The fuel injectors are located in the center of the combustion chambers
in the cylinder head between the rocker arm assemblies. The glow plug
system and fuel injection system are controlled through the Powertrain
Control Module (PCM) and Fuel Injection Control Module (FICM).
Fuel is drawn from the fuel tank by a frame-mounted electric fuel pump.
The fuel pump provides pressurized fuel to the engine and is
electronically controlled by the fuel pump PCM relay. The fuel pump
contains a pressure relief valve for overpressure protection in the event
of restricted flow.
Lubrication system
It is important to change the engine oil at the recommended service
intervals, because oil viscosity is important in maintaining the oil
pressure required to actuate the fuel injectors. Extended oil change
intervals can negatively affect engine performance, fuel economy and
engine life. Refer to the engine oil specification chart located under
Engine oil specificationsin theMaintenance and specifcations
chapter.
Fast start glow plug system
The glow plug system consists of:
•eight glow plugs
•the glow plug control module (GPCM)
•engine oil temperature (EOT) sensor
•barometric pressure (BARO) sensor
The glow plug system is
electronically controlled by the
PCM. The GPCM energizes the glow
plugs immediately after the ignition
is placed in the ON position, then determines how long the glow plugs
will be on according to the EOT and BARO sensors. The required time
for the glow plugs to be energized decreases as the engine oil
temperature and barometric pressure increase.
Engine cooling system
The cooling system contains an engine oil cooler which is mounted in the
center valley of the engine. The cooler’s function is to regulate engine oil
temperature.
Introduction
4
Water in fuel
During refueling, it is possible for
water-contaminated diesel fuel to be
pumped into your tank. Your vehicle
fuel system is equipped with a fuel
filter/water separator to remove water from the fuel. The WATER IN
FUEL light will illuminate when the ignition is turned to START (as part
of the light function check) and when the HFCM has a significant
quantity of water in it.
If the light illuminates when the engine is running, stop the vehicle as
soon as safely possible, shut off the engine, then drain the HFCM. Refer
toDraining the HFCM and changing the fuel filtersin the
Maintenance and specificationssection of this supplement for the
drain procedure. Allowing water to stay in the system could result in
extensive damage to, or failure of, the fuel injection system.
Do not drain the water separator while the engine is running.
Fuel may ignite if the separator is drained while the engine is
running or the vehicle is moving.
Engine air filter
The engine air filter warning light
illuminates when the air filter
restriction gauge reaches the
CHANGE FILTER mark.
The condition should be verified by inspecting the underhood air filter
restriction gauge; the warning light is only a secondary indicator. Always
use the underhood air filter restriction gauge to determine when the air
filter element needs to be changed.
The vehicle may be driven with the engine air filter warning light
illuminated/or when the underhood air filter restriction gauge has moved
to the CHANGE FILTER mark for up to 400 km (250 miles) without
damaging the engine or related components. However, the air filter
element must be replaced at the earliest opportunity. Refer toAir filter
restriction gauge (if equipped)in this section of the supplement for
more information.
Instrumentation
7
