The fuel transfer pump draws fuel from the fuel tank and through the water separator. When the fuel goes through the water separator, any water in the fuel will go to the bottom of the bowl. The fuel transfer pump sends the fuel at a low pressure to the fuel filter. From the fuel filter, the fuel goes through the supply line to the fuel injection pump.
The fuel injection pump sends fuel through the high pressure fuel lines to each of the fuel injectors. The fuel injector sprays the fuel into the cylinder. Fuel that is not injected flows through the fuel return line to the top of the fuel filter, back to the fuel tank.
The engine must not be started until the fuel injection pump is full of fuel that is free of air. The fuel injection pump requires fuel for lubrication. The precision parts of the pump are easily damaged without lubrication.
The fuel system must be primed when any of the following conditions occur:
- The fuel filter is changed.
- The fuel line is removed.
- The fuel injection pump is removed.
The fuel injection pump is a pressurized system that is totally enclosed. The pump sends the correct amount of fuel under high pressure at the correct time through the fuel injectors to the individual cylinders. The fuel injection pump regulates the amount of fuel that is delivered to the fuel injectors. This action controls the engine rpm by the governor setting or the position of the throttle control.
The fuel lines to the fuel injectors are equal lengths. This ensures even pressure and correct injection timing at each fuel injector.
During operation, extra fuel is used as coolant and lubricant for moving parts of the pump. The extra fuel is circulated through the pump housing. The extra fuel is then returned to the fuel tank.
The Delphi DP210 and DP310 fuel injection pumps must be serviced by an authorized Delphi technician. For repair information, contact your Caterpillar dealer or contact your Caterpillar distributor.
High idle and low idle of the fuel injection pump are factory set. Idle adjustments can not be made to the fuel pump. The Delphi DP310 fuel injection pump has a boost control. The Delphi DP210 and DP310 fuel injection pumps have an engine stop solenoid and a feature that vents air from the pump.
The Delphi DP210 and DP310 fuel injection pumps have a cold starting aid. The cold starting aid advances the timing of the pump when the engine is cold. The cold starting aid is electrically operated.
The cold start advance unit holds the timing of the fuel injection pump in an advance position when the engine is cold.
The coolant switch for the cold start advance unit is on the water temperature regulator housing on the left side of the engine.
When the engine is cold, the sender unit is energized in order to advance the fuel injection pump timing for the cold start operation. When the correct temperature is achieved the sender unit is de-energized and the fuel injection pump timing is returned to the normal operating position.
If the switch fails in the closed position, the engine will run with advanced fuel injection timing. The engine will have higher cylinder pressure and engine damage may result.
If the switch fails in the open position the engine will run with the fuel injection timing in the normal operating position. The engine will be more difficult to start. When the engine is cold the engine might emit white smoke.