Fuel Gauge Problem

[CliffH]

I have a 1965 Corvair Monza Convertible. When the gas tank is full the fuel gauge reads only 1/4. What might be wrong and how do I fix it?

Thanks

CliffH

[Oldcar_Mechanic]

Sounds like you may have a bad sending unit in the tank.

Disconnect the wire to the sending unit and with the ignition key in the on position, ground the wire. If the gauge swings to the full mark, it's the sending unit.

Have someone watch the gauge when you do this so you don't ruin the gauge by pegging the needle.

Ron

[60ratrod]

if it is the sending unit it is typically caused by previous owners not filling it all the way up. what happens is the float on the unit will only rise as far as the owner would fill it to. this often happens on newer cars. but typically the intank fuel pump would fail cause it would get too hot from lack of fuel to properly cool it.

[saaburban]

check the float first. had old Dodge with same issue. Cleaned off "junk" from 70's gas and general debris from rod.