Technical Fuel pressure help.

I have a 53 Cadillac with a Chevy 350 and a Carter carb and the mechanical fuel pump wasn’t working so I bought a new one and it would work for a while and then not pump anymore so I decided to go electric. I bought an edelbrock micro fuel pump and it works fine with about 6 1/2 PSI for a while but then it drops to 0 PSI after running like 15 min or so. I blew out the lines from the pump to the carb and there’s no obstruction when I tried to blow into the tank it was hard but I’m guessing it’s because I had pumped like $30 of gas but I do hear bubbles when I blow into the tank with the air hose.
I’m stumped.


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Pull the tank and have it cleaned. I had the same issue on a Plymouth a few years ago. The fuel fills the line when the car sits for awhile and then after driving for a few and the suction pulls the junk in the tank back to the pick up tube

 

I was afraid of that, thank you


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I had an issue with my Suburban where I could drive just fine, and it ran perfect around town. But get up to freeway speeds and it coughed to a halt from lack of fuel. Put a new mechanical pump on, and same problem. I pulled the tank, and when I took the sending unit out, the pickup tube had no sock, and had a big piece of clear plastic stuck in the end.
How the plastic got in the tank is beyond me, but guessing it was stuffed in the filler neck at some point, and slid down into the tank. Bought a new sending unit/float assembly, as I figured I better while it was out. No more issues ever again!

 

blocked tank vent or tank cap has no vent or vent in cap blocked .leave the petrol cap loose and see will it stay running.drop and clean tank.check fuel filter

 

pull the line off the input to the pump, point it at a bucket, see how fast and for how long fuel comes out.

 

I think you mean out as in may just dribble out if in side

 

If fuel won't flow into the pump, then the pickup or line is clogged. I said what I meant.

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LOL. Guess he told you!

Ben

 

Agree with Squirrels suggestion. Could also be the tank vent, it’s either a vented cap or a separate vent line. A non vented cap on a tank that needs a vented one can cause that problem. Also check/ replace the fuel filter.
Edit: A little late, I missed your post nunattax.

 

Thanks guys I appreciate all the ideas, I’ll start doing each until I find the culprit


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I stand by my statement but your minions disagree

 

A grand prix that did the same thing.

Instead of pulling it apart I cheated, I waited until it was almost on empty, took off gas cap, took off fuel line directly to the gas tank, turned air compressor on (140 psi) with a non regulated air blower and blew thru the line.

Blew the sock off the end of the pick up, reinstalled the fuel hose with a filter before the fuel pump. Drive it another 3 yrs with no problem and sold it.