My car has been down for about a year and half with all the upgrades and stuff that I am doing to it. I installed a Racetronix fuel pump with kit in the car and now the fuel guage is not responding just going straight over past full with about 5 gallons of gas in it. I am assuming its a grounding problem so I thought I would ask and see if anyone knows where I should start. I did get the plug and play harness with the kit but it does the same thing either with the harness plugged in or just using the factory harness. Any help would be appreciated.

Thanks

 

Doesn't sound like a ground, but an open-not seeing the sending unit at all. Here is something I already had written up:

To help figure out what your fuel gauge problem is, locate the pump electrical connector on the rear of the floor pan under the car (by the fuel filter). It has purple, gray and black wires going to the fuel tank. Unplug the connector. With a meter, read resistance between the black and purple wires going to the tank.
approximate:
88 ohms = full
60 ohms = 3/4
43 ohms = 1/2
26 ohms = 1/4
1 ohm = empty
The readings should correspond to your gauge. If the reading(s) seem accurate to what you have in the tank, the sender is ok. If they don't, the sender or wiring has a problem.