Runs out of fuel with half a tank

[jagonza]

So my car , 77 with an ADF and Facet electric fuel pump, use to run all the way down to fumes, the low fuel light would go off.

No at about half a tank it "runs out of gas".

What I know:

There is about half a tank when this happens - measured it, not just trusting he gauge
Took out the fuel pickup , it seems to go all the way down to the bottom
The fuel lines are all new
I have a fuel filter betweeen the tank and the pump, and another near the carb- both are new and clear plastic ,they have fuel in them , no gunk
I have pressure at the carb until I don't.
The vacuum canister has been changed and I have tried it without the canister
Fuel pump is mounted as low as I can , which is about at the half tank level-hmmmmmm
I have tried opening the gas cap to release pressure, no impact.
The fuel pump is hooked up to the correct fitting on the tank
It seems to start when I take a turn, but does not fix itself after going straight
I carry a Gerry can with me and as soon as I refill the tank it works great ?


My guess is that the pump is sucking air when I make a turn and it can't reprime itself, any ideas on how to fix that ?

[vandor]

Pinhole in the fuel sender tube?

[jagonza]

Csaba, I will look at the sender tube for a hole


Any other ideas ?

[TStark]

Fought that for along time..couple different styles of cube pumps.

A facet can't pull more than a few inches new, and they loose it with a little age, i suspect.

I improved thing by bending hard line for all but the connections, to minimize loss of pulse, but it was not a solutionm.

put in a carter rotary, and made it a non-issue.

[carl]

usually if I have a problem of fuel stoppage it turns out to be a tank venting problem but you have already checked for that. I would start with a new or borrowed fuel sending unit/pickup assembly. I don't think any fuel pump would be able to determine what the fuel level is in the tank,, it's either sucking available fuel or for some reason has stopped doing it. In your situation you have a constant in that the fuel flow stops at mid tank and that's why I also suspect the pickup assembly.

[jagonza]

thank you for your response, i pulled the sender and looked at the pick up tube. i confirmed the pump is connected to the longer tube. there doesn't appear to be any holes etc in the tube. i blew a little air into it and it seems tight. none of the hoses look kinked- they were new about three months ago.

I wonder if my pump is dying and cant pull a head - it cant pump from a reservoir level lower than the bottom of the tank.

I will take drive this weekend with the gas cap off to confirm it is not a make up air issue .

oh one more thing - i have the clear filter in the engine area mounted horizontally and there is some fuel in there, put it id not full or even past the fittings.

[jagonza]

So i ran it with a full tank, took some high speed turns, up hills down hills, no issues at all. hmmmm

also took a look at the pickup tube in the tank and dont see anything - other than the filter sock is dissolved away.

I am leaning towards fuel pump issues. with the car running it showed 13+V at the pump, it doesnt make any noise , but you can feel it pumping if you put your hand on it.

I will check the screen in front to the pulp for build up.

does anyone know if the ADFA carb has a built in filter screen inside the body somewhere ??

[So Cal Mark]

there is an inlet screen in the carb but I doubt that is your issue

[spider2081]

Is your electric pump mounted in the spare tire area of the trunk or in the engine compartment? I think they work best when mounted close to the fuel tank.

[jagonza]

It is mounted in the truck, with a fuel filter between the tank and the pump.

[TStark]

https://www.summitracing.com/parts/crt-p4070/overview/

[vandor]

It is mounted in the truck, with a fuel filter between the tank and the pump.

The filter should be after the pump, as pumps are much better at pushing fuel than pulling it.