is there a way to make the gauge reflect more than what's in the tank?

I was thinking along the line of adding potentiometers or bumping up the voltage with batteries on the circuitry behind the gauge itself. I don't have the wiring schematics and am not an electrical guru, thus appreciate any help. There's a 56 ohm resistor behind the gauge but bypassing that resistor merely increases the fuel gauge only by a little.

tks.