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.
Engine governed speed
The engine governor is controlled by the PCM. The PCM controls fuel
input to limit maximum engine speed. It will not, however, prevent
engine overspeeding resulting from downshifting at high vehicle speed or
by descending steep grades at too high a vehicle speed for the selected
transmission gear.
For maximum vehicle speed in various gears, refer toManual
transmission shift speedsin theDriving tipschapter. Do not exceed
3,600 rpm. Maximum engine governed speed is 4,000 rpm depending on
engine load. Excessive rpm can only be achieved by manually
downshifting at too high of a vehicle speed.
Operating the engine beyond the governed speed can cause
severe engine damage.
Diesel information
5
The complexity of the Diesel engine makes it so the owner is
discouraged from attempting to perform maintenance other than the
services described in this supplement.
If you experience difficult starting, rough idling, excessive exhaust
smoke, a decrease in engine performance or excess fuel consumption,
perform the following checks:
•a plugged air inlet system or engine air filter element.
•water in the fuel filter/water separator.
•a clogged fuel filter.
•contaminated fuel.
•air in the fuel system, due to loose connections.
•an open or pinched sensor hose.
•low engine oil level.
•wrong fuel or oil viscosity for climactic conditions.
If these checks do not help you correct the engine performance problem
you are experiencing, consult an authorized dealer.
FUELING
Do not use starting fluid such as ether or gasoline in the Diesel
air intake system. Such fluids can cause immediate explosive
damage to the engine and possible personal injury.
If you fuel your vehicle at a truck stop, you may notice that the fuel
nozzle may shut off every 5–10 seconds. This is due to the flow rates
being designed for larger heavy duty trucks. You may have to fuel at a
slower rate (don’t depress the nozzle trigger fully).
Do not run your Diesel vehicle out of fuel as this will allow air to enter
the fuel system which will make restarting difficult. Longer engine
cranking time may be required once air is in the fuel system. If air enters
the fuel system (either through running the fuel tank(s) empty or during
a fuel filter change), the engine will self-purge the trapped air once it
starts running. The engine may run roughly and produce white smoke
while air is in the fuel system; this is normal and should stop after a
short time.
Minor troubleshooting guide
39
