Ford 2002 Excursion Owner's Manual page 5

Fast start glow plug system
The glow plug system consists of:
eight glow plugs
the glow plug relay
engine oil temperature (EOT) sensor
barometric pressure (BARO) sensor
The glow plug system is electronically controlled by the PCM. The PCM
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 to
the side of the cylinder block. 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 to the "Transmission
shift speed" chart in the Driving tips chapter. Do not exceed 3,600 rpm.
Maximum engine governed speed is 3,000–4,000 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