HELP with 1954 Gas Gauge

[trucks72]

This is not the usual truck I deal with. I will tell you what I have done first. First, original wiring, original gauge, new sending unit. Gauge did not work. Second, original wiring,new gauge, same sending unit. Did not work. After this the man wanted new wiring so it would look better. Third, new wiring, new gauge, another new sending unit. Did not work. I checked to see if I was getting hot to gauge. I was. Checked to see if hot was going all the way to tank with the wire off the sending unit. It was. Checked to see if ground on sending unit was good. It was. I took the face plate off the gauge and moved the needle to full. Then turned the key on, the needle moved to empty. If I unplug the wire on the sending unit and take it off the needle will not move. It should move pass full right? I can not make this gauge work at all. What am I doing wrong? NEED HELP?