1995 JEEP XJ fuel type

The high-line cluster includes the following gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²speedometer/odometer
²tachometer
²trip odometer
²voltmeter.
The high-line cluster includes provisions for the fol-
lowing indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²four-wheel drive indicator lamps
²headlamp high beam indicator lamp
²low fuel warning lamp
²low washer fluid warning lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp
²turn signal indicator lamps
²upshift indicator lamp.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the in-
strument cluster gauge area printed circuit. With the
ignition switch in the OFF position, voltage is not
supplied to the gauges. A gauge pointer may remain
within the gauge scale after the ignition switch is
OFF. However, the gauges do not accurately indicate
any vehicle condition unless the ignition switch is
ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
The gauge needle moves as the movable permanent
magnet aligns itself to the changing magnetic fields
created around it by the electromagnets.
COOLANT TEMPERATURE GAUGE
The coolant temperature gauge gives an indication
of engine coolant temperature. The coolant tempera-
ture sending unit is a thermistor that changes elec-
trical resistance with changes in engine coolanttemperature. High sending unit resistance causes
low coolant temperature readings. Low resistance
causes high coolant temperature readings.
The gauge will read at the high end of the scale
when the ignition switch is turned to the START po-
sition. This is caused by the bulb test circuit wiring
provision. The same wiring is used for the high-line
cluster with a coolant temperature gauge and the
low-line cluster with a coolant temperature warning
lamp. Sending unit resistance values are shown in a
chart in Specifications.
FUEL GAUGE
The fuel gauge gives an indication of the level of
fuel in the fuel tank. The fuel gauge sending unit has
a float attached to a swing-arm in the fuel tank. The
float moves up or down within the fuel tank as fuel
level changes. As the float moves, an electrical con-
tact on the swing-arm wipes across a resistor coil,
which changes sending unit resistance. High sending
unit resistance causes low fuel level readings. Low
resistance causes high fuel level readings. Sending
unit resistance values are shown in a chart in Spec-
ifications.
OIL PRESSURE GAUGE
The oil pressure gauge gives an indication of en-
gine oil pressure. The combination oil pressure send-
ing unit contains a flexible diaphragm. The
diaphragm moves in response to changes in engine
oil pressure. As the diaphragm moves, sending unit
resistance increases or decreases. High resistance on
the gauge side of the sending unit causes high oil
pressure readings. Low resistance causes low oil
pressure readings. Sending unit resistance values are
shown in a chart in Specifications.
SPEEDOMETER/ODOMETER
The speedometer/odometer gives an indication of
vehicle speed and travel distance. The speedometer
receives a vehicle speed pulse signal from the Vehicle
Speed Sensor (VSS). An electronic integrated circuit
contained within the speedometer reads and analyzes
the pulse signal. It then adjusts the ground path re-
sistance of one electromagnet in the gauge to control
needle movement. It also sends signals to an electric
stepper motor to control movement of the odometer
number rolls. Frequency values for the pulse signal
are shown in a chart in Specifications.
The VSS is mounted to an adapter near the trans-
mission (two-wheel drive) or transfer case (four-wheel
drive) output shaft. The sensor is driven through the
adapter by a speedometer pinion gear. The adapter
and pinion vary with transmission, transfer case,
axle ratio and tire size. Refer to Group 21 - Trans-
mission and Transfer Case for more information.
8E - 2 INSTRUMENT PANEL AND GAUGESÐXJJ

INSTRUMENT PANEL AND GAUGESÐYJ
CONTENTS
page page
INSTRUMENT PANEL AND GAUGESÐYJ..... 22
DIAGNOSIS............................ 23
GENERAL INFORMATION................. 20SERVICE PROCEDURES.................. 31
SPECIFICATIONS........................ 39
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
and heater components can be accessed without com-
plete instrument panel removal.
Removal of the left instrument cluster bezel allows
access to the main cluster assembly and most
switches. Removal of the center cluster bezel allows
access to the gauge package cluster assembly, the
heater controls, and the radio. Removal of the cluster
assemblies allows access to the individual gauges, il-
lumination and indicator lamp bulbs, printed cir-
cuits, and most wiring.
INSTRUMENT CLUSTERS
The instrument cluster used on YJ (Wrangler) mod-
els consists of two separate assemblies. The main
cluster assembly is located on the left side of the in-
strument panel, centered over the steering column
opening. The gauge package cluster assembly is lo-
cated near the center of the instrument panel. Each
cluster assembly is served by a separate printed cir-
cuit and wiring connector. Some variations of each
cluster exist due to optional equipment and regula-
tory requirements.
The main cluster assembly includes a speedometer/
odometer/trip odometer and a tachometer. It also in-
cludes provisions for the following indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²headlamp high beam indicator lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp²turn signal indicator lamps
²upshift indicator lamp.
The gauge package cluster assembly includes a
four-wheel drive indicator lamp and the following
gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²voltmeter.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the
two cluster printed circuits. With the ignition switch
in the OFF position, voltage is not supplied to the
gauges. A gauge pointer may remain within the
gauge scale after the ignition switch is OFF. How-
ever, the gauges do not accurately indicate any vehi-
cle condition unless the ignition switch is ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
8E - 24 INSTRUMENT PANEL AND GAUGESÐYJJ

minutes). The use of a locating dowel is recom-
mended during assembly to prevent smearing the
material off location.
Mopar Gasket Maker should be applied sparingly
to one gasket surface. The sealant diameter should
be 1.00 mm (0.04 inch) or less. Be certain the mate-
rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo-
cating dowel is recommended during assembly to pre-
vent smearing the material off location.
ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label found
on the engine compartment hood.
(1) Test battery specific gravity. Add water, if nec-
essary. Clean and tighten battery connections.
(2) Test cranking amperage draw (refer to Group
8B, Battery/Starter Service for the proper proce-
dures).
(3) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications).
(4) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces-
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature.
(c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times.
The higher engine speed may help clean out valve
seat deposits which can prevent accurate compres-
sion readings.
CAUTION: DO NOT overspeed the engine.
(d) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for ab-
normal firing indicatorsÐfouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start-
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check.
(g) Insert compression gage adaptor into the
No.1 spark plug hole. Crank engine until maximum
pressure is reached on gauge. Record this pressure
as No.1 cylinder pressure.
(h) Repeat Step 4g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.(j) If cylinder(s) have abnormally low compres-
sion pressures, repeat steps 4a through 4h.
(k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should NOT be disassem-
bled to determine the cause of low compression
unless some malfunction is present.
(5) Clean or replace spark plugs as necessary. Ad-
just gap (refer to Group 8D, Ignition System for gap
adjustment and torque).
(6) Test resistance of spark plug cables (refer to
Group 8D, Ignition System).
(7) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(8) Perform a combustion analysis.
(9) Test fuel pump for pressure (refer to Group 14,
Fuel System for the proper specifications).
(10) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce-
dure).
(11) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(12) For emission controls refer to Group 25, Emis-
sion Controls System for service procedures.
(13) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust-
ments).
(14) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels un-
der the bores and over the crankshaft to keep abra-
sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de-
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from ma-
jor oil distributors.
9 - 2 ENGINESJ

2.5L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 32
Camshaft Pin Replacement.................. 34
Engine AssemblyÐXJ Vehicles............... 18
Engine AssemblyÐYJ Vehicles............... 20
Engine Cylinder Head...................... 25
Engine Cylinder Head Cover................. 22
Engine Damper........................... 17
Engine MountÐRear....................... 16
Engine MountsÐFront..................... 14
General Information....................... 13
Hydraulic Tappets......................... 24OilPan ................................. 36
Rocker Arms and Push Rods................ 23
Timing Case Cover........................ 31
Timing Case Cover Oil Seal Replacement....... 30
Timing Chain and Sprockets................. 31
Valve Component ReplaceÐCylinder Head Not
Removed.............................. 23
Valve Springs and Oil Seals................. 23
Valve Timing............................. 30
Valves and Valve Springs................... 27
Vibration Damper......................... 30
GENERAL INFORMATION
The 2.5 liter (150 CID) four-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 4 from front
to rear. The firing order is 1-3-4-2 (Fig. 2).
The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within five main bearings and 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.3 and No.4 cylinders (Fig. 3).
Fig. 1 Engine Description
Fig. 2 Engine Firing Order
Fig. 3 Build Date Code Location
J2.5L ENGINE 9 - 13

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 (HX = A 2.5 liter (150 CID) 9.1:1
compression ratio engine with a multi-point fuel in-
jection system).
(4) 6th & 7th DigitsÐThe day of engine build (01 -
31).
FOR EXAMPLE:Code * 401HX23 * identifies a
2.5 liter (150 CID) engine with a multi-point fuel in-
jection system, 9.1:1 compression ratio and built on
January 23, 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 the oil filter boss near the distributor
(Fig. 5).
ENGINE MOUNTSÐFRONT
The front mounts support the engine at each side.
These supports are made of resilient rubber.
REMOVALÐXJ VEHICLES
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Support the engine.
(4) Remove through bolt nut (Fig. 6). DO NOT re-
move the through bolt.
(5) Remove the retaining bolts and nuts from the
support cushions (Fig. 6).
(6) Remove the through bolt.
(7) Remove the support cushions.
INSTALLATIONÐXJ VEHICLES
(1) If the engine support bracket was removed, po-
sition the LEFT bracket (Fig. 6) and the RIGHT
bracket with generator brace (Fig. 7) onto the cylin-
der block. Install the bolts and stud nuts.
(a) RIGHT SIDE (Fig. 7)ÐTighten the bolts to 61
Nzm (45 ft. lbs.) torque. Tighten the stud nuts to 46
Nzm (34 ft. lbs.) torque.
(b) LEFT SIDE (Fig. 6)ÐTighten the bolts to 61
Nzm (45 ft. lbs.) torque.
(2) If the support cushion brackets were removed,
position the brackets onto the lower front sill (Figs. 6
and 8). Install the bolts and stud nuts. Tighten the
bolts to 54 Nzm (40 ft. lbs.) torque and the stud nuts
to 41 Nzm (30 ft. lbs.) torque.
(3) Place the support cushions onto the support
cushion brackets (Fig. 6). Tighten the right support
cushion nuts to 65 Nzm (48 ft. lbs.) torque. Tighten
the left support cushion bolt and nut to 41 Nzm (30
ft. lbs.) torque.
Fig. 4 Oversize and Undersize Component Codes
Fig. 5 Oversize and Undersize Component Code
Location
9 - 14 2.5L ENGINEJ

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

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