72 Charger fuel gauge incorrect

[jboucher250]

Hi, I have recently completed my restoration of my 72 Charger and one of my various bugs I noticed on the first ride (to the gas station) was that the fuel gauge does not read correctly.

It is the original fuel gauge, with a new sending unit and tank. I have found that it took a lot of fuel for the gauge to register above E and now that the tank is full, the gauge only reads a little over half full.

I was reading online and found some tests to run, but am still unsure what the issue could be. I have found that when I grounded the wire that is supposed to go to the sending unit with the key on, the gauge does go all the way up to full...so it seems that the gauge is working correctly (maybe). I have also found that the sending unit with this fuel tank of fuel registers 9.7 ohms.

Any ideas? For reference, here is the sending unit i purchased: https://www.amazon.com/gp/product/B000C7TWE6/

 

[dadsbee]

Sounds like you have some minor resistance or corrosion in the wire/connections as amazingly enough, with a repro sender, you have 10 ohms when full...... which is exactly what you use when calibrating the gauge to show full so your gauge should be spot on the F mark. Clean wire ends, make sure the gauge is snugged in tight and getting good ground.

 

[jboucher250]

Thanks, I will see what I can reach on the back of the gauge tomorrow night and try to check for good connections. Anything else I can do on the gauge end? I should add that I had the gauge out of the car to put a decal over the face to restore the look - also hoping nothing got damaged that I didn't notice

 

[dadsbee]

You should have checked and calibrated it when you were done the decals... but hind sight is 20/20. They are adjustable to some degree, but doubtful you can do it in the dash.