Fuel Gauge

[skeet85silverado]

My 85 truck fuel gauge is off. It moves all different postion accept the right one. Do i need to change the sending unit in the tank or is there something i can try before that, that could be causing this. Also when i called the auto store he asked if i had the sending unit with 3 fitting on top or two. Would i be able to tell this before dropping the tank? Thanks

[edge]

For what it's worth...
My 85 does samething, as well as oil psi ga.
I just put a plastic tank, and sender in from these people. http://www.mtscompany.com/chevy-gmc.htm
The sender has three hose stems coming out of top & once you drop your tank or use a mirror on a stick and worm your way into a position you can tell how many hose stems you have. 1 is main fuel pick-up and 1 for return from fuel pump the other is a vent line. Something like that anyway. I plugged my other two off and went with a vented cap. My fuel ga did same thing before and after new sender. (sender had no adjustment either)

The gauges reading funny I'm thinking is a bad ground to the gauges, connection or worn out gagues.

Let's see who answers...

[neverfinished]

I had a similar problem with my '73, the problem was/is the printed circuit that the gauges run on. My temp gauge and fuel gauge would go from working to not working to wildly incorrect. I pulled the gauge cluster and carefully cleaned any exposed wires then ran electrical tape across the exposed wires and put everything back in. The top layer of plastic that is laminated over the wiring has separated from the rest of the printed circuit.

[xtreme80]

To see if you have two hoses or three, just slide under your truck on a creeper (or on your back for us poor folk who can't afford a creeper) and look above the gas tank. You'll see how many hoses come over the frame rail and into the metal lines.

[skeet85silverado]

thanks guys