whats usually the cause of the fuel guage not working, when the dual tanks do work still ? the needle never moves, its below E




and what tank is default - when the tank switching valve assembly is dead ?



thanks for anything

 

An open circuit (break in the wires) between the gauge & the senders will cause a pre-'87 fuel gauge to show E. Since it affects BOTH, it's more likely that it's between the gauge & the tank select switch, but it's still possible for BOTH senders to be bad on a 22-YO truck. I'd probably start by pulling the instrument cluster & polishing all the terminals with a red eraser or brown paper.

There's not a "default" tank on that style of fuel system. It will use gas from & return unused gas to whichever tank the selector valve is set to, and the valve stays wherever it is when it loses power.

Get a Haynes manual & read up on it. You don't have EFI, so you don't have the "dual-function reservoir" or any electric fuel pumps.

 

hmm ok thanks

well im going to try grounding out the sender wire for each tank while trying to get the guage to move, on either position,

if no luck then im going to remove the rear tank or whichever tank appears to be secondary, and the valve switching assembly and connect it directly to the fuel pump intake line

ive done it on chevies alot, the last one last fall on my 77 K-10 pickup, it is very easy to do on them,

but never have done it on a ford

so will be a new learning experience for me

if i dont get any guage needle movements

will never need to have two full tanks anyways

so no need to have both tanks anyways


might do this tomorrow,


thanks

 

Both times I've tried to save time by dropping ford tanks, we ended up spending more time messin' around with rust than if we woulda just pulled the bed in the first place.

Also could be as simple as the back of the gauges like Steve suggests.

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