DESCRIPTION
SERVICE MANUAL NUMBER 22
90-860074--1 FEBRUARY 2002
Page 5A-23
FUEL QUANTITY ACTUATOR AND SENSOR
Inside the electronic diesel pump the solenoid actuator (rotary actuator) for injected fuel
quantity control engages with the control collar through a shaft. Similar to the mechanically
governed fuel injection pump, the cutoff ports are opened or closed depending upon the
control collar’s position. The injected fuel quantity can be infinitely varied between zero and
maximum (e.g., for cold starting). Using an angle sensor (potentiometer) called the Fuel
Quantity Sensor the rotary actuator’s angle of rotation, and thus the position of the control
collar, are reported back to the ECM and used to determine the injected fuel quantity as a
function of engine speed. When no voltage is applied to the actuator, its return springs
reduce the injection quantity to zero.
75407
a
b
c
d
a -
EDI Injection Pump
b -
Fuel Quantity (Control-Collar Position) Sensor
c -
Control Collar
d -
Fuel Quantity Actuator
A failure of the Fuel Quantity Actuator circuit should set a Code P1220. A failure of the Fuel
Quantity Sensor should set a Code P1225.
