'68 Barracuda -wire to fuel tank sender

all the time key in or not? Or only reads empty to 1/2 full? what have you replaced lately?
All the time. I bought the car knowing the fuel gauge didn't work and it read empty.I put gas in it and the gauge went to 1/2 and never moved since.Someone ran a wire from the sending unit were you plug in the gauge wire to the frame ,not sure why.i removed it .