The gauges were dead because the BUS was down due to a blown fuse. Usually on late model ZJs that is due to the downstream O2 sensor harness coming loose from it's retainer and rubbing on the driveshaft until it causes a dead short to ground. With that fuse replaced you got the BUS back up but it may have indeed shorted the PCM.
Do you have spark now? Do you have injector pulse? You can have fuel pressure, but if the injectors aren't opening, you won't start.
