I'm using a stock TJ tank and fuel pump in my 95 YJ. I'm installing a 5.0 and using a Ford Motorsports harness. I don't have a FSM for a TJ, so I could use a little help sorting the 4 wires coming from the TJ fuel pump. I know the two smaller ones are for the fuel gauge and the larger ones are for the pump.. To find out which one is positive and which is negative pull the wire loom back and look @ the colors of the wires. Doing it this way will make the pump run constantly, because on start up it only runs for a second or 2, this way you can check pressure to the fuel rail w/o the engine having to run in the event you can't get the engine to start.
Well, after doing just that, I still have no fuel going to the engine. The fuel gauge is working again, and when the key is turned to ON, I hear the fuel pump prime. The issue I am having is I think the harness is aftermarket because the wire colors don't match the wiring diagram, so I don't know what the hot wire to the pump is.. 2. Ground at fuel pump relay pin C8 from PCM (with ignition switch on) 3. 12VDC at fuel pump relay pin C10 (from PDC fuse 23) 4. 12VDC at fuel pump pin 4 (with ignition on). Refer to wiring diagram 8W-30-3. All this info is based on 2006 model. If you have a different year, then you need to find it in the wiring diagrams and follow it through.