fuel sending unit

rewind your old one. The original had a triangular bobbin the wire was wrapped around to emulate the shape of the tank (fat bottom, narrow top in volume) so the sender had shorter wraps and wider apart where the float is highest because the float swing faster when there is less fuel volume changing level. the shorter wraps reflet smaller changes in the gauge. When the full footprint of the tank is now the fuel level (1/2 full?) after it gets under the spare well. then the change gets smaller and the wires get finer spaced. I belieive that's the case trying to visualize my old one that had the sense wire wrap rotted off and the wiper was jacked too.