engine JEEP WRANGLER 2006 TJ / 2.G Service Manual

premium gasoline will provide no benefit over high
quality regular gasoline, and in some circumstances 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 world wide 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 is spe-
cifically blended to reduce vehicle emissions and im-
prove air quality.
The manufacturer strongly supports the use of reformu-
lated gasoline. Properly blended reformulated gasoline
will provide 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.
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Fuel System Cautions
CAUTION!
Follow these guidelines to maintain your vehicle’s
performance:
•The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine performance,
damage the emission control system.
•An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.
•The use of fuel additives which are now being sold as
octane enhancers is not recommended. Most of these
products contain high concentrations of methanol. Fuel system damage or vehicle performance problems
resulting from the use of such fuels or additives is not
the responsibility of the manufacturer.
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
Carbon Monoxide Warnings
WARNING!
Carbon monoxide (CO) in exhaust gases is deadly.
Follow the precautions below to prevent carbon
monoxide poisoning:
•Do not inhale exhaust gases. They contain carbon
monoxide, a colorless and odorless gas which can kill.
Never run the engine in a closed area, such as a
garage, and never sit in a parked vehicle with the
232 STARTING AND OPERATING

engine running for an extended period. If the vehicle is
stopped in an open area with the engine running for
more than a short period, adjust the ventilation system
to force fresh, outside air into the vehicle.
•Guard against carbon monoxide with proper mainte-
nance. Have the exhaust system inspected every time
the vehicle is raised. Have any abnormal conditions
repaired promptly. Until repaired, drive with all side
windows fully open.
•Keep the swing gate closed when driving your vehicle
to prevent carbon monoxide and other poisonous
exhaust gases from entering the vehicle.
FUEL FILLER CAP (GAS CAP)
The fuel cap is located on the left side of the vehicle. If the
fuel cap is lost or damaged, be sure the replacement cap
is for use with this vehicle.
Fuel Filler Cap Location
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CAUTION!
Damage to the fuel system or emission control
system could result from using an improper fuel cap
(gas cap). A poorly fitting cap could let impurities
into the fuel system. Also, a poorly fitting after-
market cap can cause the MIL (Malfunction Indica-
tor Light) to illuminate, due to fuel vapors escaping
from the system.
•Turn the engine off.
•Rotate the fuel cap to the left to remove.
•To replace the cap, insert it into the filler neck and
tighten the cap about 1/4 turn until you hear two
clicks. This is an indication that the cap is properly
tightened.
•Make sure that the fuel cap tether strap is not caught
under the fuel cap.
CAUTION!
To avoid fuel spillage and overfilling, do not “top
off” the fuel tank after filling.
NOTE: When the fuel nozzle “clicks” or shuts off, the
fuel tank is full.
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WARNING!
•Remove the fuel cap (gas cap) slowly to prevent
fuel spray from the filler neck which may cause
injury.
•The volatility of some gasoline may cause a
buildup of pressure in the fuel tank that may
increase while you drive. This pressure can result
in a spray of gasoline and/or vapors when the cap
is removed from a hot vehicle. Removing the cap
slowly allows the pressure to vent and prevents
fuel spray.
•Never have any smoking materials lit in or near
the vehicle when the fuel cap is removed or the
tank filled.
•Never add fuel to the vehicle when the engine is
running.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle. You
could be burned. Always place gas containers on the
ground while filling.
Locking Fuel Filler Cap (Gas Cap) — If Equipped
•
Turn the engine off.
•Insert the ignition key into the fuel cap, and turn the
key to the right to unlock the fuel cap. Rotate the fuel
cap to the left to remove.
•To replace the cap, insert it into the filler neck and
tighten the cap about 1/4 turn until you hear two
clicks. This is an indication that the cap is properly
tightened.
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Engine/
Transmis- sion Model GVWR (Gross
Vehicle Wt. Rat-ing) GCWR (Gross
Combined Wt. Rating) Frontal Area Max. GTW
(Gross TrailerWt.) Max. Tongue
Wt. (See Note 1)
2.4L/
Manual 4,350 lbs (1 973
kg) 5,350 lbs (2 427
kg) 25 Sq. Ft.
(2.32 square meters) 1,000 lbs (453
kg) 100 lbs (45 kg)
4.0L/All 4,250 lbs (1 928 kg) 6,250 lbs (2 835
kg) 25 Sq. Ft.
(2.32 square meters) 2,000 lbs (907
kg) 200 lbs (91 kg)
4.0L/
Automatic Unlim-
ited 4,600 lbs (2 086
kg) 8,100 lbs (3 674
kg) 32 Sq. Ft.
(2.97 square meters) 3,500 lbs (1 587
kg) 350 lbs (159
kg)
Refer to local laws for maximum trailer towing speeds.
Note 1 – The trailer tongue weight must be considered as
part of the combined weight of occupants and cargo, and
should never exceed the weight referenced on the Tire
and Loading Information placard. Refer to the Tire–
Safety Information Section in this manual.
Trailer and Tongue Weight
Always load a trailer with 60% to 65% of the weight in
the front of the trailer. This places 10% to 15% of the
Gross Trailer Weight (GTW) on the tow hitch of your
vehicle. Loads balanced over the wheels or heavier in the
rear can cause the trailer to sway severelyside to side
240 STARTING AND OPERATING

Towing Requirements
To promote proper break-in of your new vehicle drivetrain
components the following guidelines are recommended:
NOTE: Trailer towing requires special rear axle lubri-
cant. Refer to “Fluids, Lubricants, and Genuine Parts” in
Section 7 for more information.
CAUTION!
•Avoid towing a trailer for the first 500 miles (805
km) of vehicle operation. Doing so may damage
your vehicle.
•During the first 500 miles (805 km) of trailer
towing, limit your speed to 50 mph (80 km/h).
Perform the maintenance listed in Section 8 of this
manual. When towing a trailer, never exceed the GAWR,
or GCWR, ratings.
WARNING!
Improper towing can lead to an injury accident.
Follow these guidelines to make your trailer towing
as safe as possible:
Make certain that the load is secured in the trailer
and will not shift during travel. When trailering
cargo that is not fully secured, dynamic load shifts
can occur that may be difficult for the driver to
control. You could lose control of your vehicle and
have an accident.
•When hauling cargo or towing a trailer, do not over-
load your vehicle or trailer. Overloading can cause a
loss of control, poor performance or damage to brakes,
axle, engine, transmission, steering, suspension, chas-
sis structure or tires.
242 STARTING AND OPERATING

If using a manual transmission vehicle for trailer towing,
all starts must be in FIRST gear to avoid excessive clutch
slippage.
Towing Tips — Automatic Transmission
The “D” range can be selected when towing. However, if
frequent shifting occurs while in this range, the “3” range
should be selected.
NOTE: Using the “3” range while operating the vehicle
under heavy operating conditions will improve perfor-
mance and extend transmission life by reducing exces-
sive shifting and heat build up. This action will also
provide better engine braking.
The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See “Schedule B” in
section 8 of this manual for transmission fluid change
intervals. NOTE:
Check the automatic transmission fluid level
before towing.
Towing Tips — O/D Off (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the “O/D OFF” feature ON when driving in
hilly areas or shift the transmission to Drive position 2 on
more severe grades. Refer to “Transmission Shifting” in
this section.
Towing Tips — Electronic Speed Control (If
Equipped)

Don’t use in hilly terrain or with heavy loads.
When using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
Use speed control in flat terrain and with light loads to
maximize fuel efficiency.
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Towing Tips — Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
City Driving
When stopped for short periods of time, put transmission
in neutral and increase engine idle speed.
Highway Driving
Reduce speed.
Air Conditioning
Turn off temporarily.
refer to Cooling System Operating information in the
Maintenance section of this manual for more informa-
tion.
RECREATIONAL TOWING (BEHIND
MOTORHOME, ETC.)
CAUTION!
Front or rear wheel lifts should not be used. Internal
damage to the transmission or transfer case will
occur if a front or rear wheel lift is used when
recreational towing.
NOTE: The transfer case must be shifted into N (Neu-
tral) for recreational towing.
Shifting Into Neutral (N)
Use the following procedure to prepare your vehicle for
recreational towing.
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CAUTION!
It is necessary to follow these steps to be certain that
the transfer case is fully in N (Neutral) before
recreational towing to prevent damage to internal
parts.
1. Depress brake pedal.
2. Shift automatic transmission into N (Neutral) or de-
press clutch pedal on manual transmission.
3. Shift transfer case lever into N (Neutral).
4. Start engine.
5. Shift automatic transmission into D (Drive) or manual
transmission into gear.
6. Release brake pedal and ensure that there is no vehicle
movement. 7. Shut the engine off and place the ignition key into the
unlocked OFF position.
8. Shift automatic transmission into P (Park).
9. Apply parking brake.
10. Attach vehicle to the tow vehicle with tow bar.
11. Release parking brake.
CAUTION!
Damage to the transmission may occur if the trans-
mission is shifted into P (Park) with the transfer case
in N (Neutral) and the engine running. With the
transfer case in N (Neutral) ensure that the engine is
off prior to shifting the transmission into P (Park)
(refer to step s7–8
above).
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