Sunpro Fuel level gauge

[Jason280zx]

Hey guys! So I need some help figuring out how to make my sunpro fuel level gauge to work properly on my 1983 280zx, now I do know they work by resistances to get accurate results, but im not familiar what exactly is the resistances are, and I want the gauge to read close enough to feel comfortable driving around knowing how much fuel I have left. I do understand that its a universal unit and not all gas tanks are the same size so work with me here. So I got the basic wiring down, and for ya'll who are familiar with the sunpro gauge, it has 3 points of connections, 1st is for the 12V source, 2nd is the ground, and 3rd is the sender. Now ive got the first 2, but which wire exactly do I connect the sender to the gas tank. The gas tank cover has a connection, and on that connection are 4 wires coming out from the gas tank. 1 is black (im assuming that's ground), another is red (im assuming that's the 12V source), Now the other two, identified in the wiring diagrams, one is a yellow wire, and the other is Yellow with black tread. Now Im not sure which wire of the two is for the "Sub gauge float" and "Main gauge float", but at the moment I have the gauge connected to the yellow wire and my fuel level reads around 1/2 or 3/4 of tank, but really I have about 1/4 of a tank from estimating putting in about 5 Gallons. When I connect the yellow with black tread, it reads very close to full. So my questions are "What wire do I link the gauge unit to? Or do I put both wires together then do the resistances?" Let me know if im missing any information that I you think I should know. I have looked around and search but im not getting what im looking for, I seen other post about other gauge units beside mine also recalling about resistances and stuff, Im hoping if anyone here uses and is familiar with the sunpro fuel level gauge in the same car and can really help me.

Edited August 24, 2013 by Jason280zx