so my friend was switching my old fuel pump with the fuel pump from my parts car...now my gas gauge wont work, what could he have possibly F-ed up in this process? could the bobber have been fux0r3d with? any help would be great...thanx...arjay

 

the wire probably came loose or something.

 

There are four wires going to the fuel tank: fuel pump power, fuel level sender, low fuel warning light and a ground for all three. Check them.