2008 JEEP GRAND CHEROKEE engine

Normal Starting Ð Gasoline Engines
The gear selector must be in the ªNº (Neutral) or ªPº
(Park) position before you can start the engine. Apply the
brakes before shifting into any driving gear.
NOTE:Normal starting of either a cold or a warm
engine is obtained without pumping or depressing the
accelerator pedal.
Do notpress the accelerator. Use the Fob with Integrated
Key to briefly turn the ignition switch to the START
position and release it as soon as the starter engages. Thestarter motor will continue to run, and it will disengage
automatically when the engine is running. If the engine
fails to start, the starter will disengage automatically in 10
seconds. If this occurs, turn the ignition switch to the
LOCK position, wait 10 to 15 seconds, then repeat the
normal starting procedure.
Extremely Cold Weather (below220ÉF or229ÉC)
To insure reliable starting at these temperatures, use of an
externally powered electric engine block heater (available
from your dealer) is recommended.
276 STARTING AND OPERATING

If Engine Fails to Start
WARNING!
²Never pour fuel or other flammable liquids into
the throttle body air inlet opening in an attempt to
start the vehicle. This could result in a flash fire
causing serious personal injury.
²Do not attempt to push or tow your vehicle to get
it started. Vehicles equipped with an automatic
transmission cannot be started this way. Unburned
fuel could enter the catalytic converter and once
the engine has started, ignite and damage the
converter and vehicle. If the vehicle has a dis-
charged battery, booster cables may be used to
obtain a start from a booster battery or the battery
in another vehicle. This type of start can be dan-
gerous if done improperly. Refer to Section 6 of
this manual for proper jump starting procedures
and follow them carefully.If the engine fails to start after you have followed the
ªNormal Startingº or ªExtreme Cold Weatherº proce-
dures, it may be flooded. To clear any excess fuel, push
the accelerator pedal all the way to the floor and hold it.
Then, turn the ignition switch to the START position and
release it as soon as the starter engages. The starter motor
will disengage automatically in 10 seconds. Once this
occurs, release the accelerator pedal, turn the ignition
switch to the LOCK position, wait 10 to 15 seconds, then
repeat the normal starting procedure.
CAUTION!
To prevent damage to the starter, wait 10 to 15
seconds before trying again.
STARTING AND OPERATING 277
5

After Starting
The idle speed is controlled automatically and it will
decrease as the engine warms up.
Normal Starting Ð Diesel Engines
Observe the following when the engine is operating.
²All message center lights are off.
²Malfunction Indicator Light (MIL) is off.
²Low Oil Pressure Light is off.
Cold Weather Precautions
Operation in ambient temperature below 32ÉF (0ÉC) may
require special considerations. The following chart sug-
gest these options:
*No. 1 Ultra Low Sulfur Diesel Fuel (ULSD) should only
be used where extended arctic conditions (-10ÉF/-23ÉC)
exist.
278 STARTING AND OPERATING

NOTE:
²Use of Climatized ULSD Diesel Fuel or Number 1
ULSD Diesel Fuel results in a noticeable decrease in
fuel economy.
²Climatized ULSD Diesel Fuel is a blend of Number 2
ULSD and Number 1 ULSD Diesel Fuels which re-
duces the temperature at which wax crystals form in
fuel.
NOTE:This engine requires the use ofªUltra Low
Sulfur Diesel Fuel.ºUse of incorrect fuel could result in
exhaust system damage. Refer to ªFuel Requirementsº in
this section for further details on fuel recommendations.
Battery Blanket Usage
A battery loses 60% of its cranking power as the battery
temperature decreases to 0ÉF (-18ÉC). For the same de-
crease in temperature, the engine requires twice as much
power to crank at the same RPM. The use of 120 VAC
powered battery blankets will greatly increase startingcapability at low temperatures. Suitable battery blankets
are available from your authorized Mopartdealer.
Engine Starting Procedure
WARNING!
NEVER pour fuel or other flammable liquid into the
air inlet opening in an attempt to start the vehicle.
This could result in a flash fire causing serious
personal injury.
1. The gear selector must be in the ªNº (Neutral) or ªPº
(Park) position before you can start the engine.
2. Turn the ignition key to the ON position.
3. Watch for the ªGlow Plug Indicator Lightº in the
instrument cluster. Refer to ªInstrument Clusterº in
Section 4. It will glow for two to ten seconds or more,
STARTING AND OPERATING 279
5

depending on engine temperature. When the ªGlow Plug
Indicator Lightº goes out, the engine is ready to start.
4. Tip Start Feature
Do notpress the accelerator. Use the Fob with Integrated
Key to briefly turn the ignition switch to the START
position and then release it. The starter motor will
continue to run, and it will automatically disengage
when the engine is running.
NOTE:The starter motor may run up to 30 seconds in
very cold conditions until the engine is started. The
starter can be disengaged by turning the ignition key to
the OFF position, if required.
5. After the engine starts, allow it to idle for approxi-
mately 30 seconds before driving. This allows oil to
circulate and lubricate the turbocharger.
Avoid prolonged idling in ambient temperatures below
0ÉF (-18ÉC). Long periods of idling may be harmful toyour engine because combustion chamber temperatures
can drop so low that the fuel may not burn completely.
Incomplete combustion allows carbon and varnish to
form on piston rings and injector nozzles. Also, the
unburned fuel can enter the crankcase, diluting the oil
and causing rapid wear to the engine.
Engine Warm-Up
Avoid full throttle operation when the engine is cold.
When starting a cold engine, bring the engine up to
operating speed slowly to allow the oil pressure to
stabilize as the engine warms up.
NOTE:High-speed, no-load running of a cold engine
can result in excessive white smoke and poor engine
performance. No-load engine speeds should be kept
under 1,200 rpm during the warm-up period, especially
in cold ambient temperature conditions.
280 STARTING AND OPERATING

If temperatures are below 32ÉF (0ÉC), operate the engine
at moderate speeds for 5 minutes before full loads are
applied.
Engine Idling - In Cold Weather
Avoid prolonged idling in ambient temperatures below
0ÉF (-18ÉC). Long periods of idling may be harmful to
your engine because combustion chamber temperatures
can drop so low that the fuel may not burn completely.
Incomplete combustion allows carbon and varnish to
form on piston rings and injector nozzles. Also, the
unburned fuel can enter the crankcase, diluting the oil
and causing rapid wear to the engine.
Stopping The Engine
Before turning off your turbo diesel engine, always
allow the engine to return to normal idle speed and runfor several seconds. This assures proper lubrication of
the turbocharger. This is particularly necessary after
any period of hard driving.
Idle the engine a few minutes before routine shutdown.
After full load operation, idle the engine 3 to 5 minutes
before shutting it down. This idle period will allow the
lubricating oil and coolant to carry excess heat away from
the combustion chamber, bearings, internal components,
and turbocharger. This is especially important for turbo-
charged, charge air cooled engines.
The following chart should be used as a guide in deter-
mining the amount of engine idle time required to
sufficiently cool down the turbocharger before shut
down, depending upon the type of driving and the
amount of cargo.
STARTING AND OPERATING 281
5

ENGINE BLOCK HEATER Ð IF EQUIPPED
The engine block heater warms engine coolant and
permits quicker starts in cold weather. Connect the heater
cord to a ground-fault interrupter protected 110-115 volt
AC electrical outlet with a grounded, three-wire exten-
sion cord.
Use the heater when temperatures below 0ÉF (-18ÉC) are
expected to last for several days.
The block heater must be plugged in at least one hour to
have an adequate warming effect on the coolant.The engine block heater cord is located:²3.7L/4.7L Engine Ð coiled and strapped to the engine
oil dipstick tube.
²5.7L Engine Ð bundled and fastened to the injector
harness.
²3.0L Diesel Engine Ð on the passenger side of the
vehicle mounted on a stud between the fresh airbox
and coolant reservoir.
WARNING!
Remember to disconnect the cord before driving.
Damage to the 110-115 volt AC electrical cord could
cause electrocution.
STARTING AND OPERATING 283
5

AUTOMATIC TRANSMISSION
CAUTION!
Damage to the transmission may occur if the follow-
ing precautions are not observed:
²Shift into P (Park) only after the vehicle has come
to a complete stop.
²Shift into or out of R (Reverse) only after the
vehicle has come to a complete stop and the engine
is at idle speed.
²Do not shift from R (Reverse), P (Park), or N
(Neutral) into any forward gear when the engine is
above idle speed.
²Before shifting into any gear, make sure your foot
is firmly on the brake pedal.
WARNING!
It is dangerous to shift the selector lever out of P
(Park) or N (Neutral) if the engine speed is higher
than idle speed. If your foot is not firmly on the
brake pedal, the vehicle could accelerate quickly
forward or in reverse. You could lose control of the
vehicle and hit someone or something. Only shift
into gear when the engine is idling normally and
when your foot is firmly on the brake pedal.
Shift Lock Manual Override Ð If Equipped
Your vehicle may be equipped with a shift lock manual
override. The manual override may be used in the event
that the shift lever should fail to move from Park with the
key in the ON position and the brake pedal depressed. To
operate the shift lock manual override, perform the
following steps:
284 STARTING AND OPERATING