1940 ford fuel problem

[MODELAMECHANIC]

Hi everyone,

I am working on a 1940 Ford, the problem is the car runs great at idle and long straight roads. As soon as I hit a hill the car runs out of gas. The tank is 3/4 full and no electrical problems, 2 p.s.i. fuel pressure, Sunday I am going to blow out the fuel line and maybe lift the sending unit out to inspect the fuel line into the tank. Any help would be great

mike

[Dave@Moon]

Check the fuel pressure at idle and at extended higher rpms, just in case the fuel filter or pickup is blocked with crud. Watch for it to begin to decline for no reason after a while.

If it passes that test, check your carburetor bolts and carb-manifold gasket. If they're loose, or if for any other reason air is getting by under the carb, the engine will lean-out and die. A heavy air cleaner can tilt an carb pretty far going up hills or around bends if 1 or more bolts are loose.

[Jim_Edwards]

Hi everyone,

I am working on a 1940 Ford, the problem is the car runs great at idle and long straight roads. As soon as I hit a hill the car runs out of gas. The tank is 3/4 full and no electrical problems, 2 p.s.i. fuel pressure, Sunday I am going to blow out the fuel line and maybe lift the sending unit out to inspect the fuel line into the tank. Any help would be great

mike

I'd try a quart of wood alcohol in the tank before anything else. Sounds like water in the gas tank migrating to the pickup on hills to me.

[keiser31]

I had that same problem with a 1957 Chevy stepside pickup years ago. Every time I went up hill, the truck would die. Seems that there was a flake of rust in the fuel line that flipped up to block the line and stop the flow of fuel. Took me a long time to figure that one out.

[Dave@Moon]

I'd try a quart of wood alcohol in the tank before anything else. Sounds like water in the gas tank migrating to the pickup on hills to me.

That is a possibility if the pickup inside the tank is towards the rear of the car, which would be pretty unusual. Most cars die out going downhill when there's water in the tank, or in hard turns in 1 particular direction.

[MODELAMECHANIC]

update,
thanks for all your info, ran car at idle 2 p.s.i.pressure. reved up engine and fuel did begin to decline to almost a dribble, then returned to pulsing amount at idle.
any new thoughts?

thanks,
mike

[keiser31]

update,
thanks for all your info, ran car at idle 2 p.s.i.pressure. reved up engine and fuel did begin to decline to almost a dribble, then returned to pulsing amount at idle.
any new thoughts?

thanks,
mike

EXACTLY what my Chevy truck situation was. Sorry to repeat my theory, but deja vu.

[MODELAMECHANIC]

Keiser31,

thanks for the info Sunday afternoon i will pull the sending unit up and see how bad the tank is. then blow back from the electric fuel pump back to the tank

mike

[De Soto Frank]

Sounds like either air bleeding into the fuel line between the tank and the pump, or the line between the tank and pump is restricted (either kinked or packed with fine rust from the gas-tank). Or pehaps a rubber hose is collapsing under vacuum of the pump...

Your fuel starvation at speeds above idle suggest that the fuel supply cannot furnish enough volume...

Went through the fine-rust issue with both a '64 Valiant and a '60 Chrysler a few years ago.

[Jim_Edwards]

Keiser31,

thanks for the info Sunday afternoon i will pull the sending unit up and see how bad the tank is. then blow back from the electric fuel pump back to the tank

mike

Where in the scheme of things is the electric fuel pump located? If it is too far from the tank that could be the problem. Electric fuel pumps are designed to push fuel not pull it. With only two lbs of pressure if that fuel pump is more than a couple of feet from the fuel tank it might not even push enough fuel under the best of circumstances. If the pump is properly located and one of the adjustable types, I'd sure try boosting the pressure up a pound or two before dropping the tank. I've had electric fuel pumps that failed to deliver anywhere close to the fuel volume an engine requires above idle.

Jim

[MODELAMECHANIC]

Update on 40 Ford!!

Removed fuel line from back of electric fuel pump which is located 18 inches forward of the fuel tank. Blew out line, removed sending unit inspected fuel tank minor rust at the top of the tank no flakes. put everything back together road tested, car runs perfect.

thanks to all of you for your tech help

mike

[keiser31]

Thanks for the update. Always good to hear about getting a vehicle running well again and back on the road.