I have a 1999 Chevy silverado 4x4 with a v8 in it?

[robotdreams]

I just put a new fuel pump in it. Before, the gas needle went back and forth wildly. Now that i put the pump in it just stays on empty. I think I wired it correctly. There are four wires; two black, one grey and one purple. Could it be the black ones or the other two that I need to switch?

[jac]

The gray is for the pump and the purple is for the fuel sender unit. The blacks are grounds. But you need to check the connections to see if they are burnt. GM on problems with burnt connections at the fuel pump around that year.

[bigltdl81]

you could have knocked the float loose if you did no matter how you hook up the wires it wont work