Fuel Gauge not working

[vwnc]

Got a '67 bus with a fuel gauge that wasn't working. Took out the gas tank and cleaned in before reinstalling along with installing a new sending unit. Made sure the sending unit was properly grounded. Reinstalled motor and hooked up all the electrics accordingly. When I turn the ignition on, the fuel gauge makes a funny noise and the needle goes back and forth between empty and full and the stops for 20 seconds and then goes back to noise and the needle going back and forth. Thought about buying a good "aftermarket" one, but didn't want to rule out the possibility of fixing the existing one. Any thoughts?

[busdaddy]

Does it still do that if you disconnect the wire from the sender on the tank?
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[NUTSFORBUSES]

First-off, "A fuel gauge is supposed to work in a Split?"
Since 78 I've been struggling w this gauge.
Some guys build them Ok, and some don't-The idiom Grasping straws really.
Your issue is drawing power/resistance, then letting go>strange.

I have several gauges as many of us do including senders and I have soldered new chrome wires into senders before, but the sender is simple electronics, I would replace the gauge in your case< But then again, the "wiper" inside the sender could be corroded (common) at the top which would lose resistance as soon as the float reaches upward (no contact) That is why I say try to replace the gauge instead of bumper, valence, wires, gas, clutch, MOTOR. Under $75 diagnostic before you remove the motor & tank
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[chgrec]

I chased sender/gauge issues for a bit but finally got it fixed (I had 2 brand new, bad senders). Here is how I tested things.

Pull the sender wire from the tank sender unit and ground it, does it behave the same way or send the needle to Full?

Pull both wires from the gauge, ground one side & put 12v on the other side of the gauge, does it do the same thing or send the needle to Full?

If so, I'd replace the gauge as has been suggested....If it behaves normally then your sender unit or wiring may be compromised...
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[Culito]

If I remember right, the gauge has to be reliably grounded to the dash, too.
Or maybe that's just for the light. Who knows. I fill up every 200 miles.
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'64 standard w/2.0L type 4
'62 bug

[telford dorr]

If the issue is the sender, see this link.
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[Clara]