1995 JEEP YJ fuel

(14) Install the remaining flywheel housing bolts.
Tighten the bolts to 38 Nzm (28 ft. lbs.) torque.
(15) Install the starter motor and connect the ca-
ble. Tighten the bolts to 45 Nzm (33 ft. lbs.) torque.
(16) Install the oil filter.
(17) Lower the vehicle.
(18) Connect the coolant hoses and tighten the
clamps.
(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) Remove the pulley-to-water pump flange
alignment capscrew and install the fan and spacer or
Tempatrol fan assembly.
(21) Tighten the serpentine drive belt according to
the specifications listed in Group 7, Cooling System.
(22) Install the fan shroud and radiator.
(23) Connect the radiator hoses.
(24) Connect the heater hoses.
(25) Connect the throttle valve rod and retainer.
(26) Connect the throttle cable and install the rod.
(27) Install the throttle valve rod spring.
(28) Connect the speed control cable, if equipped.
(29) Connect the oxygen sensor wire connector.
(30) Install the vacuum hose and check valve on
the brake booster.
(31) Connect the coolant temperature sensor wire
connector.
(32) Connect the idle speed actuator wire connec-
tor.
(33) 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.
(34) Install the fuel line bracket to the intake man-
ifold.
(35) Connect all fuel injection wire connections.
(36) Install the engine ground strap.
(37) Connect the ignition coil wire connector.
(38) 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.
(39) Install the battery and connect the battery ca-
bles.
(40) Install the air cleaner bonnet to the throttle
body.
(41) Install the air cleaner.
(42) Lower the hood and secure in place.
(43) Start the engine and inspect for leaks.
(44) 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 the oil filler cap from the origi-
nal cover to the replacement cover.
(2) Install engine cylinder head cover. Tighten the
mounting bolts to 10 Nzm (85 in. lbs.) torque.
Fig. 1 Engine Cylinder Head Cover
9 - 22 2.5L ENGINEJ

(9) If equipped, disconnect the power steering
pump bracket. Set the pump and bracket aside. DO
NOT disconnect the hoses.
(10) Remove the fuel lines and vacuum advance
hose.
(11) Remove the intake and engine exhaust mani-
folds from the engine cylinder head (refer to Group
11, Exhaust System and Intake Manifold for the
proper procedures).
(12) Disconnect the ignition wires and remove the
spark plugs.
(13) Disconnect the temperature sending unit wire
connector.
(14) Remove the ignition coil and bracket assem-
bly.
(15) Remove the engine cylinder head bolts.
(16) Remove the engine cylinder head and gasket
(Fig. 3).
(17) If this was the first time the bolts were re-
moved, put a paint dab on the top of the bolt. If the
bolts have a paint dab on the top of the bolt or it
isn't known if they were used before, discard the
bolts.
(18) Stuff clean lint free shop towels into the cylin-
der bores.
CLEANING
Thoroughly clean the engine cylinder head and cyl-
inder block mating surfaces. Clean the intake and ex-
haust manifold and engine cylinder head mating
surfaces. Remove all gasket material and carbon.
Check to ensure that no coolant or foreign material
has fallen into the tappet bore area.
Remove the carbon deposits from the combustion
chambers and top of the pistons.
INSPECTION
Use a straightedge and feeler gauge to check the
flatness of the engine cylinder head and block mating
surfaces.
INSTALLATION
The engine cylinder head gasket is a composition
gasket. The gasket is to be installed DRY.DO NOT
use a gasket sealing compound on the gasket.
If the engine cylinder head is to be replaced and
the original valves used, measure the valve stem di-
ameter. Only standard size valves can be used with a
service replacement engine cylinder head unless the
replacement head valve stem guide bores are reamed
to accommodate oversize valve stems. Remove all
carbon buildup and reface the valves.
(1) Fabricate two engine cylinder head alignment
dowels from used head bolts (Fig. 4). Use the longest
head bolt. Cut the head of the bolt off below the hex
head. Then cut a slot in the top of the dowel to allow
easier removal with a screwdriver.
(2) Install one dowel in bolt hole No.10 and the
other dowel in bolt hole No.8 (Fig. 5).
(3) Remove the shop towels from the cylinder
bores. Coat the bores with clean engine oil.
(4) Place the engine cylinder head gasket (with the
numbers facing up) over the dowels.
(5) Place the engine cylinder head over the dowels.
Fig. 3 Engine Cylinder Head Assembly
Fig. 4 Fabricate Alignment Dowels
Fig. 5 Alignment Dowel Locations
9 - 26 2.5L ENGINEJ

CAUTION: Engine cylinder head bolts should be re-
used only once. Replace the head bolts if they were
used before or if they have a paint dab on the top
of the bolt.
(6) Coat the threads of bolt No.7, only, with Loctite
PST sealant or equivalent.
(7) Install all head bolts, except No.8 and No.10.
(8) Remove the dowels.
(9) Install No.8 and No.10 head bolts.
(10) Tighten the engine cylinder head bolts in se-
quence according to the following procedure (Fig. 6):
(a) Tighten all bolts in sequence (1 through 10)
to 30 Nzm (22 ft. lbs.) torque.
(b) Tighten all bolts in sequence (1 through 10)
to 61 Nzm (45 ft. lbs.) torque.
(c) Check all bolts to verify they are set to 61
Nzm (45 ft. lbs.) torque.
(d) Tighten bolts (in sequence):
²Bolts 1 through 6 to 149 Nzm (110 ft. lbs.) torque.
²Bolt 7 to 136 Nzm (100 ft. lbs.) torque.
²Bolts 8 through 10 to 149 Nzm (110 ft. lbs.) torque.
CAUTION: During the final tightening sequence,
bolt No.7 will be tightened to a lower torque than
the rest of the bolts. DO NOT overtighten bolt No.7.
(e) Check all bolts in sequence to verify the cor-
rect torque.
(f) If not already done, clean and mark each bolt
with a dab of paint after tightening. Should you en-
counter bolts which were painted in an earlier ser-
vice operation, replace them.
(11) Install the ignition coil and bracket assembly.
(12) Connect the temperature sending unit wire
connector.
(13) Install the spark plugs and tighten to 37 Nzm
(27 ft. lbs.) torque. Connect the ignition wires.
(14) Install the intake and exhaust manifolds (re-
fer to Group 11, Exhaust System and Intake Mani-
fold for the proper procedures).(15) Install the fuel lines and the vacuum advance
hose.
(16) If equipped, attach the power steering pump
and bracket.
(17) Install the push rods, rocker arms, pivots and
bridges in the order they were removed.
(18) Install the engine cylinder head cover.
(19) Attach the air conditioning compressor mount-
ing bracket to the engine cylinder head and block.
Tighten the bolts to 40 Nzm (30 ft. lbs.) torque.
(20) Attach the air conditioning compressor to the
bracket. Tighten the bolts to 27 Nzm (20 ft. lbs.)
torque.
CAUTION: The serpentine drive belt must be routed
correctly. Incorrect routing can cause the water
pump to turn in the opposite direction causing the
engine to overheat.
(21) Install the serpentine drive belt and correctly
tension the belt (refer to Group 7, Cooling System for
the proper procedure).
(22) Install the air cleaner and ducting.
(23) Install the engine cylinder head cover.
(24) Connect the hoses to the thermostat housing
and fill the cooling system to the specified level (refer
to Group 7, Cooling Systems for the proper proce-
dure).
(25) The automatic transmission throttle linkage
and cable must be adjusted after completing the en-
gine cylinder head installation (refer to Group 21,
Transmissions for the proper procedures).
(26) Install the temperature sending unit and con-
nect the wire connector.
(27) Connect the fuel pipe and vacuum advance
hose.
(28) Connect negative cable to battery.
(29) Connect the upper radiator hose and heater
hose at the thermostat housing.
(30) Fill the cooling system. Check for leaks.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN DIRECT
LINE WITH THE FAN. DO NOT PUT HANDS NEAR
THE PULLEYS, BELTS OR FAN. DO NOT WEAR
LOOSE CLOTHING.
(31) Operate the engine with the radiator cap off.
Inspect for leaks and continue operating the engine
until the thermostat opens. Add coolant, if required.
VALVES AND VALVE SPRINGS
This procedure is done with the engine cylinder
head removed from the block.
REMOVAL
(1) Remove the engine cylinder head from the cyl-
inder block.
Fig. 6 Engine cylinder head Bolt Tightening
Sequence
J2.5L ENGINE 9 - 27

4.0L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 74
Camshaft Pin Replacement.................. 75
Engine AssemblyÐXJ Vehicles............... 59
Engine AssemblyÐYJ Vehicles............... 62
Engine Cylinder Head...................... 67
Engine Cylinder Head Cover................. 64
Engine MountÐRear....................... 57
Engine MountsÐFront..................... 56
General Information....................... 55
Hydraulic Tappets......................... 66
OilPan ................................. 77Rocker Arms and Push Rods................ 65
Timing Case Cover........................ 72
Timing Case Cover Oil Seal Replacement....... 73
Timing Chain and Sprockets................. 73
Valve Component ReplaceÐCylinder Head Not
Removed.............................. 65
Valve Stem Seal and Spring Replacement....... 65
Valve Timing............................. 71
Valves and Valve Springs................... 69
Vibration Damper......................... 72
GENERAL INFORMATION
The 4.0 Liter (242 CID) six-cylinder engine is an
In-line, lightweight, overhead valve engine (Fig. 1).
This engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in good
fuel economy.
The cylinders are numbered 1 through 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 2).
The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. The camshaft rotates
within four bearings.
BUILD DATE CODE
The engine Build Date Code is located on a ma-
chined surface on the right side of the cylinder block
between the No.2 and No.3 cylinders (Fig. 3).
Fig. 1 Engine Description
Fig. 2 Engine Firing Order
Fig. 3 Build Date Code Location
J4.0L ENGINE 9 - 55

The digits of the code identify:
(1) 1st DigitÐThe year (4 = 1994).
(2) 2nd & 3rd DigitsÐThe month (01 - 12).
(3) 4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel in-
jection system).
(4) 6th & 7th DigitsÐThe day of engine build (01 -
31).
FOR EXAMPLE:Code * 401MX12 * identifies a
4.0 Liter (242 CID) engine with a multi-point fuel in-
jection system, 8.7:1 compression ratio and built on
January 12, 1994.
OVERSIZE AND UNDERSIZE COMPONENT
CODES
Some engines may be built with oversize or under-
size components such as:
²Oversize cylinder bores.
²Oversize camshaft bearing bores.
²Undersize crankshaft main bearing journals.
²Undersize connecting rod journals.
These engines are identified by a letter code (Fig.
4) stamped on a boss between the ignition coil and
the distributor (Fig. 5).
ENGINE MOUNTSÐFRONT
The front mounts support the engine at each side.
These supports are made of resilient rubber.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Support the engine.
(4) Remove the nut from the through bolt (Figs. 6
and 7). DO NOT remove the through bolt.
(5) Remove the retaining bolts and nuts from the
support cushions (Figs. 6 and 7).
(6) Remove the through bolt.
(7) Remove the support cushions.
INSTALLATION
(1) If the engine support bracket was removed, po-
sition the bracket onto the block and install the at-
taching bolts (Figs. 6 and 7). Tighten the engine
support bracket bolts:
²XJ VehiclesÐ61 Nzm (45 ft. lbs.) torque.
²YJ VehiclesÐ62 Nzm (46 ft. lbs.) torque.
(2) ON XJ VEHICLES, if the support cushion
bracket was removed, position the bracket onto the
lower front sill (Fig. 8). Install support cushion
bracket bolts and nuts. Tighten the bolts to 54 Nzm
(40 ft. lbs.) torque. Tighten the nuts to 41 Nzm (30 ft.
lbs.) torque.
(3) Place the support cushion into position on the
support cushion bracket (Figs. 6 and 7). Install and
tighten the bolts and nuts:
²XJ VehiclesÐ41 Nzm (30 ft. lbs.) torque.
²YJ VehiclesÐ52 Nzm (38 ft. lbs.) torque.
(4) Install the through bolt and the retaining nut
(Figs. 6 and 7). Tighten the through bolt nut:
²XJ VehiclesÐ65 Nzm (48 ft. lbs.) torque.
²YJ VehiclesÐ69 Nzm (51 ft. lbs.) torque.
Fig. 4 Oversize and Undersize Component Codes
Fig. 5 Oversize and Undersize Component Code
Location
9 - 56 4.0L ENGINEJ

(6) Remove upper radiator support retaining bolts
and remove radiator support.
(7) Remove the fan shroud (Fig. 13) and electric
cooling fan.
(8) Disconnect the transmission fluid cooler tubing
(automatic transmission).
(9) Disconnect radiator fan switch wire connector.
(10)Vehicles with Air Conditioning:
(a) Discharge the A/C condenser.
(b) Remove the service valves and cap the com-
pressor ports.
(11) Remove the radiator or radiator and con-
denser (if equipped with A/C).
(12) Remove the fan assembly from the idler pul-
ley.
(13) Disconnect the heater hoses at the engine
thermostat housing and water pump (Figs. 13 and
14).
(14) Disconnect the throttle linkages (Fig. 15).
(15) Disconnect the speed control cable (if
equipped)Ð(Fig. 15).(16) Disconnect the line pressure cable (if equipped
with automatic transmission).
(17) Disconnect injection system wire harness con-
nector at the dash panel.
(18) Disconnect the distributor electrical connec-
tion and the oil pressure switch connector.
(19) Perform the Fuel System Pressure Release
procedure (refer to Group 14, Fuel System).
(20) Disconnect the quick-connect fuel lines at the
fuel rail and return line by squeezing the two retain-
ing tabs against the fuel tube (Fig. 15). Pull the fuel
tube and retainer from the quick-connect fitting (re-
fer to Group 14, Fuel System for the proper proce-
dure).
(21) Remove the fuel line bracket from the intake
manifold.
(22) Remove the air cleaner assembly (Fig. 16).
(23) Remove the power brake vacuum check valve
from the booster, if equipped.
(24) If equipped with power steering (Fig. 16):
(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.
(25) Identify, tag and disconnect all necessary wire
connectors and vacuum hoses.
(26) Raise and support the vehicle.
(27) Disconnect the wires from the starter motor
solenoid.
(28) Remove the starter motor.
Fig. 13 Upper Radiator Hose, Coolant Recovery
Hose, Fan Shroud & Heater hoses
Fig. 14 Heater Hoses (RH Drive Vehicle)
Fig. 15 Accelerator Cable, Speed Control Cable,
Automatic Transmission Control Cable & Quick-
Connect Fuel Lines
9 - 60 4.0L ENGINEJ

(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

(26) Connect the speed control cable, if equipped.
(27) Connect the throttle cable linkages.
(28) Connect the heater hoses at the engine ther-
mostat housing and water pump.
(29) Install the fan assembly to the idler pulley.
(30) Install the radiator or radiator and condenser
(if equipped with A/C).
(31) Connect the service valves to the A/C compres-
sor ports, if equipped with A/C.
(32) Charge the air conditioner system.
(33) Connect radiator fan switch wire.
(34) Connect automatic transmission fluid cooler
lines, if equipped.
(35) Install the fan shroud, electric cooling fan and
radiator and condenser (if equipped with A/C).
(36) Install upper radiator support.
(37) Connect the upper radiator hose.
(38) Connect the lower radiator hose.
(39) Fill the cooling system with reusable coolant
and/or new coolant.
(40) Align the hood to the scribe marks. Install the
hood.
(41) Connect the vacuum harness connector.
(a) Firmly push the connectors together ensuring
that the retaining tabs are engaged.
(b) Insert the vacuum connector assembly into
the retaining bracket on the intake manifold.
(42) Install the air cleaner assembly.
(43) Install the battery and connect the battery ca-
ble.
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.
(44) Start the engine, inspect for leaks and correct
the fluid levels, as necessary.
ENGINE ASSEMBLYÐYJ VEHICLES
REMOVAL
(1) Place a protective cloth over the windshield
frame. Raise the hood and rest it on the windshield
frame (Fig. 17).
(2) Disconnect the battery cables. Remove the bat-
tery.
WARNING: THE COOLANT IN A RECENTLY OPERATED
ENGINE IS HOT AND PRESSURIZED. USE CARE TO
PREVENT SCALDING BY HOT COOLANT. CAREFULLY
RELEASE THE PRESSURE BEFORE REMOVING THE
RADIATOR DRAIN COCK AND CAP.
(3) Remove the radiator drain cock and radiator
cap to drain the coolant. DO NOT waste reusablecoolant. If the solution is clean, drain the coolant into
a clean container for reuse.
(4) Disconnect the wire connectors from the gener-
ator.
(5) Disconnect the ignition coil and distributor wire
connectors.
(6) Disconnect the oil pressure sender wire connec-
tor.
(7) Disconnect the wires at the starter motor sole-
noid and injection wire harness connector.
(8) Perform the Fuel System Pressure Release pro-
cedure (refer to Group 14, Fuel System).
(9) Disconnect the quick-connect fuel lines at the
fuel rail and return line by squeezing the retaining
tabs against the fuel tube (Fig. 18). Pull the fuel tube
and retainer from the quick-connect fitting (refer to
Group 14, Fuel System for the proper procedure).
(10) Remove the fuel line bracket from the intake
manifold.
(11) Disconnect the engine ground strap.
(12) Remove the air cleaner (Fig. 18).
(13) Disconnect the vacuum purge hose at the fuel
vapor canister tee.
(14) Disconnect the idle speed actuator wire con-
nector.
(15) Disconnect the throttle cable and remove it
from the bracket (Fig. 18).
(16) Disconnect the throttle rod at the bellcrank.
(17) Disconnect the speed control cable, if equipped
(Fig. 18).
Fig. 17 Hood on Windshield Frame
9 - 62 4.0L ENGINEJ