air .086" up front compaired to the older ones that were around .070". Throttle responce was outstanding & it could idle forever & never load up.
 
JoeDust451 said:
Yes, the avenger is metered leaner, so you may have to have the mixture screws out more for a steady idle, honestly thats what it sounds like, if there not out far enough it won't idle for crap, contrair to what people think, i called holley on my 650dp & wondered why the mixture screws had to be out 3.1/4 turns on this carb, He told me anywere from 1/2 too 3.1/2 is normal, as long as it stalls out when you bring 1 in your fine, What you should do at this point is, bring the idle screws out 1 full turn each before firing it up, see what happens, there is no reason the engine shouldn't run steady once warm with the choke "fully" open, keep us posted.

My 4777-7 650dp wouldn't even idle with mix screws 2 turns out from fully seated, & its a perf. carb, the nice thing i like about the newer DPs is they leaned out the idle curcuits a bit then the older ones, makes them alot easier on the eyes, The IABs (idle air bleeds) on the 4777-7 air .086" up front compaired to the older ones that were around .070". Throttle responce was outstanding & it could idle forever & never load up.
Click to expand...


Cool, thanks for the info, I'll give it a try.
 
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