For performance tuners using the 4M51 in marine or off-road racing, pinout work is essential for ECU cloning.
Unlike common-rail, the 4M51 uses a with electronic spill valve timing. Each cylinder’s injector driver (B16–B19) triggers a solenoid on the pump, not a direct injector. Failure of any driver results in misfire but not total stall due to mechanical pump backup. mitsubishi 4m51 ecu pinout work