68 camaro Fuel gauge reads empty

[Badley]

I have factory console gauges and my fuel gauge reads empty even though I know it has over 5 gallons in it. I just replaced my old sending unit with one from ricks camaro. My old sending units resistor broke causing a constant full read. I checked the fuel guage with a gauge testor. The gauge functioned properly, testing from the sending unit connector.

So my question is what could cause the gauge to read empty?