After a long day at work last night, I fired up my '75 to release some stress and headed out to play. I drove around for about 30-40 mins playing and had no problems. I generally was just cruising but would occasionally go WOT from 60mph, 50mph, 40mph, 30mph and accelerate to 100 or so and then decelerate. Because I have had problems in the last couple months with my Vette dying at WOT from a dead start, I did not go WOT until the end of my cruise...

I found a nice, desolate, long stretch of road, came to a stop and went WOT. That's when it died. It accelerated hard for about 50-100' before it just flat died. It's now about midnight, I have the t-tops off, am still in my work clothes, and am beginning to feel a few sprinkles. I tried to start it repeatedly to no avail for the first 10-15 minutes. I figured the carb was flooded, so I became patient and waited 10-15 minutes between two last attempts to start it. I called my brother and he came out to help me. We were able to get it started by one of us holding the throttle plate closed while the other started it. But I am not convinced that really changed anything but the throttle plate was stuck wide open. Is my choke broken? It's an electronic choke on a Holley 670 Street Avenger, on a ZZ4 Crate Engine, that was tuned by Lars less than a year ago.

What do you suspect could be the problem? It runs fine when cruising and accelerating WOT while at 30mph+, but from a standstill, it just dies and then has a terrible time restarting.

Thanks for all help. I just can't figure this one out.

 

Fuel filter
Fuel pump
Float level

 

I wouldn't suspect this is the problem. The filters on my carb are internal. But it's worth a look.

What is the best way to check the pump?


I checked this and am ok.

Thank you.

 

Correct me if I'm wrong but if your car was warmed up shouldn't the throttle plates be open?

 

They stay open and seem to be stuck, even when cold starting.

 

That doesn't sound right. I have the same carb as you. Mine got stuck open once but after I took off the air cleaner and manually pushed them closed they worked fine ever since. Not sure why or how mine got stuck. I see you have an electronic choke. Do you have a multimeter to make sure it's getting power?

 

Yes, I do. I'll take a look at that when I get home and let y'all know.

 

Thats a good thought,
When you guys refer to the throttle plates, are you talking about the actual plates that open (primary and secondary) when you step on the accelerator? Or are you talking about the flap that opens when the choke is warm?

Also, just because the fuel level is at the point where it trickles out of the float bowl doesnt mean its set correctly.
I know thats Holleys specs but I have found that I needed mine to be a little higher than even with the bottom of the plug as it was starving at WOT

 

I'm talking about the flap that opens when the choke is warm.

I think my float levels are ok because Lars personally worked on and set mine less than a year ago at a "Tuning for Beer" tour. I have to think that something has failed or broken completely because my Vette ran beautifully after he tuned it. Also, keep in mind that I have driven my Vette less than 1000 miles since he tuned it, so it can't be that out of whack.

 

I was talking about the choke plate that opens as it warms up. I guess I assumed that's what the poster was talking about since he was asking if his choke was broken.

 

That's the same that I'm talking about. We're ok.

 

Check your pm (related to the carb and zz4) for an opinion question.

 

Sounds like fuel starvation to me. it could be a clogged fuel line or crud in the gas tank.(don't ask me how i know). been there done that with 3 different cars.. one was so bad had to remove the gas tank boil it out and blow out the gas line from the tank to the fuel pump to solve the problem.

 

Perhaps the reason its not running correctly is that it has sat for long periods.

Just because Lars tuned it wont make up for it sitting there for who knows how long
We all know that Lars does excellent work but maybe it got gummed up from sitting... I dont know.... Im actually just starting to understand carbs and I really like playing around with them... Look out Lars!... Just Kidding

 

if it sat for a long time it could be the gas went bad..

 

When I say it sat for a long time, I mean that I drove it at least once every 2 weeks.

 

How does this explain why it will not start after it bogs and dies?