Maximum Engine Speed Sensor

Senses engine speed based on impulses from diagnostic terminal of ignition switching unit (EZL). ECU uses information to govern engine speed by changing electrical current to Electro-Hydraulic Actuator (EHA), which in turn controls differential pressure regulator. When engine reaches maximum RPM, ECU signals EHA to increase lower chamber pressure to system pressure, causing an interruption in fuel supply to injection valves. This will give a leaner fuel mixture. Maximum engine RPM signal is also sent to fuel pump relay to interrupt contact between circuits No. 30 and 87, and shut off fuel pump.