I think i have bad sending units in my 76, anyone have bouncing fuel guages??

[RyanD.]

I have a 1976 sierra with dual tanks, it has been sitting for 13 years, when both tanks are empty i turn the ignition on, the needle sweeps very quickly to way over full and holds there, when i turn it off it goes back down to half, on tank 2 when i turn the key on it bounces to half and stays there, the same problems happen no matter how much gas is in the tank, has anyone had this problem, i was thinking sending units, i have changed the guage in the dash (old one didnt work at all) to a used one from my parts truck, thanks for any help.

[pokethesmot]

i think i rember some one on this sight sayin something about cheking the ground to the gauge

[rfmaster]

Ryan
Fuel sending unit in our trucks operated over the following range: 0 ohms empty, 90 ohms full. As previous poster stated check electrical grounds between gas tank ground tab (located on the top of the sending unit) and frame of the truck. These are commonly overlooked, broken in haste, etc. Expect to replace gas tanks as moisture may have rotted gas tanks from inside.

//RF

Good luck