WASHER-THRUST 1238187 - Caterpillar

Introduction
Illustration 1 g02511124
Typical example
(1) Primary fuel filter
(2) Secondary fuel filter
(3) Fuel Injection Pump
(4) Fuel transfer pump
(5) Fuel manifold (rail)
(6) Pressure relief valve
(7) Electronic unit injector
(8) Manifold connector
(9) Fuel cooler (if equipped)
(A) Fuel tank Fuel is drawn from the fuel tank to the 10 micron primary fuel filter and a water separator. The fuel then flows to the fuel transfer pump. The fuel transfer pump is part of the fuel injection pump.Fuel then flows from the fuel transfer pump to the 4 micron secondary fuel filter. Fuel flows from the secondary fuel filter to the fuel injection pump.At the fuel injection pump, the fuel is pumped at an increased pressure of up to 160 MPa (23200 psi) fuel manifold (rail).Fuel that has too high a pressure from the fuel manifold (rail) returns through the pressure relief valve to the return line. Fuel that is leak off from the electronic unit injectors flows to the return line. The fuel may then flow through a fuel cooler (if equipped) on the way back to the fuel tank.High Pressure Fuel System
Illustration 2 g02493876
Typical example
(1) Fuel injection pump
(2) Suction control valve for the fuel injection pump
(3) Pressure relief valve
(4) Fuel manifold (rail)
(5) Electronic unit injector
(6) Fuel pressure sensor
(7) Fuel transfer pump The fuel injection pump (1) feeds fuel to the high-pressure fuel manifold (rail) (4). The fuel is at a pressure of up to 160 MPa (23200 psi). A pressure sensor (6) in the high-pressure fuel manifold (rail) (4) monitors the fuel pressure in the high-pressure fuel manifold (rail). The ECM controls a suction control valve (2) in the fuel injection pump in order to maintain the actual pressure in the high-pressure fuel manifold at the desired level. The high-pressure fuel is continuously available at each injector (5). The ECM determines the correct time for activation of the correct electronic unit injector (5) which allows fuel to be injected into the cylinder. The leakoff fuel from each injector passes through an external pipe above the electronic unit injectors. The leakoff fuel then flows to a connector block on the left-hand side of the engine. A pipe is connected from the connector block in order to return the leakoff fuel to the fuel tank.Components of the Fuel Injection System
The fuel injection system has the following mechanical components:
Primary filter/water separator
Fuel transfer pump
Secondary fuel filter
Fuel injection pump
Fuel injectors
Fuel manifold
Pressure relief valve
Fuel pressure sensor
Fuel temperature sensor
Water in fuel sensorThe following list contains examples of both service and repairs when you must prime the system:
A fuel filter is changed.
A low-pressure fuel line is replaced.
The fuel injection pump is replaced.For the correct procedure to prime the fuel system, refer to Systems Operation, Testing and Adjusting, "Fuel System - Prime".Primary Filter/Water Separator
Illustration 3 g02848802
Typical example
The primary filter/water separator (1) is located between the fuel tank and the fuel transfer pump. The primary filter/water separator (1) provides a 10 micron filtration level.The primary filter/water separator can either be engine mounted or supplied loose. The primary filter/water separator is supplied with water in fuel sensor.