Recently finished a LS 4.8L/4L60E swap in my '72 production date FJ40. Used a PSI wiring harness for the engine. I can't get the factory gauges to work correctly since. In particular, the oil pressure gauge, using the OE sender, pegs then drops to 0. The sender is tee'd with a mechanical gauge so I know I have 40+ lbs. psi. Don't expect the water gauge to read correctly because of a mismatched sender. Can't get the fuel gauge to read at all, needle doesn't budge off E. Any suggestions? Am I missing some resistance somewhere since I no longer have the voltage regulator or ignition coil resister due to the stand-alone engine wiring?