fuel gauge wont work

[69projectKAOS]

i just had a new tank and sending unit put in on my 69 camaro by the body shop that did the paint. but the gauge isnt working. what should i check for?

[CarlC]

Does the gauge do anything at all? If so, what? How much fuel is in the tank?

[David Pozzi]

Make sure they connected the ground wire from tank to the floor near the
RH fuel strap. On the tank I think it just plugs into a tab on the ring, so it may have pulled off there.

[AintQik]

Like David said these things like grounds. If the gauge was working before I suppose we can rule that out. Power is supplied to the gauge, all the sending unit is is a variable resistor.

This is how I trouble shot mine, but I found my gauge to be bad.

First I removed the sender from the tank.
Then I ran a temp ground wire from the sender to a shared ground.
I checked the ground at the sender and gauge to make sure they were good.
I then moved the sender by hand to see if the Ohms changed. (read directly at the sender with a meter)
Then, I checked the back of the gauge where the input wire from the sender goes in to see if it read the same Ohms as the sender. It was not the same so I ran a temp wire from the sender to the gauge to make sure it was not the wire in the car. With the wire off the gauge the ohms were correct, with it on the gauge it was not leading me to believe I had a short within the gauge itself somehow. It turns out replacing the gauge fixed it.

If you are trying to be the least invasive and not remove anything make sure the ground is good and fwind the wire on the back of the gauge and read ohms. Then compare it to the wire out ot the sender. You can get to it in the trunk. Then go from there.

Or, take it back to the guy who installed it and tell him it doesn't work :)

[AintQik]

Wait, your car is painted? Did I miss the thread?

[69projectKAOS]

the gauge is just sitting below full on the line under F. and it doesn't move at all. the tank was full at one point but i actually ran out in my driveway because i noticed it wasn't working. maybe its the float?? because its a brand new tank and sending unit, and i was under the car yesterday and the black ground wire was mounted to the bottom of the trunk, is that in the right place??
^^^antiqik, yepp my baby is all painted and on the road. now its all about finishing up little things and dress up stuff .:6gears:]
here`s the link: https://www.pro-touring.com/forum/showthread.php?t=52989&highlight=69projectkaos

[CarlC]

Disconnect and ground the sending unit wire that goes to the gauge from plug in the trunk. It should move the gauge to E. If so, either what David said applies or there is a problem with the sending unit. The IGN key must be on for the test.