Fuel System - General Information - Gasoline and Diesel

Fuel System - Diesel Engine

The diesel fuel system consists of the following:

- Fuel tubes
- Vapor tube (midship fuel tank)
- Fuel filters (located on the engine and in the fuel conditioning module)
- Fuel level sensor
- Fuel tank filler pipe assembly
- Fuel tank
- Fuel tank selector switch (if equipped)
- Fuel tank selector valve (if equipped)
- High-pressure fuel system (located on the engine)
- Fuel conditioning module (located on the LH frame rail)
- Inertia Fuel Shutoff (IFS) switch (located on the RH side of the instrument panel)
- Low pressure fuel system (located between the fuel tank and the engine)

The fuel system for the high-pressure common rail direct injection turbocharged diesel engine:

- is controlled by the PCM.
- utilizes a fuel conditioning module, which contains an electric Fuel Pump (FP) and incorporates a fuel filter and water separator assembly.

The electric FP:

- draws fuel from the fuel tank.
- circulates fuel at low pressure through the 10 micron fuel conditioning module fuel filter and water separator to the engine fuel filter module, where the pressure is regulated. The fuel is filtered through the 4 micron engine fuel filter, then supplied to the high-pressure fuel injection pump. Fuel is returned from the injectors through the cylinder head fuel galleries and joins fuel return from the high-pressure fuel injection pump. The combined return fuel goes through the engine fuel cooler and back to the engine fuel filter module. The return fuel is re-circulated in the engine fuel filter module or returned back to the tank through the chassis lines and hoses based on engine demand.


Fuel Filter/Water Separator

The diesel engine is equipped with a fuel filter and water separator fuel conditioning module assembly. Drain the water from the fuel conditioning module at the recommended maintenance intervals. Refer to the Owner's Literature for the maintenance intervals.

A water in fuel indicator on the instrument panel will alert the operator. When the indicator glows continuously while the engine is running, drain the water from the fuel filter and water separator bowl as soon as possible to prevent damage to the fuel injection system.


Fuel Tank Selector Switch/Valve

If equipped, the fuel tank selector valve and fuel tank selector switch allows the use of 2 fuel tanks. When the fuel tank selector switch is in the front position, the fuel tank selector valve will allow fuel to flow from the auxiliary fuel tank. When the fuel tank selector switch is in the rear position, the fuel tank selector valve will allow fuel to flow from the aft-of-axle tank. The fuel gauge will read the correct amount of fuel in each tank depending on which tank is selected with the fuel tank selector switch.