1995 JEEP XJ sensor

(29) Disconnect the exhaust pipe from the mani-
fold.
(30) Disconnect the engine speed sensor wire con-
nection.
(31) Remove the exhaust pipe support.
(32) Remove the flywheel and converter housing
access cover.
(33)Vehicles with Automatic Transmission:
(a) Mark the converter and drive plate location.
(b) Remove the converter-to-drive plate bolts.
(34) Remove the upper flywheel and converter
housing bolts and loosen the bottom bolts.
(35) Remove the engine mount cushion-to-engine
compartment bracket bolts.
(36) Lower the vehicle.
(37) Attach a lifting device to the engine.
(38) Raise the engine off the front supports.
(39) Place a support or floor jack under the con-
verter (or flywheel) housing.
(40) Remove the remaining converter (or flywheel)
housing bolts.
(41) Lift the engine out of the engine compart-
ment.
INSTALLATION
CAUTION: When installing the engine into a vehicle
equipped with an automatic transmission, be care-
ful not to damage the trigger wheel on the flywheel.
(1) Attach a lifting device to the engine and lower
the engine into the engine compartment. For easier
installation, it may be necessary to remove the en-
gine mount cushions from the engine mount bracket
as an aide in alignment of the engine to the trans-
mission.
(2)Vehicles with Manual Transmission:
(a) Insert the transmission shaft into the clutch
spline.
(b) Align the flywheel housing with the engine.(c) Install and tighten the flywheel housing lower
bolts finger tight.
(3)Vehicles with Automatic Transmission:
(a) Align the transmission torque converter hous-
ing with the engine.
(b) Loosely install the converter housing lower
bolts and install the next higher bolt and nut on
each side.
(c) Tighten all 4 bolts finger tight.
(4) Install the engine mount cushions (if removed).
(5) Lower the engine and engine mount cushions
onto the engine compartment brackets. Install the
bolts and finger tighten the nuts.
(6) Remove the engine lifting device.
(7) Raise and support the vehicle.
(8) Install the remaining flywheel and converter
housing bolts. Tighten all bolts to 38 Nzm (28 ft. lbs.)
torque.
(9)Vehicles with Automatic Transmission:
(a) Install the converter-to-drive plate bolts.
(b) Ensure the installation reference marks are
aligned.
(10) Install the flywheel and converter housing ac-
cess cover.
(11) Install the exhaust pipe support and tighten
the screw.
(12) Tighten the engine mount-to-bracket bolts.
(13) Connect the engine speed sensor wire connec-
tions and tighten the screws.
(14) Connect the exhaust pipe to the manifold.
(15) Install the starter motor and connect the ca-
ble.
(16) Connect the wires to the starter motor sole-
noid.
(17) Lower the vehicle.
(18) Connect all the vacuum hoses and wire con-
nectors identified during engine removal.
(19) If equipped with power steering:
(a) Remove the protective caps
(b) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 Nzm (38 ft. lbs.)
torque.
(c) Fill the pump reservoir with fluid.
(20) Install the power brake vacuum check valve to
the booster, if equipped.
(21) Connect the fuel inlet and return hoses at the
fuel rail. Verify that the quick-connect fitting assem-
bly fits securely over the fuel lines by giving the fuel
lines a firm tug.
(22) Install the fuel line bracket to the intake man-
ifold.
(23) Connect the distributor electrical connector
and oil pressure switch connector.
(24) Connect the injection system wire harness
connector on the dash panel.
(25) Connect the line pressure cable (if equipped
with automatic transmission).
Fig. 16 Air Cleaner Assembly & Power Steering
Pump
J4.0L ENGINE 9 - 61

(18) Disconnect the oxygen sensor wire connector.
(19) Remove the upper radiator hose and coolant
recovery hose (Fig. 19).
(20) Disconnect lower radiator hoses at the radia-
tor.
(21) Disconnect the coolant hoses from the rear of
the intake manifold and thermostat housing.
(22) Remove the fan shroud screws.
(23) Remove the radiator attaching bolts.
(24) Remove the radiator and fan shroud (Fig. 19).
Refer to Group 7, Cooling System for the proper pro-
cedure.
(25) Remove the fan and spacer or Tempatrol fan
assembly.
(26) Install a 5/16 X 1/2-inch SAE capscrew
through fan pulley into water pump flange. This will
maintain the pulley and water pump in alignment
when crankshaft is rotated.
(27) Remove the power brake vacuum check valve
from the booster, if equipped.
(28) If equipped with power steering (Fig. 19):
(a) Disconnect the hoses from the fittings at the
steering gear.
(b) Drain the pump reservoir.
(c) Cap the fittings on the hoses and steering
gear to prevent foreign objects from entering the
system.
(29) Lift the vehicle and support it with support
stands.
(30) Remove the starter motor.
(31) Remove the flywheel housing access cover.
(32) Remove the engine support cushion-to-bracket
through bolts.
(33) Disconnect the exhaust pipe from the mani-
fold.
(34) Remove the upper flywheel housing bolts and
loosen the bottom bolts.
(35) Lower the vehicle.
(36) Attach a lifting device to the engine.(37) Raise the engine off the front supports.
(38) Place a support stand under the flywheel
housing.
(39) Remove the remaining flywheel housing bolts.
(40) Lift the engine out of the engine compartment
and install on an engine stand.
INSTALLATION
(1) Lift the engine off the stand and lower it into
the engine compartment. For easier installation, it
may be useful to remove the engine support cushions
from the engine support brackets as an aide for
alignment of the engine-to-transmission.
(2) Insert the transmission shaft into the clutch
spline.
(3) Align the flywheel housing with the engine.
(4) Install and finger tighten the flywheel housing
lower bolts.
(5) Install the engine support cushions (if re-
moved).
(6) Remove the support stand from beneath the
flywheel housing.
(7) Lower the engine and engine support cushions
onto the engine compartment brackets. Ensure that
the bolt holes are aligned. Install the bolts and
tighten the nuts.
(8) Remove the engine lifting device.
(9) Raise the vehicle.
(10) Attach the exhaust pipe to the manifold. In-
stall and tighten the nuts to 31 Nzm (23 ft. lbs.)
torque.
(11) Install the flywheel housing access cover.
(12) Install the remaining flywheel housing bolts.
Tighten the bolts to 38 Nzm (28 ft. lbs.) torque.
(13) Install the starter motor and connect the ca-
ble. Tighten the bolts to 45 Nzm (33 ft. lbs.) torque.
(14) Lower the vehicle.
(15) Connect the coolant hoses and tighten the
clamps.
Fig. 18 Fuel Line Quick-Connect Couplings, Air
Cleaner Assembly, Throttle & Speed Control CablesFig. 19 Upper Radiator Hose, Coolant Recovery
Hose, Fan Shroud & Power Steering Pump
J4.0L ENGINE 9 - 63

(16) Remove the pulley-to-water pump flange
alignment capscrew and install the fan and spacer or
Tempatrol fan assembly.
(17) Tighten the serpentine drive belt according to
the specifications listed in Group 7, Cooling System.
(18) Install the fan shroud and radiator (refer to
Group 7, Cooling System for the proper procedure).
(19) Connect the radiator hoses.
(20) Connect the throttle valve rod and retainer.
(21) Connect the throttle cable and install the rod.
(22) Install the throttle valve rod spring.
(23) Connect the speed control cable, if equipped.
(24) Connect the oxygen sensor wire connector.
(25) Install the vacuum hose and check valve on
the brake booster.
(26) Connect the coolant temperature sensor wire
connector.
(27) Connect the idle speed actuator wire connec-
tor.
(28) Connect the fuel inlet and return hoses at the
fuel rail. Verify that the quick-connect fitting assem-
bly fits securely over the fuel lines by giving the fuel
lines a firm tug.
(29) Install the fuel line bracket to the intake man-
ifold.
(30) Connect all fuel injection wire connections.
(31) Install the engine ground strap.
(32) Connect the ignition coil wire connector.
(33) Remove the coolant temperature sending unit
to permit air to escape from the block. Fill the cool-
ing system with coolant. Install the coolant tempera-
ture sending unit when the system is filled.
(34) If equipped with power steering:
(a) Remove the protective caps
(b) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 Nzm (38 ft. lbs.)
torque.
(c) Fill the pump reservoir with fluid.
(35) Install the battery and connect the battery ca-
bles.
(36) Install the air cleaner bonnet to the throttle
body.
(37) Install the air cleaner.
(38) Lower the hood and secure in place.
(39) Start the engine and inspect for leaks.
(40) Stop the engine and check the fluid levels.
Add fluid, as required.
ENGINE CYLINDER HEAD COVER
A cured gasket is part of the engine cylinder head
cover.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Disconnect the Crankcase Ventilation (CCV)
vacuum hose from engine cylinder head cover (Fig.
1).(3) Disconnect the fresh air inlet hose from the en-
gine cylinder head cover (Fig. 1).
(4) Remove the engine cylinder head cover mount-
ing bolts.
(5) Remove the engine cylinder head cover.
CLEANING
Remove any original sealer from the cover sealing
surface of the engine cylinder head and clean the
surface using a fabric cleaner.
Remove all residue from the sealing surface using
a clean, dry cloth.
INSPECTION
Inspect the engine cylinder head cover for cracks.
Replace the cover, if cracked.
The original dark grey gasket material should NOT
be removed. If sections of the gasket material are
missing or are compressed, replace the engine cylin-
der head cover. However, sections with minor damage
such as small cracks, cuts or chips may be repaired
with a hand held applicator. The new material must
be smoothed over to maintain gasket height. Allow
the gasket material to cure prior to engine cylinder
head cover installation.
INSTALLATION
(1) If a replacement cover is installed, transfer the
CCV valve grommet and oil filler cap from the origi-
nal cover to the replacement cover.
(2) Install engine cylinder head cover. Tighten the
mounting bolts to 13 Nzm (115 in. lbs.) torque.
(3) Connect the CCV hoses (Fig. 1).
(4) Connect negative cable to battery.
Fig. 1 Engine Cylinder Head Cover
9 - 64 4.0L ENGINEJ

(12) Place Timing Case Cover Alignment and Seal
Installation Tool 6139 in the crankshaft opening in
the cover (Fig. 12).
(13) Install the timing case cover-to-cylinder block
bolts. Install the oil pan-to-timing case cover bolts.
(14) Tighten the 1/4 inch cover-to-block bolts to 7
Nzm (60 in. lbs.) torque. Tighten the 5/16 inch front
cover-to-block bolts to 22 Nzm (192 in. lbs.) torque.
Tighten the oil pan-to-cover 1/4 inch bolts to 14 Nzm
(120 in. lbs.) torque. Tighten the oil pan-to-cover 5/16
inch bolts to 18 Nzm (156 in. lbs.) torque.
(15) Remove the cover alignment tool and install a
replacement oil seal into the cover.(16) Install the vibration damper on the crank-
shaft.
(17) Lubricate and tighten the damper bolt to 108
Nzm (80 ft. lbs.) torque.
(18) If equipped with air conditioning:
(a) Install the A/C compressor serpentine drive
belt idler pulley.
(b) Install the generator.
(c) Install the A/C condenser and receiver/drier
assembly.
(19) Install the serpentine drive belt on the pulleys
and tighten (refer to Group 7, Cooling System for the
specifications and procedures).
(20) Install the radiator. Connect the radiator
hoses and automatic transmission fluid cooler pipes,
if equipped. Fill the cooling system.
(21) Install the fan and shroud.
(22) Connect negative cable to battery.
OIL PAN
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Remove the oil pan drain plug and drain the
engine oil.
(4) Disconnect the exhaust pipe at the exhaust
manifold.
(5) Disconnect the exhaust hanger at the catalytic
converter and lower the pipe.
(6) Remove the starter motor.
(7) Remove the engine flywheel and transmission
torque converter housing access cover.
(8) If equipped with an oil level sensor, disconnect
the sensor.
(9) Position a jack stand directly under the engine
vibration damper.
(10) Place a piece of wood (2 x 2) between the jack
stand and the engine vibration damper.
(11) Remove the engine mount through bolts.
(12) Using the jack stand, raise the engine until
adequate clearance is obtained to remove the oil pan.
(13) Remove the oil pan bolts. Carefully slide the
oil pan and gasket to the rear. If equipped with an oil
level sensor, take care not to damage the sensor.
CLEANING
Clean the block and pan gasket surfaces.
INSTALLATION
(1) Fabricate 4 alignment dowels from 1/4 x 1 1/2
inch bolts. Cut the head off the bolts and cut a slot
into the top of the dowel. This will allow easier in-
stallation and removal with a screwdriver (Fig. 1).
(2) Install two dowels in the timing case cover. In-
stall the other two dowels in the cylinder block (Fig.
2).
Fig. 11 Verify CrankshaftÐCamshaft InstallationÐ
Typical
Fig. 12 Timing Case Cover Alignment and Seal
Installation Tool 6139
J4.0L ENGINE 9 - 77

(3) Slide the one-piece gasket over the dowels and
onto the block and timing case cover.
(4) Position the oil pan over the dowels and onto
the gasket. If equipped with an oil level sensor, take
care not to damage the sensor.
(5) Install the 1/4 inch oil pan bolts. Tighten these
bolts to 14 Nzm (120 in. lbs.) torque. Install the 5/16
inch oil pan bolts (Fig. 3). Tighten these bolts to 18
Nzm (156 in. lbs.) torque.
(6) Remove the dowels. Install the remaining 1/4
inch oil pan bolts. Tighten these bolts to 14 Nzm (120
in. lbs.) torque.(7) Lower the engine until it is properly located on
the engine mounts.
(8) Install the through bolts and tighten the nuts.
(9) Lower the jack stand and remove the piece of
wood.
(10) Install the engine flywheel and transmission
torque converter housing access cover.
(11) Install the engine starter motor.
(12) Connect the exhaust pipe to the hanger and to
the gine exhaust manifold.
(13) Install the oil pan drain plug (Fig. 3). Tighten
the plug to 34 Nzm (25 ft. lbs.) torque.
(14) Lower the vehicle.
(15) Connect negative cable to battery.
(16) Fill the oil pan with engine oil to the specified
level.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(18) Start the engine and inspect for leaks.
Fig. 1 Fabrication of Alignment Dowels
Fig. 2 Position of Dowels in Cylinder Block
Fig. 3 Position of 5/16 inch Oil Pan Bolts
9 - 78 4.0L ENGINEJ

EXHAUST SYSTEM AND INTAKE MANIFOLD
CONTENTS
page page
EXHAUST SYSTEM....................... 1
EXHAUST SYSTEM DIAGNOSIS............. 2SERVICE PROCEDURES................... 3
TORQUE SPECIFICATIONS................ 10
EXHAUST SYSTEM
GENERAL INFORMATION
The basic exhaust system consists of an engine ex-
haust manifold, exhaust pipe with oxygen sensor, cat-
alytic converter, exhaust heat shield(s), muffler and
exhaust tailpipe (Fig. 1).
The exhaust system uses a single muffler with a
single monolithic-type catalytic converter.
The 4.0L engines use a seal between the engine ex-
haust manifold and exhaust pipe to assure a tight
seal and strain free connections.
The exhaust system must be properly aligned to
prevent stress, leakage and body contact. If the sys-
tem contacts any body panel, it may amplify objec-tionable noises originating from the engine or body.
When inspecting an exhaust system, critically in-
spect for cracked or loose joints, stripped screw or
bolt threads, corrosion damage and worn, cracked or
broken hangers. Replace all components that are
badly corroded or damaged. DO NOT attempt to re-
pair.
When replacement is required, use original equip-
ment parts (or their equivalent). This will assure
proper alignment and provide acceptable exhaust
noise levels.
CAUTION: Avoid application of rust prevention com-
pounds or undercoating materials to exhaust sys-
tem floor pan exhaust heat shields. Light overspray
near the edges is permitted. Application of coating
will result in excessive floor pan temperatures and
objectionable fumes.
CATALYTIC CONVERTER
The stainless steel catalytic converter body is de-
signed to last the life of the vehicle. Excessive heat
can result in bulging or other distortion, but exces-
sive heat will not be the fault of the converter. If un-
burned fuel enters the converter, overheating may
occur. If a converter is heat-damaged, correct the
cause of the damage at the same time the converter
is replaced. Also, inspect all other components of the
exhaust system for heat damage.
Unleaded gasoline must be used to avoid contami-
nating the catalyst core.
EXHAUST HEAT SHIELDS
Exhaust heat shields are needed to protect both the
vehicle and the environment from the high tempera-
tures developed by the catalytic converter. The cata-
lytic converter releases additional heat into the
exhaust system. Under severe operating conditions,
the temperature increases in the area of the con-
Fig. 1 Typical Exhaust System
JEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 1

SERVICE PROCEDURES
INDEX
page page
Catalytic Converter......................... 4
Engine Exhaust ManifoldÐ2.5L Engine.......... 7
Engine Exhaust ManifoldÐ4.0L Engine.......... 7
Exhaust PipeÐXJ Vehicles................... 3
Exhaust PipeÐYJ Vehicles................... 4Intake ManifoldÐ2.5L Engine................. 7
Intake ManifoldÐ4.0L Engine................. 8
Muffler and Exhaust TailpipeÐXJ Vehicles........ 5
Muffler and Exhaust TailpipeÐYJ Vehicles........ 6
EXHAUST PIPEÐXJ VEHICLES
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
REMOVAL
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with heat valve lu-
bricant (Fig. 1). Allow 5 minutes for penetration.
(3) Remove the oxygen sensor from the exhaust
pipe (Fig. 2).
(4) Disconnect the exhaust pipe from the engine
exhaust manifold. Discard the seal (4.0L engine,
only).(5) Support the transmission and remove the rear
crossmember.
(6) Remove the clamp nuts and clamp (Fig. 3). To
remove the exhaust pipe from the catalytic converter,
apply heat until the metal becomes cherry red. Dis-
connect the exhaust pipe from the catalytic converter
(Fig. 3). Remove the exhaust pipe.
Fig. 1 Exhaust Pipe-to-Engine Exhaust Manifold
Nuts
Fig. 2 Oxygen Sensor
Fig. 3 Exhaust Pipe-to-Catalytic Converter
Connection
JEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 3

INSTALLATION
(1) Assemble exhaust pipe to manifold and cata-
lytic converter loosely to permit proper alignment of
all parts.
(2) Use a new clamp and tighten the nuts to 61
Nzm (45 ft. lbs.) torque.
(3) Connect the exhaust pipe to the engine exhaust
manifold. Install a new seal between the exhaust
manifold and the exhaust pipe (4.0L engine, only).
Tighten the nuts to 31 Nzm (23 ft. lbs.) torque (Fig.
1).
(3) Install the rear crossmember. Tighten the
crossmember-to-sill bolts to 41 Nzm (30 ft. lbs.)
torque. Remove the support from the transmission.
(4) Coat the oxygen sensor with anti-seize com-
pound. Install the sensor and tighten the nut to 48
Nzm (35 ft. lbs.) torque.
(5) Lower the vehicle.
(6) Start the engine and inspect for exhaust leaks
and exhaust system contact with the body panels.
Adjust the alignment, if needed.
EXHAUST PIPEÐYJ VEHICLES
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
REMOVAL
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with heat valve lu-
bricant (Fig. 4). Allow 5 minutes for penetration.(3) Remove the oxygen sensor from the exhaust
pipe (Fig. 2).
(4) Disconnect the exhaust pipe from the engine
exhaust manifold.
(5) Disconnect the exhaust pipe from the catalytic
converter and slide the pipe out of the transmission
torque arm insulator (Fig. 5). Remove the exhaust
pipe.
INSTALLATION
(1) Slide the exhaust pipe into the transmission
torque arm insulator and onto the catalytic converter
(Fig. 5).
(2) Clean the mating surface of the engine exhaust
manifold flange.
(3) Connect the exhaust pipe to the engine exhaust
manifold using new nuts. DO NOT tighten the nuts.
(4) Align the exhaust pipe.
(5) Use a new clamp at the exhaust pipe to cata-
lytic converter connection and tighten the nuts to 61
Nzm (45 ft. lbs.) torque.
(6) Tighten the exhaust pipe-to-engine exhaust
manifold nuts to 31 Nzm (23 ft. lbs.) torque.
(7) Coat the oxygen sensor with anti-seize com-
pound. Install the sensor and tighten the nut to 48
Nzm (35 ft. lbs.) torque.
(8) Lower the vehicle.
(9) Start the engine and inspect for exhaust leaks
and exhaust system contact with the body panels.
Adjust the alignment, if needed.
CATALYTIC CONVERTER
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
REMOVAL
(1) Raise and support the vehicle.
Fig. 4 Exhaust Pipe-to-Engine Exhaust Manifold
Bolts and Nuts
Fig. 5 Exhaust Pipe-to-Catalytic Converter
ConnectionÐYJ Vehicles
11 - 4 EXHAUST SYSTEM AND INTAKE MANIFOLDJ