Back to the fuel gauge

I think I understand where you are going. However, I now have 6 gallons in the tank, so it is not empty. When I installed the sending unit, the wiper was in its resting position, fully extended, and it (should have) shown empty. When I reinstalled the tank it was empty, and the float and arm were at the bottom of their travel as checked visually (I should have powered up the gauge to confirm). Now, with 6 gallons added, it only registers 1/8.