REMOVAL
REMOVAL/INSTALLATION
The cascade overflow valve is not serviced separately.
SENSOR-WATER IN FUEL
DESCRIPTION
The Water-In-Fuel (WIF) sensor (5) is located on the
side of the fuel filter/water separator canister.
OPERATION
The sensor sends an input to the Engine Control Module (ECM) when it senses water in the fuel filter/water sep-
arator. As the water level in the filter/separator increases, the resistance across the WIF sensor decreases. This
decrease in resistance is sent as a signal to the ECM and compared to a high water standard value. Once the value
reaches 30 to 40 kilohms, the ECM will activate the water-in-fuel warning lamp through CCD bus circuits. This all
takes place when the ignition key is initially put in the ON position. The ECM continues to monitor the input while
the engine is running.
REMOVAL
The Water-In-Fuel (WIF) sensor is located at the side of fuel filter/water separator canister. Refer to Fuel Filter/
Water Separator Removal/Installation for WIF sensor removal/installation procedures.
CIRCUIT - FUEL DRAIN
OPERATION
The Fuel Drain Circuit incorporates several sources of fuel return. Fuel travels from the fuel tank (via the fuel trans-
fer pump) and is forced through the fuel filter. This fuel then travels into the fuel injection pump. It then goes to a
fuel drain line and returns back to the fuel tank.
The fuel that flows to the fuel pump is pressurized by a gear pump and internally transferred to the fuel injection
pump. At this point the fuel is channeled into two passages. One passage sends fuel to the FCA (Fuel Control
Actuator). The other passage sends fuel to the cascade overflow valve. The overflow valve sends some fuel to a
lubrication passage. The rest of the fuel is sent to a drain passage which connects to an external fuel line.
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FUEL DELIVERY - DIESEL
DR/DH