clock JEEP XJ 1995 Service And Owner's Guide

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

LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 5).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Leak-Down
Tester.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch) di-
ameter ball bearing on the plunger cap of the tappet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal po-
sition.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require 20-
110 seconds to leak-down. Discard tappets with leak-
down time interval not within this specification.
INSTALLATION
It is not necessary to charge the tappets with en-
gine oil. They will charge themselves within a very
short period of engine operation.(1) Dip each tappet in Mopar Engine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool C-4129-A to install each tappet in the same
bore from where it was originally removed.
(3) Install the push rods in their original locations.
(4) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(5) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 Nzm (21 ft. lbs.) torque.
(6) Pour the remaining Mopar Engine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The Mopar Engine Oil Supplement, or
equivalent must remain with the engine oil for at
least 1 609 km (1,000 miles). The oil supplement
need not be drained until the next scheduled oil
change.
(7) Install the engine cylinder head cover.
ENGINE CYLINDER HEAD
This procedure can be done with the engine in or
out of the vehicle.
REMOVAL
(1) Disconnect negative cable from battery.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAIN COCK WITH THE SYSTEM HOT AND PRES-
SURIZED BECAUSE SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
(2) Drain the coolant and disconnect the hoses at
the engine thermostat housing. DO NOT waste reus-
able coolant. If the solution is clean and is being
drained only to service the engine or cooling system,
drain the coolant into a clean container for reuse.
(3) Remove the air cleaner assembly.
(4) Remove the engine cylinder head cover.
(5) Remove the capscrews, bridge and pivot assem-
blies and rocker arms (Fig. 2).
(6) Remove the push rods (Fig. 2).Retain the
push rods, bridges, pivots and rocker arms in
the same order as removed.
(7) Loosen the serpentine drive belt at the power
steering pump, if equipped or at the idler pulley (re-
fer to Group 7, Cooling System for the proper proce-
dure).
(8) If equipped with air conditioning, perform the
following:
(a) Remove the bolts from the A/C compressor
mounting bracket and set the compressor aside.
(b) Remove the air conditioner compressor
bracket bolts from the engine cylinder head.
(c) Loosen the through bolt at the bottom of the
bracket.
Fig. 5 Leak-Down Tester
J4.0L ENGINE 9 - 67

ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
inch). If the measurement differs from specification
by more than 0.076 mm (0.003 inch), ream the guide
bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD:
(1) Use a dial indicator to measure the lateral
movement of the valve stem (stem-to-guide clear-
ance). This must be done with the valve installed in
its guide and just off the valve seat (Fig. 11).
(2) Correct clearance is 0.025-0.0762 mm (0.001-
0.003 inch). If indicated movement exceeds the spec-
ification ream the valve guide to accommodate an
oversize valve stem.
Valve seats must be ground after reaming the
valve guides to ensure that the valve seat is
concentric to the valve guide.
VALVE SPRING TENSION TEST
Use a universal Valve Spring Tester and a torque
wrench to test each valve spring for the specified ten-
sion value (Fig. 12).
Replace valve springs that are not within specifica-
tions.
INSTALLATION
(1) Thoroughly clean the valve stems and the valve
guide bores.
(2) Lightly lubricate the stem.
(3) Install the valve in the original valve guide
bore.
(4) Install the replacement valve stem oil seals on
the valve stems. If the 0.381 mm (0.015 inch) over-
size valve stems are used, oversize oil seals are re-
quired.(5) Position the valve spring and retainer on the
engine cylinder head and compress the valve spring
with Valve Spring Compressor Tool MD-998772A.
(6) Install the valve locks and release the tool.
(7) Tap the valve spring from side to side with a
hammer to ensure that the spring is properly seated
at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.6 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
Fig. 11 Measurement of Lateral Movement of Valve
Stem
Fig. 12 Valve Spring Tester
J4.0L ENGINE 9 - 71

FUEL DELIVERY SYSTEM
INDEX
page page
Fuel Filter................................ 9
Fuel Pressure Leak Down Test................ 8
Fuel Pressure Release Procedure.............. 6
Fuel Pump Capacity Test.................... 7
Fuel Pump Electrical Control.................. 5Fuel Pump Module......................... 3
Fuel System Pressure Test................... 6
Fuel Tubes/Lines/Hoses and Clamps............ 9
Quick-Connect Fittings..................... 10
FUEL PUMP MODULE
The fuel pump module is installed in the top of the
fuel tank. The fuel pump module contains the follow-
ing components:
²Electric fuel pump
²Fuel pump reservoir
²In-tank fuel filter
²Fuel gauge sending unit
²Fuel supply and return tube connections
The fuel pump used on all vehicles is a turbine
type pump. It is driven by a permanent magnet 12
volt electric motor that is immersed in the fuel tank.
The electrical pump is integral with the fuel sender
unit. The pump/sender assembly is installed inside
the fuel tank.
The fuel pump has a check valve at the outlet end
that consists of a ball held against a seat by force ap-
plied from a spring. When the pump is operating,
fuel pressure overcomes spring pressure and forces
the ball off its seat, allowing fuel to flow. When the
pump is not operating, spring pressure forces the ball
back against the seat preventing fuel backflow
through the pump.
Fuel system pressure is maintained at approxi-
mately 214 kPa (31 psi). This is when the pump is
operating and vacuum is supplied to the fuel pres-
sure regulator. If vacuum is not supplied to the pres-
sure regulator, fuel pressure will be approximately
55-69 kPa (8-10 psi) higher. This may be due to a
broken or clogged vacuum line. When the fuel pump
is not operating, fuel system pressure of 131-269 kPa
(19-39 psi) is maintained for approximately 2 to 6
hours. This is done by the fuel pump outlet check
valve and the vacuum assisted fuel pressure regula-
tor.
REMOVALÐXJ MODELS
The fuel pump/gauge sender unit assembly can be
removed from the fuel tank without removing the
tank from the vehicle.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE FUEL PUMP MODULE,
THE FUEL SYSTEM PRESSURE MUST BE RE-LEASED. REFER TO THE FUEL PRESSURE RE-
LEASE PROCEDURE IN THIS GROUP.
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Remove fuel filler cap. Perform the Fuel Pres-
sure Release Procedure as outlined in this group.
(2) Disconnect negative battery cable.
(3) Using an approved portable gasoline siphon/
storage tank, drain fuel tank until fuel level is below
one quarter (1/4) full.
(4) Raise and support vehicle.
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(5) Disconnect fuel vent supply and return tubes
from fittings on fuel pump module.
(6) Disconnect fuel pump module electrical harness
connector from main harness.
(7) Using a brass punch and hammer, remove fuel
pump module lock ring by carefully tapping it coun-
terclockwise (Fig. 1).
Fig. 1 Removing Lock RingÐXJ ModelsÐTypical
JFUEL DELIVERY SYSTEM 14 - 3

(8) Remove fuel pump module and O-ring seal.
Discard old O-ring and fuel pump module inlet filter.
DISASSEMBLYÐXJ MODELS
(1) Remove and discard fuel pump inlet filter.
The wire terminals to the fuel pump motor are dif-
ferent in size and cannot be connected to the wrong
terminal.
(2) Disconnect fuel pump terminal wires.
(3) Remove fuel pump outlet hose and clamp. Re-
place the hose if it shows any signs of fatigue or fail-
ure.
(4) Remove fuel pump top mounting bracket nut.
Remove fuel pump (Fig. 2).
ASSEMBLYÐXJ MODELS
Whenever the fuel pump is replaced, the fuel pump
inlet filter (sock) must also be replaced.
(1) Place fuel pump top mounting bracket over top
of pump.
(2) Position fuel pump into lower bracket. Slide
stud of top bracket through hole in fuel pump side
bracket. Tighten fuel pump top mounting nut.
(3) Install new fuel pump outlet hose. Secure with
new clamps.
(4) Connect wire terminals to motor.
(5) Install new fuel pump inlet filter.
INSTALLATIONÐXJ MODELS
Whenever the fuel pump is replaced, the fuel
pump inlet filter must also be replaced.
(1) Install new fuel pump inlet filter onto fuel
pump.(2) Install fuel pump module assembly and new O-
ring seal. The rubber stopper on the end of the fuel
return tube of the assembly must be inserted into the
cup in the fuel tank reservoir (Fig. 3).
(3) Using a brass punch and a hammer, install lock
ring. Carefully tap lock ring clockwise until it seats
against stop on fuel tank.
(4) Connect fuel supply and return hoses to fittings
on fuel pump module. Tighten hose clamps.
(5) Connect fuel pump module electrical harness
connector to main harness connector.
(6) Lower vehicle.
(7) Fill fuel tank. Install fuel tank cap.
(8) Connect negative battery cable.
(9) Start vehicle and inspect for leaks.
REMOVALÐYJ MODELS
The fuel tank must be removed to remove the fuel
pump module.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE FUEL PUMP MODULE,
THE FUEL SYSTEM PRESSURE MUST BE RE-
LEASED. REFER TO THE FUEL PRESSURE RE-
LEASE PROCEDURE IN THIS GROUP.
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Remove negative battery cable.
Fig. 2 Fuel Pump ModuleÐXJ ModelsÐ
Disassemble/Assemble
Fig. 3 Fuel Pump ModuleÐXJ ModelsÐInstallation
14 - 4 FUEL DELIVERY SYSTEMJ

²SECOND - over-center preload adjustment
WORM THRUST BEARING PRELOAD
ADJUSTMENT
(1) Remove adjuster plug locknut (Fig. 8).
(2) Turn the adjuster in with Spanner Wrench
C-4381. Tighten the plug and thrust bearing in the
housing until firmly bottomed in housing.
(3) Place an index mark on the housing even with
one of the holes in adjuster plug (Fig. 9).(4) Measure back (counterclockwise) 13 mm (0.50
in) and mark housing (Fig. 10).
(5) Rotate adjustment cap back (counterclockwise)
with spanner wrench until hole is aligned with the
second mark (Fig. 11).
(6) Install and tighten locknut to 109 Nzm (80 ft.
lbs.) torque. Be sure adjustment cap does not turn
while tightening the locknut.
OVER-CENTER ADJUSTMENT
(1) Rotate the stub shaft from stop to stop and
count the number of turns.
Fig. 10 Remarking The Housing
Fig. 11 Aligning To The Second Mark
Fig. 8 Loosening the Adjuster Plug Locknut
Fig. 9 Alignment Marking On Housing
JSTEERING 19 - 25

(2) Starting at either stop turn the stub shaft back
1/2 the total number of turns. This is the center of
the gear travel (Fig. 12).
(3) Turn the pitman shaft adjuster screw back
(COUNTERCLOCKWISE) until extended, then turn
back in (CLOCKWISE) one full turn.
(4) Place the torque wrench in the vertical position
on the stub shaft. Rotate the wrench 45 degrees each
side of the center and record the highest rotational
torque on center (Fig. 13).
(5) Turn the adjuster in until torque to turn stub
shaft is 0.6 to 1.2 Nzm (6.0 to 10.0 in. lbs.) more than
reading in Step 4.
(6) Prevent the adjuster screw from turning while
tightening adjuster lock nut. Tighten the adjuster
lock nut to 49 Nzm (36 ft. lbs.).
GEAR DISASSEMBLY INFORMATION
CAUTION: Cleanliness is extremely important when
repairing a power steering gear. Keep the bench,
tools and components clean at all times. Thor-
oughly clean the exterior of the gear with cleaning
solvent before disassembly. Drain as much of the
fluid as possible. Use protective vise jaws at all
times when clamping components. During assem-
bly, lubricate all components with power steering
fluid except where noted (Fig. 14).
Fig. 12 Steering Gear Centered
Fig. 13 Checking Over-center Rotation Torque
19 - 26 STEERINGJ

PITMAN SHAFT AND SIDE COVER REPLACEMENT
REMOVE
(1) Remove steering gear from vehicle. Refer to
Power Steering Gear Replacement in this section.
(2) Remove pitman arm from steering gear. Refer
to Pitman Arm Removal in the Steering Linkage sec-
tion.
(3) Rotate stub shaft back and forth to drain power
steering fluid.
DISASSEMBLE
²Clean exposed end of pitman shaft and housing.
²Clean pitman shaft spline with a wire brush.
(1) Remove preload adjuster nut.
(2) Rotate stub shaft with socket to center gear.
Remove side cover bolts.
(3) Remove side cover, gasket and pitman shaft as
an assembly.
(4) Remove pitman shaft from the side cover (Fig.
15).
ASSEMBLE
(1) Install pitman shaft to side cover by screwing
shaft in until it fully seats to side cover.
(2) Install preload adjuster nut.Do not tighten
nut until after pitman shaft adjustment has
been made.(3) Install gasket to side cover and bend tabs
around edges of side cover.
(4) Install pitman shaft assembly and side cover to
housing.
(5) Install side cover bolts and tighten to 60 Nzm
(44 ft. lbs.).
(6) Adjust pitman shaft, refer to Over-Center Ad-
justment.
INSTALL
(1) Install steering gear. Refer to Power Steering
Gear Replacement in this section.
(2) Install pitman arm onto steering gear. Refer to
Steering Linkage in this Group.
HOUSING END PLUG
REMOVE
(1) Remove steering gear from vehicle. Refer to
Power Steering Gear Replacement in this section.
(2) Remove pitman arm from steering gear. Refer
to Steering Linkage in this Group.
(3) Rotate stub shaft back and forth to drain power
steering fluid.
DISASSEMBLE
²Rotate stub shaft back and forth to drain fluid
(1) Rotate retaining ring until one end is under the
hole in the housing. Unseat and force ring from
groove (Fig. 16).
(2) Rotate stub shaft slowly COUNTER-CLOCK-
WISE to remove end plug out from housing (Fig. 17).
Fig. 15 Side Cover and Pitman Shaft
Fig. 16 End Plug Retaining Ring
19 - 28 STEERINGJ

(6) Lubricate O-ring seals and teflon rings with
power steering fluid.
(7) Install stub shaft and valve assembly to worm
shaft, fitting on worm shaft to slot in the valve as-
sembly.
(8) Adjust Thrust Bearing Preload Adjustment and
Over-Center Adjustment. Refer to Steering Gear Ad-
justments in this section.
INSTALL
(1) Install steering gear. Refer to Power Steering
Gear Replacement in this section.
RACK PISTON AND WORM SHAFT REPLACEMENT
REMOVE
(1) Remove steering gear from vehicle. Refer to
Power Steering Gear Replacement in this section.
DISASSEMBLE
(1) Remove pitman shaft and side cover. Refer to
Side Cover and Pitman Shaft Replacement in this
section.
(2) Remove housing plug end. Refer to Housing
End Plug Replacement in this section.
(3) Turn stub shaft COUNTERCLOCKWISE until
the rack piston begins to come out of the housing.
(4) Remove rack piston plug (Fig. 30).
(5) Insert Arbor C-4175 into bore of rack piston
(Fig. 31). Hold tool tightly against worm shaft while
turning the stub shaft COUNTERCLOCKWISE.
²The rack piston will be forced onto the tool and
hold the rack piston balls in place.
(6) Remove the rack piston, rack balls, and tool to-
gether from housing.
(7) Remove valve. Refer to Valve Replacement in
this section.
(8) Remove worm shaft.
(9) Remove thrust bearing and races.
(10) Remove tool from rack piston.
(11) Remove rack piston balls.
(12) Remove screws, clamp and ball guide.
(13) Remove teflon ring and O-ring seal (Fig. 32).
Fig. 28 Remove and Install Valve Seals
Fig. 29 Stub Shaft Installation
Fig. 30 Remove and Install Rack Piston End Plug
19 - 32 STEERINGJ

CLEAN AND INSPECTION
(1) Wash all components in clean solvent and dry
with compressed air.
(2) Check for scores, nicks or burrs on the rack pis-
ton finished surface. Slight wear is normal on the
worm gear surfaces.
ASSEMBLE
(1) Install O-ring seal and teflon ring and lubricate
with power steering fluid.
(2) Install worm shaft to rack piston outside of
housing. Fully seat worm shaft to rack piston and
align worm shaft spiral groove with rack piston ball
guide hole (Fig. 33).
WARNING: MAKE SURE ALL RACK PISTON BALLS
ARE REINSTALLED IN THE RACK PISTON. IM-
PROPER INSTALLATION MAY RESULT IN PER-
SONAL INJURY.There are 24 balls in the rack piston circuit,
12 are black and 12 are silver (Chrome). The
black rack piston balls are smaller than the sil-
ver balls. THE BLACK AND SILVER BALLS
MUST BE INSTALLED ALTERNATELY INTO
THE RACK PISTON AND BALL GUIDE. This
procedure will maintain worm shaft preload.
(3) Lubricate and install rack piston balls through
return guide hole while turning wormshaft COUN-
TERCLOCKWISE.
(4) Install remaining balls to guide using grease or
petroleum jelly at each end to hold in place (Fig. 34).
(5) Install guide onto rack piston and return with
clamp and screws. Tighten screws to 58 Nzm (43 in.
lbs.) torque.
(6) Insert Arbor C-4175 into bore of rack piston.
Hold tool tightly against worm shaft while turning
Fig. 31 Remove and Install Rack Piston
Fig. 32 Remove and Install Seal on Rack Piston
Fig. 33 Installing Balls in Rack Piston
Fig. 34 Balls in the Return Guide
JSTEERING 19 - 33