Passenger tank gas gauge issues

[big_al273]

OK i have a 1988 V30 (K30 from 73-86) Crewcab with the TBI 454.

My issue is with the gas gauge readings from my passenger side tank (dual tanks), Both tanks are full and the in tank pumps both work as well as the switching valve. My issue is that when my passenger tank is selected my gauge does not seem to read properly (it reads 1/8-1/4 no matter what), my gauge is good and the drivers side tank shows correctly on the gauge when selected.

I know as fact the the switching valve changes the fuel feed from tank to tank properly as i recently dropped the drivers tank to install a new fuel line clamp some previous mechanic had forgotten and while this was ongoing i confirmed the fuel selector valve as switching to the proper tank correctly

If you need any more info to give me a better answer ask away, i have listed all i can think of that is relevant to my problem.

[hatzie]

The gauge works on the LH tank and both of the fuel pumps work and the truck runs on both LH & RH tanks...

Sender wire dead shorted to ground is E on the gauge.  There's not enough resistance in the RH gauge circuit.

One of two possibilities;
1 ) The sender wire between the RH tank and the valve is damaged and making partial contact with ground.
2 ) The RH sender is worn out.

[big_al273]

I will have to drop the passenger tank to fully inspect the wires too the sending unit, but there was no obvious damage to the wiring.
When the sending unit fails does it just immediately stop working? or does it go through a failure period?

thanks for the input.

[hatzie]

If had a regular cab you could pull the bed bolts and slide it back on 4x4 timbers.  I think it's under the cab on your rig.

The sender is a potentiometer.  It could get noisy like a volume control knob on your guitar, it could fail completely or, the resistance could drop off from the original 0-90Ohms to 0-whatever ohms...