TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Fuel Injection Pump, Rotary (005-014)
Section 5 - Fuel System - Group 05
Page 5-47
Advance Timing Mechanism
Regulated pressure produced by a vane supply pump in
both fuel injection pumps is used to advance the timing as
the engine speed increases. A return spring is used to
retard the timing as the engine speed is reduced. If a spring
should break, the timing will go to the advance position,
resulting in torque loss, fuel knock, and possible engine
overheating.
Retarded (late) timing will result in torque loss, high fuel
consumption, and white to black smoke.
The Lucas CAV DPA/DPS advance timing mechanism uses
a check ball in the circuit which, if omitted during assembly,
will result in no timing advance. If the fuel injection pump
has been replaced or the mechanism has been removed to
fix a leak, the problem can be that the check ball is missing.
Electrical Shutoff Valves
The fuel injection pumps are equipped with electrical shutoff
valves. These solenoid-operated valves block the supply of
fuel to the high-pressure pumping and distribution com-
ponents.
The Bosch VE shutoff valve is located at the top rear of
the pump.
The Lucas CAV DPA/DPS shutoff valve is located at the
bottom rear of the pump.
Both 12- and 24-VDC activate-to-run and activate-to-stop
solenoids are available.
L-907
