Pulling my hair out for a friend here!! Little background. Fuel gauge hasnt worked on this car for years. Owner replaced the fuel tank fuel sender had the resister checked which Im told is good. Sender wire disconnected and grounded to gas tank strap gauge goes to full Key on sender wire disconnected and attached to a test light it flashes intermittantly which Im told is normal in both respects.

Now heres the kicker......if I remove the sender and attach the wire and ground the sender it functions by hand down empty up full. As soon as I submerge the float/sender in the tank it ceases to function I've looked in the filler whole and operated the float with a long screwdriver thru the filler hole and it has plenty of clearance and doesnt bind Tried numerous ground locations but no luck. I checked the cluster and the gauge cluster has a good ground as well. Im at wits end with this :-(

Don't waste any more time on the dash, the problem is with the sender & while you've tried the right tests something is being missed...

Is it grounded correctly? Does it have this strap?

http://www.ebay.com/sch/i.html?_trksid=p...0&_from=R40

Yuppers The original ground strap was missing so I used a wire with two alligator clips to several spots fuel line (like factory) clean surface on body and gas tank strap All of the grounds are suitable as long as the sender is out of the tank as soon as the sender is in the tank it ceases to function Also checked with a circuit tester tank installed and sender installed the sender has a good ground at the round base that locks into the tank

have you tried in a bucket of gas?

Tried it in a bucket of water and wired to the car the gauge still doesnt work But I do get varying resistance with an ohm meter hooked to it on the workbench

When you pull it out of the tank where are you attaching the ground?

Same as when its installed in the tank to (doublecheck my connections) Jumper wire from frame of sender to the body or fuel line to fuel line

If I connect the ground wire to either the gas tank strap or the fuel line at the body and ground the gauge wire the gauge goes to full I figured this ruled out the gauge wiring and resister?

well water is conductive, so might cause a problem, but either way.

as soon as you dunk it, the gauge stops reading?

out of a liquid, you can swing the arm slowly and watch the gauge move?

or have you tried that at all?

also can you hold it at a level then dunk it and see if it goes away?

Yes out of the tank and wired up the gauge works properly by hand I even went as far as to cut the float off the previous sender Nylon tie it in the full position and hook it up and it reads full (did this to verify any obstructions in the tank. Installed that sender in the tank and no reading If I remove it while the tanks in the car it goes to full when I turn the key back on! I never actually tried to install it with the key on and connected

dip it in the bucket again, key on with the float up.

Regardless, I would probably replace it.

or if you can pull one out of a working car and see if it does the same thing.

but I am still guessing something is messed up in it.

just can't figure what.

gas isn't conductive, so it should not short out and ground.

I dunno but if the sender was shorting out one would think the gauge would go to full! As the reostat in the sender is nothing more then a controlled short.

I guess it depends on if it goes to infinte resistance or none.

the other choice is it could be causing an open in the circuit.

The sweeper arm is not making a tight connection with the windings, when its in liquid the arm is pulling away. I'd replace it with a new one. Or at Least get one from autozone to test.

Maybe this will confuse the issue but I got good resistance readings on an ohm meter but it still wouldn't move the gauge. New sender gave same readings and would move the gauge.