I posted fuel cell info on the pre 88 page. I’m going to try the 89 and up. I put an rci cell in my truck this is what I have so far. This is a 10 gallon cell with a Holley sniper in tank pump. Still in the working stages. But I’m able to start the truck. My question is the sending unit! I tested the wiring one is ground I think is green. Hard to tell.
There’s two wires with stripes maybe white and black. It’s hard to tell. I believe one is for the low fuel light because it blinks when I tested it. If I hook the other white wire to my rci sending unit and ground it, the gauge doesn’t work. But if I touch the low fuel light wire to the sender hot,the gauge works. Is this the correct way? By the way it works backwards says how’s full on empty.

 

Yes, most fuel cells have a GM style sending unit. They are backwards to Toyota. I installed one in mine several years ago and can't remember which wire went to what (sorry), but I think something like 3 ohms is empty and 110 ohms is full on Toyota sending units and it is the opposite on GM style units. I know I used the factory wiring and did not add any new wires. I just have to remember that now, "E" means I have enough fuel and "F" means I need to fill up.

 

I figured it was a GM unit. The only way I can get it to work was to tie the two striped wires together and the ground wire. I don’t know if it’s right