[BHP231]

The wiring from the ecu to the dash is definitely not as it was from the factory. The only red connector I see goes to an earth point. I also see a thin black cable coming off the end of outside of the metal ecu box from a screw connection which has been cutoff. The guy who installed the engine tells me he didn’t disconnect anything under the dash with the motor change so I wonder if there is a connection in the motor or from the crank which send a signal to the ecu for revs which was not connected? If so where would the engine connection or sensor be?