I've had an ongoing fuel starvation issue where the car will get ahead of the fuel pump, and drain the float bowls till the car leans out, then dies out completely - let of the gas a section and it refills the bowls enough to keep going. It used to just be when I matted the pedal for an extended period, but its gotten worse, to the point where the car can't climb hills at reasonable speed. So today I replaced the mechanical fuel pump with a new one. Not a terrible job, the push rod is a tad annoying, but not impossible. Started up, checked for leaks, went for a drive. Identical problem. No differenece what so ever. There is no fuel filter between the gas tank and the pump, and no filter - for the moment - between the pump and carb. Float height just recently set to spec, it wasn't out more than a 1/16th prior.

So, possible problems - something lodged in the carbs inlet system, or a bad fuel pump lobe on the cam. Cam and the motor only have 20k miles, so I doubt this to be the case. I guess I'll go deeper into the carb - but does anybody else have any further throughts?

 

Kinked line between the pump and carb.

Or a small hole in one of the short sections of rubber line by the tank or the pump (sucks air in and plays havoc with the fuel pump, but may not cause a visible external leak).

Blockage in the fuel line.

The pickup "sock" in the tank is clogged up and collapsed. Fuel tank not vented properly allowing a vacuum to be generated inside the tank as the fuel level goes down (simple as loosening the gas cap to check for this problem).

That's what comes immediately to mind.

 

Good thoughts. I do have a fairly crappy looking section of hose from the fuel line coming from the tank up to the fuel pump. It doesn't leak at all, but like you said, maybe its finding air. Easy enough to change...

 

Here is an update. I replaced the short section of rubber hose from the fuel line coming from the tank to the fuel pump. No change. I'm running an aggressively high level of fuel in the carb to try and combat this starvation issue, but it still doesn't help. Loosening the gas cap had no effect. I'm not convinced that there could be a blockage or restriction somewhere from the tank to the fuel pump - when I remove the hose up front everything is under pressure, it pushed fuel out w/ pretty decent force - the tank is always under pressure when I remove the cap.

Any other thoughts.

 

How does it do with the gas cap off?

 

Not a lick of difference. Tank usually seems to be under pressure at rest, every time I've worked on this fuel system fuel starts coming right out the main line from the tank, and will continue to until its plugged.

I'm going to get a decent length of 3/8th's hose and run a fuel tank from the passengers seat up the road a tad to see how things work out - if that lets it run fine, I'll know I've got more issues behind the pump, and possibly in the tank. The problem has progressed rapidly in the last 3-4 days from occasional trouble to full out inability to drive at more than a fast idle. Perhaps it is the strainer and it has collapsed.

 

Try a different carb all together. Throw a holly on it and see if it doesnt run prefect.

 

Its not the carb - this fuel starvation problem has existed since I bought this car almost 2 years ago, and has progessively gotten worse while I had the CC-Qjet, and now the Edelbrock. Throwing a Holley on there wouldn't do a thing if it doesn't have fuel pressure.

 

Could be. Try blowing out the line with compressed air.

 

That's a great idea. I've got a week off next week, I hope to resolve this, and hopefully have this thing up and running.

 

Worked perfectly - fuel starvation is now completely absent. Didn't sound like it was bubble up through the fuel, I had about 1/3 tank, but maybe through a bypass valve. Either way, it did the job, great call.

 

Hey there, how is your car running now? I am having a similar problem with my car, I slam down the pedal to the floor, car goes great for about 100 feet then it begins to want to die out. Like it's being strangled. I let off the gas and then press the pedal a bit and the car just rolls like nothing is wrong.