TM 5-3895-382-24
When the engine is cranking, the fuel is pulled from the fuel
tank (12) through the water separator (9) by the fuel transfer
pump (8). When the fuel goes through the water separator,
any water in the fuel will go to the bottom of the bowl. The fuel
transfer pump sends the fuel at a low pressure to the fuel filter
(7). From the fuel filter, the fuel goes through the supply line
(6) to the fuel injection pump (10).
The fuel injection pump sends fuel through the high pressure
fuel lines (11) to each of the fuel injection nozzles (1). The fuel
injection nozzle sprays fuel into the cylinder. Fuel which is not
used by the fuel injection pump goes through the fuel return
line (5) to the inlet side of the fuel filter (7). Leakage from the
fuel injection nozzles flows through the fuel return line (2) to
the top of the fuel filter (7), back to the fuel tank (12), and
through the fuel return line (4).
The fuel injection pump needs fuel for lubrication. The
precision parts of the pump are easily damaged. For this
reason, the engine must not be started until the fuel injection
pump is full of fuel that is free of air.
The system must be primed when any part of the system is
drained of fuel. The following list contains examples of both
service and repairs when you must prime the system:
The fuel filter is changed.
The fuel line is removed.
The fuel injection pum p is removed.
Illustration 8
Fuel system components (left side)
Table 4
(1)
Fuel injection nozzle
(5)
Supply line
(2)
Fuel return line from fuel
(6)
Fuel return line from fuel
injection nozzles
injection pump
(3)
High pressure fuel lines
(7)
Fuel injection pump
(4)
Fuel filter
Illustration 9
Fuel system components (right side)
(8) Air inlet heater
(9) Fuel supply line
(10) Fuel transfer pump
There is a small filter screen in the fuel transfer pump (10).
The pump has a lever which is manually operated in order to
remove the air from the fuel system. In order to release air
from the system, the orifice in the cover of the fuel filter (4) is in
the inlet side of the filter. The orifice is connected to the fuel
tank by the fuel return line from the fuel filter (4).
The air inlet heater is an electrically operated device. The air
inlet heater ignites a controlled amount of diesel fuel in the inlet
manifold in order to heat the inlet air. A heater coil in the air
inlet heater expands a delivery valve holder in order to allow
the fuel to flow into the heater. The fuel is ignited by the hot
coil. The combustion heats the air which passes through the
air inlet manifold when the starter motor is operated.
The air inlet heater (8) is installed in the inlet manifold. The air
inlet heater is controlled by a remote mounted control switch.
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