SPACER 6G9696 - Caterpillar

Illustration 1 g00823125
Fuel system schematic
Illustration 2 g00823139
Fuel system schematicThe fuel supply circuit is a conventional design for engines with fuel injection. The fuel supply circuit uses a fuel transfer pump to deliver fuel from the fuel tank to the electronic fuel injectors. The transfer pump is a fixed displacement gear pump.The fuel flows from the tank into the fuel/water separator. The fuel flows from the fuel/water separator into the fuel transfer pump. The fuel transfer pump supplies fuel to the cored passages of the ADEM II Electronic Control Module (ECM) (if equipped). This cools the module.The fuel transfer pump supplies fuel to the fuel filters before entering the fuel supply manifold. A fuel priming pump is located on the fuel filter base in order to fill the system. The system will need to be refilled after the fuel filters are changed. The system will also need to be refilled when the fuel injectors are replaced.The fuel flows continuously from the fuel supply manifold through the fuel injectors. The fuel flows when either the supply or the fill port in the injector is not closed by the injector body assembly plunger. The fuel that is not injected into the cylinder is displaced by the plunger and the fuel is returned to the fuel return manifold. A pressure regulating valve is at the end of the fuel return manifold. The pressure regulating valve controls the entire fuel system pressure. This provides proper filling of the fuel injectors. Refer to the Electronic Fuel Injector for a complete explanation of the injection process.The fuel passes through a fuel cooler that is mounted near the fan of the radiator. The fuel is then returned to the fuel tank. The fuel system utilizes an electronically controlled mechanically actuated fuel injector in order to provide total electronic control of injection timing. The injection timing is varied in order to optimize the engine's performance. This is a result of engine operating conditions.The engine speed is controlled by adjusting the duration of injection. The speed sensor timing ring is part of the rear gear group which provides information to the electronic control module (ECM). The signal is picked up by the engine speed/timing sensor. This information is for detection of crankshaft position and engine speed. Other information and this data allows the ECM to correctly send a signal to the injector solenoids. The fuel injector's solenoid is energized in order to begin fuel injection. The fuel injector's solenoid is de-energized in order to end fuel injection. Refer to the Electronic Fuel Injector.