No fuel pressure after 20 mins driving

[wbedwards]

36 flathead is prob on the mark. I worked for a tractor dealer while in college. They had one that would do that after a short period of running and after it was turned of would start right up. They tried everything as you have, turns out, it was a shop rag in the diesel tank.

wbewards

[funrunr]

Originally Posted by George/Maine

I would move the filter to inlet at fuel block. Then blow back fuel line with 40 lbs. air. to tank.

Maybe add a fuel filter close to the fuel block but keep the one you have before the pump there.
As stated before above, sounds as if something in the tank. By any chance are there any lines close to a heat source such as exhaust, heater hose or radiator hose. My wife's 74 bronco had a radiator hose close to the fuel line going to carb. It had all the same symptoms and took me a bunch of trial and errors to figure out.
Good luck and keep us informed

[Mike51Merc]

Originally Posted by 19Fordy

Drain the liquid from those gauges and try again to see if you still get a zero reading.

I agree. Just a little temperature rise and you can actually watch those gauges drop to zero. Some have rubber plugs you can "burp" to let the pressure out.

[George/Maine]

If you added a filter to your pump some have them some not.
Put the filter up near fire wall clear would be nice. This is not fuel injection loose the return line. The pump should be near tank my 39 its behind the wheel in side frame.
Make sure line is clear no rubber hoses and nice thing about electric pump let it run for few minutes and see if it pumps a gallon. Put a larger gauge wire to pump clean frame ground.

[Kahuna]

I also think it may be a loss of voltage. Is the pump wired for power thru the coil resistor?

[ford38v8]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by George/Maine

...This is not fuel injection loose the return line....

No, but most of us don't live on the coast of Maine where most folks never heard of vapor lock.

[George/Maine]

I don't know what you do out west but up here we have never heard of return line for Electric fuel pump. They do sell tanks with return lines but that's for fuel injection engines. If you had something blocking line you would sit there pumping gas back to your tank. If that's what you do good luck .

[f1builder]

i don't know about fuel line being blocked, when that happens the gauge usually fluctuates quite a bit.

[ford38v8]

George, I hear ya and agree. No return line needed for an electric pump. The mechanical pump is a killer, however.

[Marv]

Some high pressure high volume electric pumps require a return line off of the pressure regulator. I have one on my car.

[Mike51Merc]

Originally Posted by Marv

Some high pressure high volume electric pumps require a return line off of the pressure regulator. I have one on my car.

Yeah, but nobody should have one of those for a flathead.

[sidevalve8ba]

Originally Posted by Mike51Merc

Yeah, but nobody should have one of those for a flathead.

I would have to agree. Too much pressure and too much volume.