Fuel system
The fuel is drawn with help of the fuel feed pump (1) through the tank unit (2), via fuel pre- filter (4) and
water separator (5) into the fuel filter housing (3).
The fuel is then routed through the engine ECUs cooling loop (6) to the overflow valve (7), where the
fuel from the tank is mixed with the fuel returned from the fuel channel (8) in the cylinder head, and then
forward to the suction side of the fuel feed pump (1). The fuel feed pump (1) press fuel to the fuel filter
housing (3), through the main filter (9) to the cylinder head fuel channel (8). This channel provides every
unit injector (10) with fuel via a ring formed passage around every unit injector in the cylinder head. The
overflow valve (7) regulates the fuel feed pressure to the unit injectors.
Fuel feed pump valves
The fuel feed pump has two valves: Safety valve (11), which allows fuel to flow back to suction side when
the fuel pressure become too high e.g. when the fuel filter is clogged. Check valve (12) opens when the
hand pump in the filter housing (13) is used.
Automatic deaeration
If air has entered the system, automatic deaeration occurs when the engine is started. The air is pushed
through the deaeration valve (14) down to the tank via the fuel return hose (15) from cylinder head.
Deaeration of fuel filters when changing filters is controlled by the valves (19), (25) and (14) in the filter
housing.
Manual hand pump
The manual hand pump (13) in the filter housing is used to pump fuel (non-running engine), when the fuel
system is empty. The check valve (24) for the hand pump is placed within the fuel filter housing.
Manual water drain
WIF (water in fuel) sensor (16) will via the ECU give an indication on the instrument panel. This indicates
that it is necessary to manually drain the water-separator (5) using the drain valve (18).
Miscellaneous
(20) Fuel pressure measuring point used for fault localization
(21) Pressure indicator
(22) Optional bowl heater
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