Maximum Engine Speed

ECU senses engine speed based on impulses from "TD" terminal of the ignition switching unit. Engine speed is limited by changing current to the differential pressure regulator from ECU. Lower chamber pressure is increased to system pressure and fuel supply to injection valves is interrupted.

The fuel pump relay also receives a maximum engine RPM signal. This signal interrupts the contact between circuits No. 30 and 87, which shuts off the fuel pump.