spark JEEP WRANGLER 2008 JK / 3.G Owners Manual

FUEL REQUIREMENTS
All engines (except 5.7L engines) are de-
signed to meet all emissions regulations
and provide excellent fuel economy and
performance when using high quality un-
leaded “regular” gasoline having an oc-
tane rating of 87. The use of premium
gasoline is not recommended. Under normal conditions,
the use of premium gasoline will not provide a benefit
over high quality regular gasoline, and in some circum-
stances may result in poorer performance.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required. Poor quality gasoline can cause problems such as hard
starting, stalling and hesitations. If you experience these
symptoms, try another brand of gasoline before consid-
ering service for the vehicle.
Over 40 auto manufacturer’s worldwide have issued and
endorsed consistent gasoline specifications (the World-
wide Fuel Charter, WWFC) to define fuel properties
necessary to deliver enhanced emissions, performance,
and durability for your vehicle. The manufacturer recom-
mends the use of gasoline that meets the WWFC speci-
fications if they are available.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning gasoline referred to as “Reformulated Gasoline.”
Reformulated gasoline contains oxygenates, and are spe-
cifically blended to reduce vehicle emissions and im-
prove air quality.
336 STARTING AND OPERATING

The manufacturer supports the use of reformulated gaso-
line. Properly blended reformulated gasoline will pro-
vide excellent performance and durability for the engine
and fuel system components.
Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxy-
genates such as 10% ethanol, MTBE, and ETBE. Oxygen-
ates are required in some areas of the country during the
winter months to reduce carbon monoxide emissions.
Fuels blended with these oxygenates may be used in
your vehicle.
CAUTION!
DO NOT use gasolines containing Methanol. Use of
these blends may result in starting and drivability
problems and may damage critical fuel system
components.Problems that result from using methanol/gasoline
blends are not the responsibility of the manufacturer.
While MTBE is an oxygenate made from Methanol, it
does not have the negative effects of Methanol.
MMT In Gasoline
MMT is a manganese containing metallic additive that is
blended into some gasoline to increase the octane num-
ber. Gasoline blended with MMT offers no performance
advantage beyond gasoline of the same octane number
without MMT. Gasoline blended with MMT has shown
to reduce sparkplug life and reduce emission system
performance in some vehicles. The manufacturer recom-
mends that gasoline without MMT be used in your
vehicle. The MMT content of gasoline may not be indi-
cated on the gasoline pump, therefore, you should ask
your gasoline retailer if the gasoline contains MMT.
STARTING AND OPERATING 337
5

JUMP STARTING
If the vehicle has a discharged 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
dangerous if done improperly, so follow this procedure
carefully.WARNING!
Battery fluid is a corrosive acid solution; do not allow
battery fluid to contact eyes, skin or clothing. Don’t
lean over battery when attaching clamps or allow the
clamps to touch each other. If acid splashes in eyes or
on skin, flush contaminated area immediately with
large quantities of water.
A battery generates hydrogen gas which is flam-
mable and explosive. Keep flame or spark away from
the vent holes.
Do not use a booster battery or any other booster
source that has a greater than 12–volt system, i.e., Do
not use a 24–volt power source.
1. Remove all metal jewelry such as watch bands or
bracelets which might make an unintended electrical
contact.
WHAT TO DO IN EMERGENCIES 371
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WARNING!
Any procedure other than above could result in:
1. Personal injury caused by electrolyte squirting out
the battery vent;
2. Personal injury or property damage due to battery
explosion;
3. Damage to charging system of booster vehicle or
of immobilized vehicle.
WARNING!
•You should not try to start your vehicle by pushing
or towing.
•Do not connect the cable to the negative post of the
discharge battery. The resulting electrical spark
could cause the battery to explode.
•During cold weather when temperatures are be-
low freezing point, electrolyte in a discharged
battery may freeze. Do not attempt jump starting
because the battery could rupture or explode. The
battery temperature must be brought up above
freezing point before attempting jump start.
WHAT TO DO IN EMERGENCIES 373
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MAINTAINING YOUR VEHICLE
CONTENTS
Engine Compartment – 3.8L ...............378
 Onboard Diagnostic System — OBD II ........379
▫ Loose Fuel Filler Cap Message ............380
 Emissions Inspection And Maintenance
Programs ............................380
 Replacement Parts ......................382
 Authorized Dealer Service ................382
 Maintenance Procedures ..................383
▫ Engine Oil ..........................383 ▫
Drive Belts — Check Condition And Tension . . 386
▫ Spark Plugs .........................386
▫ Catalytic Converter ....................386
▫ Crankcase Emission Control System ........388
▫ Fuel Filter ..........................388
▫ Engine Air Cleaner Filter ................389
▫ Maintenance-Free Battery ................389
▫ Air Conditioner Maintenance .............390
▫ Power Steering Fluid Check ..............391
7

Drive Belts — Check Condition and Tension
Belt tension is controlled by means of an automatic
tensioner. No belt tension adjustments are required.
However, belt and belt tensioner condition should be
inspected at the specified intervals, and replaced if re-
quired. See your authorized dealer for service
At the mileage indicated in the Maintenance Schedule,
the condition of all the belts and tensioner should be
checked. Refer to Section 8 of this manual. Improper belt
tension can cause belt slippage and failure.
Belts should be inspected for evidence of cuts, cracks,
glazing, or frayed cords and replaced if there is indication
of damage, which could result in belt failure. Low
generator belt tension can cause battery failure.
Also, check belt routing to make sure there is no inter-
ference between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure engine perfor-
mance and emission control. New plugs should be in-
stalled at the mileage specified in the Maintenance Sched-
ule. Refer to Section 8 of this manual. The entire set
should be replaced if there is any malfunction due to a
faulty spark plug. Refer to Fluids, Lubricants, and Genu-
ine Parts in this section for spark plug information.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
converter as an emission control device.
Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
386 MAINTAINING YOUR VEHICLE

To minimize the possibility of catalytic converter dam-
age:
•Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
•Do not try to start the engine by pushing or towing the
vehicle.
•Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing.
•Do not idle the engine for prolonged periods during
very rough idle or malfunctioning operating condi-
tions.
•Do not allow vehicle to run out of fuel.NOTE:
Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
Crankcase Emission Control System
Proper operation of this system depends on freedom
from sticking or plugging due to deposits. As vehicle
mileage builds up, the PCV valve and passages may
accumulate deposits. If a valve is not working properly,
replace it with a new valve. DO NOT ATTEMPT TO
CLEAN THE OLD PCV VALVE!
Check ventilation hose for indication of damage or
plugging deposits. Replace if necessary.
Fuel Filter
A plugged fuel filter can cause hard starting or limit the
speed at which a vehicle can be driven. Should an
excessive amount of dirt accumulate in the fuel tank,
frequent replacement of the fuel filter which is mounted
in the fuel tank may be necessary.
388 MAINTAINING YOUR VEHICLE

FLUIDS, LUBRICANTS AND GENUINE PARTS
Engine
ComponentFluid, Lubricant, or Genuine Part
Engine Coolant MOPARAntifreeze/Coolant 5 Year/100,000 Mile Formula HOAT (Hybrid
Organic Additive Technology)
Engine Oil Use API Certified SAE 5W-20 Engine Oil, meeting the requirements of
DaimlerChrysler Material Standard MS-6395. Refer to your engine oil filler cap
for correct SAE grade.
Spark Plugs (3.8L Engine) RE14PLP5 (Gap 0.050 in [1.27 mm])
Oil Filter (3.8L Engine) MOPAROil Filter (P/N 04105409AC)
Fuel Selection 87 Octane
MAINTAINING YOUR VEHICLE 425
7

Perform Maintenance Every(Where time and mileage
are listed, follow the interval that occurs first.)
Maintenance Items MilesKilometers or Months
Change the transfer case fluid if using your vehicle for
any of the following: police, taxi, fleet, off-road or fre-
quent trailer towing. 60,000
100 000 60
Inspect and replace PCV valve if necessary. 90,000150 000 90
Flush and replace the engine coolant. 102,000170 000 60
Replace the ignition cables. 102,000170 000 102
Replace the spark plugs. 102,000170 000 102
Change the automatic transmission fluid, and filter(s). 120,000 200 000120
Replace accessory drive belt(s). 120,000200 000 120
MAINTENANCE SCHEDULES 433
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Sentry Key Programming................... 16
Sentry Key Replacement ................... 16
Service Assistance ....................... 437
Service Contract ......................... 439
Service Manuals ........................ 441
Setting the Clock .................. 224,236,251
Shift Lock Manual Override ................ 280
Shifting ............................... 279
Automatic Transmission ................. 281
Manual Transmission ................... 275
Shoulder Belt Upper Anchorage .............. 47
Shoulder Belts ........................... 41
Side Airbag ............................. 57
Signals, Turn ................... 99,207,421,422
Snow Chains (Tire Chains) ................. 329
Soft Top ........................... 141,168
Sound Systems (Radio) .................... 250
Spare Tire ............................. 367
Spark Plugs ............................ 386 Specifications
Fuel (Gasoline) ........................ 336
Oil ................................ 384
Speed Control (Cruise Control) .............. 102
Speedometer ........................... 206
Starting ............................... 271
Automatic Transmission ................. 271
Cold Weather ......................... 272
Engine Block Heater .................... 275
Engine Fails to Start .................... 273
Manual Transmission ................... 271
Remote .............................. 25
Steering Power ........................... 31 1,391
Tilt Column .......................... 101
Wheel Lock ........................... 14
Wheel, Tilt ........................... 101
Storage ............................ 1 18,419
Storage, Behind the Seat ................... 119
INDEX 459
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