1988 JEEP CHEROKEE spark plugs replace
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than .010" (.25 mm) from tip. Chamfer sharp edge of reground valve
tip. Recheck valve stem installed height.
VALVE STEM OIL SEALS
Valve stem oil seals must be installed on valve stem. See
Fig. 2 . Seals are needed due to pressure differential at the ends of
valve guides. Atmospheric pressure above intake guide, combined with
manifold vacuum below guide, causes oil to be drawn into the cylinder.
Exhaust guides also have pressure differential created by
exhaust gas flowing past the guide, creating a low pressure area. This
low pressure area draws oil into the exhaust system.
Replacement (On Vehicle)
Mark rocker arm or overhead cam components for location.
Remove rocker arm components or overhead cam components. Components
must be installed in original location. Remove spark plugs. Valve stem
oil seals may be replaced by holding valves against seats using air
pressure.
Air pressure must be installed in cylinder using an adapter
for spark plug hole. An adapter can be constructed by welding air hose
connection to spark plug body with porcelain removed.
Install adapter in spark plug hole. Apply a minimum of 140
psi (9.8 kg/cm
) to adapter. Air pressure should hold valve closed. If
air pressure does not hold valve closed, check for damaged or bent
valve. Cylinder head must be removed for service.
Using valve spring compressor, compress valve springs. Remove
valve locks. Carefully release spring compressor. Remove retainer or
rotator and valve spring. Remove valve stem oil seal.
If oversized valves have been installed, oversized oil seals
must be used. Coat valve stem with engine oil. Install protective
sleeve over end of valve stem. Install new oil seal over valve stem
and seat on valve guide. Remove protective sleeve. Install spring
seat, valve spring and retainer or rotator. Compress spring and
install valve locks. Remove spring compressor. Ensure valve locks
are fully seated.
Install rocker arms or overhead cam components. Tighten all
bolts to specification. Adjust valves if required. Remove adapter.
Install spark plugs, valve cover and gasket.
VALVE SPRING INSTALLED HEIGHT
Valve spring installed height should be checked during
reassembly. Measure height from lower edge of valve spring to the
upper edge. DO NOT include valve spring seat or retainer. Distance
must be within specifications. If valves and/or seats have been
ground, a valve spring shim may be required to correct spring height.
See Fig. 12 .
Fig. 12: Measuring Valve Spring Installed Height - Typical
This Graphic For General Information Only
Page 739 of 1378
Idle Speed Control Actuator ............................... ISC
Mix Control Solenoid .............................. MC Solenoid
Secondary Air Injection System Management Device .... AIR, PAIR
Vacuum Regulator Solenoid .................................. ..
Waste Gate Control Solenoid ................................ ..
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SHROUDS, BAFFLES AND DEFLECTORS
SHROUD, BAFFLE AND DEFLECTOR INSPECTION \
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Condition Code Procedure
Application incorrect,
affecting cooling system
performance ............ A . Require repair or replacement.
Attaching hardware
broken ................. A .. Require repair or replacement
of hardware.
Attaching hardware
missing ................ C ......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A .. Require repair or replacement
of hardware.
Bent, affecting cooling
system performance ..... A . Require repair or replacement.
Blocked, affecting cooling
system performance ..... A . Require repair or replacement.
Broken, affecting cooling
system performance ..... A . Require repair or replacement.
Cracked, affecting cooling
system performance ..... A . Require repair or replacement.
Loose, affecting cooling
system performance ..... A ................ Require repair.
Loose, not affecting
cooling system
performance ............ 2 ................ Suggest repair.
Missing, affecting cooling
system performance ..... C ........... Require replacement.
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SPARK PLUGS
NOTE: You are not required to replace spark plugs in sets.
However, you may suggest replacement of the other plugs
for preventive maintenance.
SPARK PLUG INSPECTION
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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Electrode eroded ........ 1 ............ Suggest replacement.
Fouled .................. A ........... ( 1) Require repair or
replacement.
Gap incorrect ........... B .. Require repair or replacement.
Insulation broken ....... A ............. Require replacement
Insulator cracked ....... A ............ Require replacement.
Leaking compression ..... A .. Require repair or replacement.
Maintenance interval .... 3 ............ Suggest replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
Page 865 of 1378
SPARK PLUG CHECK
Faulty or fouled plugs may perform well at idle speed, but at
higher engine speeds, they frequently fail. Faulty plug can exhibit
the following symptoms:
* Poor fuel economy.
* Power loss.
* Decreased engine speed.
* Hard starting.
* Generally poor performance.
Spark plugs also malfunction due to carbon fouling,
excessive electrode air gap, or broken insulators.
SYNC PULSE SIGNAL GENERATOR (STATOR) TEST
NOTE: For this test, an analog voltmeter MUST be used.
1) Insert the positive (+) lead of the voltmeter into the
Blue wire at the distributor connector.
2) Insert the negative (-) voltmeter lead into the Gray/Whit\
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wire at the distributor connector.
CAUTION: DO NOT remove the distributor connector from distributor.
Insert the voltmeter leads into the backside of the
distributor connector to make contact with the terminals.
3) Set the voltmeter to the 15-Volt D/C scale. Turn ignition
key to "ON".
4) The voltmeter should display approximately 5.0 volts.
5) If no voltage displays, check that the voltmeter leads are
making good contact. If there is still no voltage, go to next step.
6) Remove the ECU and check for voltage at pin "C-16" and
ground with harness connected. If there in still no voltage, proceed
to the next step.
7) Connect Diagnostic Tester M.S. 1700 to the vehicle. Using
the diagnostic tester, perform vehicle test. If voltage is present, go
to the next step.
8) Check for continuity between the Blue wire at the
distributor connector and pin C-16 at the ECU.
9) If there in no continuity, repair harness as necessary.
10) Check for continuity between the Gray/White wire at the
distributor connector and pin C-5 at the ECU.
11) If there is no continuity, repair harness as necessary.
12) Check for continuity between the Black wire at the
distributor connector and ground.
13) If there is no continuity, repair harness as necessary.
14) While observing the voltmeter, crank the engine; the
voltmeter needle should fluctuate back and forth while the engine in
cranking. A fluctuation verifies that the stator in the distributor is
operating properly.
15) If there is no pulse sync, replace the stator. Refer to
REMOVAL & INSTALLATION below in this article.
REMOVAL & INSTALLATION
COOLANT TEMPERATURE SENSOR (CTS)
Removal
1) Drain the cooling system.
Page 877 of 1378
Removal & Installation
Using care, disconnect the spark plug and coil wire boots and
wires. Twist the boot one half turn and pull on the boot to disconnect
the wire.
When replacing the spark plug and coil wires, carefully route
the wires correctly and secure them in their proper channels
retainers.
Failure to route the wires properly can cause the radio to
reproduce ignition noise, cross ignition of the plugs, or can short
circuit the wires to ground.
OVERHAUL
STATOR REPLACEMENT
Disassembly
1) Remove the distributor as specified in DISTRIBUTOR under
REMOVAL & INSTALLATION above in this article.
2) Remove the distributor rotor.
3) Position the distributor in a vise.
4) Remove the distributor gear from the shaft using a small
punch and a hammer to drive out the retaining roll pin. See Fig. 29.
5) Remove the distributor shaft from the distributor housing.
6) Remove the stator retaining screw.
NOTE: Mark the location of the stator position for reassembly
reference.
Fig. 29: Removing Distributor Gear Retaining Roll Pin
Courtesy of Chrysler Motors.
7) Remove stator harness by pushing the grommet through the
distributor housing. Remove stator assembly. See Fig. 30.
Page 957 of 1378
Fig. 5: Identification Label Locations
Courtesy of American Motors Corp.
SPARK PLUG REPLACEMENT INTERVALS
Spark plug replacement intervals, if given, are for Original
Equipment Manufacturer (OEM) installed or specified plugs. If vehicle
is equipped with platinum type or other non-OEM type spark plugs,
follow replacement interval specified by spark plug manufacturer.
OXYGEN SENSOR
If vehicle is equipped with an oxygen sensor, replace at 82,
500 miles or when the emissions maintenance reminder light remains on
continuously with the key in the ON position, whichever occurs first.
SEVERE & NORMAL SERVICE DEFINITIONS
CAUTION: Use the Severe Service schedule if the vehicle to be serviced
is operated under ANY (one or more) of these conditions:
Service is recommended at mileage intervals based on vehicle
operation. Normal Service and Severe Service are based on the
following primary operating conditions:
Severe Service
* Short Trips (About 15 Miles)
* Desert Or Cold Climate Operation
* Towing Or Heavily Loaded
* Severe Dust Conditions
* Hot Weather, Stop-And-Go Driving
Page 969 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual Lube Front Axle Drive Joint and Pivot Bearings (4WD)
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Lube Front Axle Drive Joint and Pivot Bearings (4WD)
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Suspension Bushings, Springs, Arms & Rear Jounce Bumpers
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Parking Brake System
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Lubricate Body Components
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Inspect Shocks for Leakage
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Inspect Tire Wear Pattern
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Rotate Tires and Adjust Air Pressure (Including Spare)
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Replace
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Engine Oil
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Oil Filter
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Spark Plugs
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Air Filter Element
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PCV Filter
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Fuel Filter
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Lubrication Specifications
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Application Specification
Automatic Transmission .......................... Dexron-IIE ATF
Brake Master Cylinder .......... DOT 3 (SAE J-1703F) Brake Fluid
Engine Coolant ........... Alugard 340-2 & Water (50/50 Mixture)
Engine Oil (
1)
Gasoline Engine
Temperature Range
Above 30
F (-1
C) ........ SAE 20W-40 Or 20W-50 API SH/CD
Above 0
F (-18
C) ......... SAE 10W-30 Or 10W-40 API SH/CD
Less Than 60
F (16
C) ............... SAE 5W-30 API SH/CD
Drive Axles ................................ SAE 75W-90 API GL-5
Drive Axles (Trac-Lok) (
2) ................ SAE 80W-140 API GL-5
Drive Axles (Trailer Towing) .............. SAE 80W-140 API GL-5
Hydraulic Clutch ............... DOT 3 (SAE J-1703F) Brake Fluid
Manual Transmission ........................ SAE 75W-90 API GL-5
Parking Brake Cable Guides ................. NLGI Grade 2, GC-LB
Door & Hood Hinges ............................ Light Engine Oil
Manual Steering Box ............... Multi-Purpose NLGI Grade 2EP
Power Steering Pump ....................... Power Steering Fluid
Transfer Case ................................... Dexron-IIE ATF
Brake Caliper Bushings ........ GE 661 or DOW 111 Silicone Grease
Caliper Slide Pins ........... GE 661 or DOW 111 Silicone Grease
Wheel Bearings .................. Multi-Purpose NLGI Grade GC-LB
Drive Shaft U-Joints .............. Multi-Purpose NLGI Grade 2EP
Steering Linkage (
4)( 5) .................... NLGI Grade 2, GC-LB
Ball Joints (
4)( 6) ......................... NLGI Grade 2, GC-LB
Weatherstrip .......................... Silicone Spray Lubricant
Wheel Lug Nut Torque ...................... 95 ft. lbs. (129 N.m)
(
1) - SAE 10W-30 SH/CD is preferred.
(
2) - Add 4 ozs. (118 ml) of Limited-Slip differential lubricant
additive when changing fluid.
Page 979 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual Choke Linkage
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Choke Linkage
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Ignition Timing
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Lubricate Manifold Heat Control Valve (if equipped)
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Clean PCV Breather (if equipped)
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Clean EGR Passages (if equipped)
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Inspect C/V Joint boots (4WD)
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Inspect Underside of Vehicle (Bolts & Threaded Fasteners)
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Check/Lube Manual Steering Gear
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Check Drive Shaft Seals
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Lubricate Ball Joints, Steering Linkage & Suspension
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Lube Drive Shaft U-Joints and Slip Splines
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Lube Front Axle Drive Joint and Pivot Bearings (4WD)
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Inspect Front Wheel Bearings (4WD)
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Suspension Bushings, Springs, Arms & Rear Jounce Bumpers
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Parking Brake System
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Inspect Tire Wear Pattern
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Rotate Tires and Adjust Air Pressure (Including Spare)
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Replace
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Engine Oil
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Oil Filter
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Ignition Cables
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Distributor Cap and Rotor
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Air Filter Element
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EGR Valve & Tube (1987-92)
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Automatic Transmission Fluid, Filter and Adjust Bands
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Accessory Drive Belts
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Lube Parking Brake Ratio Lever Pivot
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Lube Manual Gearshift Control (4WD Transfer Case)
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Inspect/Repack Front Wheel Bearings (2WD Models)
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Inspect Front Brake Pads & Rotors
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Lubricate Caliper Slide Rails
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Inspect Rear Brake Linings & Drums
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Inspect Brake System Hoses & Lines
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Inspect Shocks for Leakage
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Inspect Tire Wear Pattern
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Lubricate Weatherstripping with Silicone
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Lubricate Door Hinges
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Lubricate Door Locks
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Check Body Drain Holes
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Rotate Tires and Adjust Air Pressure
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Replace
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Engine Oil
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Oil Filter
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Air Filter Element
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Fuel Filter
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Spark Plugs
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Automatic Transmission Fluid, Filter and Adjust Bands
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PCV Filter
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PCV Valve (
1) ( 2)
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Drive Belt (V-Type) (
2) ( 3)
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(
1) - Replacement is recommended by Chrysler at this time, but it
is not required to maintain the warranty on the PCV valve.
(
2) - Not required, if belt or PCV Valve was previously replaced
(
3) - Check and replace as needed.
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Lubrication Specifications
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Application Specification
Automatic Transmission .......................... Dexron-IIE ATF
Brake Master Cylinder .......... DOT 3 (SAE J-1703F) Brake Fluid
Engine Coolant ........... Alugard 340-2 & Water (50/50 Mixture)
Engine Oil (
1)
Gasoline Engine
Temperature Range