Fuel gauge not working on my 751

[dae06]

I realize that most times this issue is due to a bad sending unit, but- I took the sending wire off of the gauge and the needle didn't move. Also, when the key is on and I tap hard on the gauge many times, it does eventually move to where it shows fuel in the tank and when I turn the key off, within a tap or two it returns back to empty. So this makes me think it is actually the fuel gauge. Any thoughts?

 

[bobbie-g]

Sounds like it's a mechanical problem with the meter, doesn't it? I think Tazza once said if you remove the two wires from the sending unit, there was some trick about grounding one wire and the gauge should go to zero, then connecting that wire to 12v and the gauge would go to "full", which would indicate the meter was OK. I sure wouldn't try that without someone saying exactly how to do it, though. --- Here's an idea: Those analog meters have a permanent magnet behind the faceplate, which sort of wraps around the bottom of the meter. The gauge needle is attached to a very delicate moving coil of wire. The more current in the wire, the greater the magnetic field that it generates. That generated field interacts with the permanent magnet, moving the coil of wire and thus the needle. Once in a great while, a tiny sliver of metal can get pulled inside the mechanism near the coil, and stick to the permanent magnet. When that errant metal whisker touches the moving coil, it can cause the coil to stick. I've had pretty good success with dismantling the meter and using a pair of stainless tweezers to get the metal sliver(s) out. This is of course assuming that you can get the meter guts out of the housing. ---Bobbie-G

 

[Tazza]

Sounds like it's a mechanical problem with the meter, doesn't it? I think Tazza once said if you remove the two wires from the sending unit, there was some trick about grounding one wire and the gauge should go to zero, then connecting that wire to 12v and the gauge would go to "full", which would indicate the meter was OK. I sure wouldn't try that without someone saying exactly how to do it, though. --- Here's an idea: Those analog meters have a permanent magnet behind the faceplate, which sort of wraps around the bottom of the meter. The gauge needle is attached to a very delicate moving coil of wire. The more current in the wire, the greater the magnetic field that it generates. That generated field interacts with the permanent magnet, moving the coil of wire and thus the needle. Once in a great while, a tiny sliver of metal can get pulled inside the mechanism near the coil, and stick to the permanent magnet. When that errant metal whisker touches the moving coil, it can cause the coil to stick. I've had pretty good success with dismantling the meter and using a pair of stainless tweezers to get the metal sliver(s) out. This is of course assuming that you can get the meter guts out of the housing. ---Bobbie-G

Don't put power into the sender S connection, grounding it is ok, it should read a full tank, putting power into it will kill the gauge. New gauges have a note that says never put power into the sender connection or damage will occur.
For the price, talk to the dealer and get a new gauge, the last ones i got were under $30 from the dealer, they will be more than that now i'm sure.
Yours sounds like it is sticking inside. The needle should fly around when you tap the S connection to ground, no hesitation at all.
Bobbie-G mentions the exact same thing i have done in the past, opening the gauge up and freeing the internals. Sadly the ones i have tried to repair were too far gone, but i had a go anyway. You can't make it worse can you? you have nothing to loose, other than a bit of time if you had a go at a repair.