XJ4life92

So I'm in the middle of this swap. Changing from obd1 to obd2 and from the 4.0 to the 5.2. Been messing with all the wiring and finding out what is needed to get it to run. It appears that I need to keep the body controller, the gauges, and whatever is in the rear of the zj (lamp module?) Connected to make the pcm run the engine. I have the engine harness and the dash harness cut down to just a few wires to run it....but it seems that the gauge cluster is now dead....it's unresponsive even though I'm applying power, grounds and data to the correct wires. It was functioning and now it's not... even though it doesn't work, I still need it plugged in for the pcm to let the engine run. If I unplug it...it runs for a few seconds then shuts off. So now having a dead gauge cluster....it's there a way to trick the pcm into thinking the modules are connected? Also I wanna keep the 92 stock gauges and make them work with the obd2 computer....or run aftermarket gauges
... anybody know any of these things?