FINAL DRIVE GP 3021688 - Caterpillar

Schematic of the Automatic Timing Advance Unit for the Bosch EPVE Fuel Injection Pump
Some fuel injection pumps have an automatic timing advance unit. The automatic timing advance unit holds the timing of the fuel injection pump in an advance position when the engine is cold.
It is important that the electrical connections to the sender unit are connected correctly. If the cold start advance unit fails to operate correctly, engine damage may result because the engine timing will be fully advanced for normal engine operation.
The automatic timing advance unit is on the rear of the timing case on the left side of the engine.
Damage to the engine will occur if the engine is load tested at more than 80 percent of full load with the cold start advance unit disconnected.
Illustration 1 g00523698
Bosch fuel injection pump
(1) Fuel injection pump
(2) 3 Amp wire
(3) Engine stop solenoid
(4) Sending unit
(5) 3 Amp wire
(6) Automatic timing advance unit
(7) 6 Amp wire
(8) Typical example of a start switch As the engine begins to reach normal operating temperature, the automatic timing advance unit energizes. By energizing, the fuel injection pump timing is retarded to the correct timing for normal operation.Test the Automatic Timing Advance Unit on the Bosch EPVE Fuel Injection Pump
Illustration 2 g00560507
Cold Starting Aid (Bosch)
(1) Connection for the advance lever to the pull rod
(2) Pull rod
(3) Electrical connection
(4) Element
(5) Advance lever
(6) Mounting bracket
(7) Battery Note: Advance lever (5) of the fuel injection pump is set at the factory in order to advance the injection timing when the engine is cold. The automatic timing advance unit must be energized, when the static timing of the fuel injection pump is checked.Note: Do not release connection (1) for the advance lever to the pull rod. The setting of the advance lever that is set at the factory will not be maintained.
Illustration 3 g00560681
(8) Locking plate
(9) Locking bolt Note: Before the crankshaft is turned or before the fuel injection pump is turned, loosen locking bolt (9). Put locking plate (8) under locking bolt (9).
Remove the fuel injection pump from the engine. Refer to Disassembly and Assembly, "Fuel Injection Pump - Remove".
The positive terminal of battery (7) is connected to electrical connection (3) of the automatic timing advance unit by a wire.
The negative terminal of battery (7) is connected to mounting bracket (6) of the automatic timing advance unit by a wire.
Allow a minimum of five minutes for the wax in element (4) to expand before the static timing is set.
Turn the pump shaft in the direction of rotation. Advance lever (5) will move toward connection (1). There should be zero advance timing in this position. Pull rod (2) should be fully extended. Only trained personnel should perform any adjustments that are required. Note: The pump can be removed and the pump can be installed without energizing the automatic timing advance unit if the following conditions exist:
The performance of the fuel injection pump is correct.
The static timing adjustment is not necessary.