The fuel injection system is responsible for supplying the diesel engine with fuel. To do so, the injection pump generates the pressure required for fuel injection. The fuel under pressure is forced through the high-pressure fuel-injection tubing to the injection nozzle which then injects it into the combustion chamber. The fuel injection system includes the following components and assemblies (see Figure
High pressure fuel injection lines
Electronic control unit
2.Injector Pump Gear
Injection Pump Parts Location
The combustion process in the diesel engine depends to a large degree upon the quantity of fuel which is injected and upon the method of introducing this fuel to the combustion chamber.
The most important criteria in this respect are the fuel-injection timing and the duration of injection, the fuel's distribution in the combustion chamber, the moment in time when combustion starts, the amount of fuel metered to the engine per degree crankshaft, and the total injected fuel quantity in accordance with the engine loading. The optimum interplay of all these parameters is decisive for the faultless functioning of the diesel engine.
Repair or Replacement of Injector Pump
To determine if replacement of the injection pump is necessary, perform the following procedure. See Figure
Flowchart for Replacement of the Injection Pump
Removal of Injector Pump
Remove the fuel injection pump as follows:
Remove access plug.
Turn the crankshaft to position the number one piston at top-dead-center (TDC). Then rotate engine counterclockwise approximately 155 until the injection pump keyway is at the 11 o'clock position. See Figure
The injection pump gear has two key slots. The slot with the shaft key should be at the 11:00 o'clock position.
Slightly rotate the engine in a clockwise direction until the engine is at number one top-dead-center (TDC) and then in a counterclockwise direction until the dial indicator stops moving (20-255 before top-dead-center).
Set the dial gage to zero and rotate the crankshaft clockwise until the marks on the pulley and the front cover are aligned. See Figure
1.Timing Mark Location
Pulley and Front Cover Alignment
Check that the dial gage reading is at 0.70 mm (0.028 in.). If the reading is different, adjust the pump position slightly by rotating it to the left or right until the required reading is obtained.