Having played with mostly fuel injection, I've got a quick question about a problem with my new ride.

I'm running an Edelbrock 4-barrel 600 CFM carb (pretty sure it's the 1406) on top of my 350, along with an inline electric fuel pump. Both are brand new (less than 500 miles). I bought the car like this.

No problems at first then this happened last night. Sounds like a fuel pump problem to me but not having much experience with carbs I figured I'd ask.

When driving it'll start to stumble and bog down badly, then catch it's breath for a second and run fine then stumble badly again. It'll do this for about 30 seconds then just bog down and refuse to recover until I come to a stop at which point it'll just die. If I keep driving it won't go over 10mph and it'll just die eventually anyway.

I can sit there for 30 seconds, with the fuel pump priming, and it'll start right back up and run for a champ for a few minutes and do the same thing again.

Sounds to me like the brand new fuel pump was bad out of the box but wasn't sure if it was a carb issue possibly?

 

Just to be sure , you should rent a fuel pressure gauge . Now , between the inline fuel pump and the carburetor , you must have a fuel pressure regulator . Check the fuel pressure , when priming , before the regulator and after the regulator . Pressure should be higher on the fuel pump side has you've guessed . On the carb side pressure should be between 1 and 5 psi max .

 

What pump are you using, and what do you have for a pickup in the tank?

 

The pump is a holley IIRC (not at home right now), I'm unsure of model number but it's brand new and probably one of the cheaper ones.

I don't know what the previous owner used as a pickup.

I'll double check on the pump model when I get home.

 

sounds like vapor lock could be the culprit too. How hot are the fuel lines getting? routed near any heat sources?

 

They're near the passenger's side header and the headers are uncoated so that's possible, I'll try moving them away from that source of heat.

Edit: Now that I'm home and looking at them it appears they're decently far away to rule that out.

 

well then grab a fuel pressure guage and duct tape it to the windshield to see what happens when it acts up. Or when it starts to buck shut it off and see if the bowls are empty.