88 Pickup DLX with SR-5 cluster:

I'd like to install an aftermarket fuel gauge because I have lost hope of ever fixing or replacing the factory unit.

How do I select a gauge? What resistance range am I looking for?

Any suggestions would be greatly appreciated

 

I have a 94 Toyota Truck and I just upgraded that system to an SR5. The 94 4runner FSM was a great source for me. BE-50 has the measurements for resistance and float position. BE-50 is pg 50 of the Body Electrical System. The SR5 fuel gauge has two parts. The fuel level which uses a float and varying resistance sending unit to the fuel gauge. The 2nd part is the dummy light which is what I upgraded too. There is a separate thermistor next to the float which is wired to an idiot light in the dash which illuminates when just about out of gas. The thermistor provides a different resistance when submerged in gas versus not. That is what I added to my truck. It required me to add a wire from the instrument gauge to a connector under the passenger seat. The idiot light needs to be populated with an incandescent light (not an LED!). Then I added the thermistor to the fuel sending unit in the tank. (Toyota made the truck with the wire going from the fuel sending unit to the connector under the passenger seat). Initially I went cheap and took one off of a 4runner in the junkyard and bent into shape for my truck (the 4unner and trucks have different shaped gas tanks). But later I splurged and got the actual SR5 sending unit off of eBay. I just got obsessive about it and wanted that feature in my truck.