Gas gauge off

[dalekerr]

My new toy 67 model  started to run out of gas at 1/4 tank reading. When I filled it up it registered 1/4 over full.
Can the needle be removed and reset to cure this issue or does the gauge need replaced? The gauge is working, just off.

[Mike S]

 I don't think that gauge pointer can be physically moved on its shaft. The needle travel is determined by the sending unit's resistance at various fuel levels.
  Check the black sending unit ground connection wire that is secured to the chassis on the passenger side by the fuel gauge pipe to make sure it has an electrically clean ground. If that looks good then the sending unit is likely due to be replaced.

Mike

[dalekerr]

Thanks I plan to add vintage air in a week or so and will pull the speedometer assembly then and check all the grounds. If that is not the issue, could the sending unit float be adjusted to solve the problem?

[69Z28-RS]

The resistance range of the sending unit and gauge must be consistent; either the gauge or the sending unit might be the faulty culprit, and my guess would be the one that is 'reproduction'... or 'aftermarket' is the one at fault.

[firstgenaddict]

FWIW the GM sending units/pickups I have bought from the Chevrolet Parts dept have had no issues. I have bought a few repros which have had dead spots or inconsistent readings. The Chevrolet part was near double the price. 

[dalekerr]

Ok I removed the ground on the sending unit it made no difference wheather it was hooked up or not with the key on or off? I cleaned it up and reinstalled it. Gauge still shows over full?

[77thor]

Ok I removed the ground on the sending unit it made no difference wheather it was hooked up or not with the key on or off? I cleaned it up and reinstalled it. Gauge still shows over full?

You have an OPEN circuit... Obviously it's not the ground since it doesn't matter if it's hooked up or not.
So you have a break in the other wire.
Btw: the key needs to be ON to test the gauge.

[68Zproject]

Or the ground wire is broken between the sending unit.

[dalekerr]

Ok changed the leaking gas tank and put a new sending unit in,. I filled up and it still showed over full. I checked the gauge before adding gas and it was at empty. I pulled the dash today to change the lens, it was old and hard to see through. I thought I heard about a ground on the guage? Mine did not have any?

[67jeffreyt]

Can you force the gauge to empty by grounding the brown wire at the plug coupling in the trunk that goes to the sending unit?