1969 firebird fuel sending unit stuck on full?

[keith]

My 1969 firebird gas gauge says full, i was way down and filled it, didn't move at all. I took a hard U turn and the needle did move but stayed pegged after that at Full. I replaced the sending unit about 5 yrs ago when i bought a new tank. Is it bad? how do i test it when i drop the tank before i order a new one?

 

[Bodey]

Your sending unit will always read "full" if it has a bad ground. It will read empty if it has a bad power wire. Perhaps when you took that u'turn, the float got stuck. I would jumper a ground to the sending unit to see if it reads correctly. If it doesn't, you might need to replace the unit.

 

[melsg5]

As Bodey said, check for corrosion on the ground.