Diesel Injection Pump
The high pressure diesel injection pump is mounted at top of engine, below intake manifold. The pump is gear-driven by camshaft. Pump precisely governs time and amount of fuel injection based on PCM controlled fuel solenoid and injector timing stepper motor.
Electrical controls mounted on injection pump are used by the PCM to control fuel flow and injector timing. These include an engine shut-off solenoid. This solenoid blocks fuel from entering charging passage. The pump cam sensor, on top of injection pump, detects RPM of the pulse ring. It also includes a fuel temperature sensor. These signals help PCM control amount of fuel delivery and injector timing. An injector timing stepper motor advances or retards injector timing. PCM controls amount of fuel delivered through fuel solenoid driver which operates fuel solenoid, mounted at front of injection pump. See Fig 1.
Fuel under regulated low pressure enters rotary fuel metering valve and into a charging passage. As pump shaft rotates, fuel is directed at high pressure through each delivery pipe to an injector.