Did you check to make sure the float arm was moving smoothly and that the contacts on the arm was making contact with the "resistance" board on the assembly?
When I did mine, I had to swap over the float arm, wires and the resistance board to the new fuel pump assembly since the one I got, the contact tabs were broke off. Tested the fuel gauge before I reinstalled into the tank and works perfectly.
Or
Did you get the wire harness too? The harness that goes from under the drivers side rear passenger seat, with a through grommet out to the fuel tank and speed sensors. I made my own from an 04 gas liberty and just spliced in 2 wires for the pump power and moved 2 wires for the fuel gauge. Good how-to in the tech section:
viewtopic.php?f=98&t=86136