1988 JEEP CHEROKEE lock

NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
CLEANING & INSPECTION
Clean camshaft with solvent. Ensure all oil passages are
clear. Inspect cam lobes and bearing journals for pitting, flaking or
scoring. Using micrometer, measure bearing journal O.D.
Support camshaft at each end with "V" blocks. Position dial
indicator with tip resting on center bearing journal. Rotate camshaft
and note reading. If reading exceeds specification, replace camshaft.
Check cam lobe lift by measuring base circle of camshaft
using micrometer. Measure again at 90 degrees to tip of cam lobe. Cam
lift can be determined by subtracting base circle diameter from tip of
cam lobe measurement.
Different lift dimensions are given for intake and exhaust
cam lobes. Reading must be within specifications. Replace camshaft if
cam lobes or bearing journals are not within specifications.
Inspect camshaft gear for chipped, eroded or damaged teeth.
Replace gear if damaged. On camshafts using thrust plate, measure
distance between thrust plate and camshaft shoulder. Replace thrust
plate if not within specification.
CAMSHAFT BEARINGS
Removal & Installation
Remove the camshaft rear plug. The camshaft bearing remover
is assembled with its shoulder resting on the bearing to be removed
according to manufacturer's instructions. Tighten puller nut until
bearing is removed. Remove remaining bearings, leaving front and rear
bearings until last. These bearings act as guide for camshaft bearing
remover.
To install new bearings, puller is rearranged to pull
bearings toward the center of block. Ensure all lubrication passages
of bearing are aligned with cylinder block. Coat new camshaft rear
plug with sealant. Install camshaft rear plug. Ensure plug is even
in cylinder block.
CAMSHAFT INSTALLATION
Lubricate bearing surfaces and cam lobes with ample amount of
Molykote or camshaft lubricant. Carefully install camshaft. Use care
not to damage bearing journals during installation. Install thrust
plate retaining bolts (if equipped). Tighten bolts to specification.
On overhead camshafts, install bearing caps in original location.
Tighten bolts to specification. Check end play.
CAMSHAFT END PLAY
Using dial indicator, check end play. Position dial indicator
on front of engine block. Position indicator tip against camshaft.
Push camshaft toward rear of engine and adjust indicator to zero.
Move camshaft forward and note reading. Camshaft end play
must be within specification. End play may be adjusted by relocating
gear, shimming thrust plate or replacing thrust plate depending on
manufacturer.
TIMING CHAINS & BELTS

* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
TIMING CHAINS
Timing chains will stretch during operation. Limits are
placed upon amount of stretch before replacement is required. Timing
chain stretch will alter ignition timing and valve timing.
To check timing chain stretch, rotate crankshaft to eliminate
slack from one side of timing chain. Mark reference point on cylinder
block. Rotate crankshaft in opposite direction to eliminate slack from
remaining side of timing chain. Force other side of chain outward
and measure distance between reference point and timing chain. See
Fig. 23 . Replace timing chain and gears if not within specification.
Fig. 23: Measuring Timing Chain Stretch - Typical
This Graphic For General Information Only
Timing chains must be installed so that timing marks on
camshaft gear and crankshaft gear are aligned according to

* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
TIMING GEAR BACKLASH & RUNOUT
On engines where camshaft gear operates directly on
crankshaft gear, gear backlash and runout must be checked. To check
backlash, install dial indicator with tip resting on tooth of camshaft
gear. Rotate camshaft gear as far as possible. Adjust indicator to
zero. Rotate camshaft gear in opposite direction as far as possible
and note reading.
To determine timing gear runout, mount dial indicator with
tip resting on face edge of camshaft gear. Adjust indicator to zero.
Rotate camshaft gear 360 degrees and note reading. If backlash or
runout exceed specifications, replace camshaft and/or crankshaft
gear.
REAR MAIN OIL SEAL
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
INSTALLATION
One-Piece Type Seal
For one-piece type oil seal installation, coat block contact
surface of seal with sealer if seal is not factory coated. Ensure seal
surface is free of burrs. Lubricate seal lip with engine oil and press
seal into place using proper oil seal installer. See Fig. 27.
Fig. 27: Installing Typical One-Piece Oil Seal
This Graphic For General Information Only
Rope Type Seal
For rope type rear main oil seal installation, press seal

lightly into its seat. Using seal installer, fully seat seal in
bearing cap or cylinder block.
Trim seal ends even with block parting surface. Some
applications require sealer to be applied on main bearing cap prior
to installation. See Fig. 28.
Fig. 28: Typical Rope Seal Installation
This Graphic For General Information Only
Split-Rubber Type Seal
Follow manufacturers procedures when installing split-rubber
type rear main oil seals. Installation procedures vary with engine
type. See appropriate ENGINE article in this section. See Fig. 29.
Fig. 29: Typical Split-Rubber Seal Installation
This Graphic For General Information Only
OIL PUMP

Engine pre-oiling can be done using pressure oiler (if
available). Connect pressure oiler to cylinder block oil passage
such as oil pressure sending unit. Operate pressure oiler long enough
to ensure correct amount of oil has filled crankcase. Check oil level
while pre-oiling.
If pressure oiler is not available, disconnect ignition
system. Remove oil pressure sending unit and replace with oil pressure
test gauge. Using starter motor, rotate engine starter until gauge
shows normal oil pressure for several seconds. DO NOT crank engine
for more than 30 seconds to avoid starter motor damage.
Ensure oil pressure has reached the most distant point from
the oil pump. Reinstall oil pressure sending unit. Reconnect ignition
system.
INITIAL START-UP
Start the engine and operate engine at low speed while
checking for coolant, fuel and oil leaks. Stop engine. Recheck coolant
and oil level. Adjust if necessary.
CAMSHAFT
Break-in procedure is required when a new or reground
camshaft has been installed. Operate and maintain engine speed between
1500-2500 RPM for approximately 30 minutes. Procedure may vary due to
manufacturers recommendations.
PISTON RINGS
Piston rings require a break-in procedure to ensure seating
of rings to cylinder walls. Serious damage may occur to rings if
correct procedures are not followed.
Extremely high piston ring temperatures are produced obtained
during break-in process. If rings are exposed to excessively high RPM
or high cylinder pressures, ring damage can occur. Follow piston ring
manufacturer's recommended break-in procedure.
FINAL ADJUSTMENTS
Check or adjust ignition timing and dwell (if applicable).
Adjust valves (if necessary). Adjust carburetion or injection idle
speed and mixture. Retighten cylinder heads (if required). If
cylinder head or block is aluminum, retighten bolts when engine is
cold. Follow the engine manufacturer's recommended break-in procedure
and maintenance schedule for new engines.
NOTE: Some manufacturer's require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.

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EN G IN E R EM OVA L - 4 -C YL

1988 J e ep C hero ke e
1988 ENGINES
Jeep - Engine Removal - 4-Cylinder
Cherokee, Comanche, Wrangler
4-CYLINDER ENGINES
2.5L
1) Disconnect negative battery cable. Drain cooling system.
Remove air cleaner, lower radiator hose, fan shroud, and engine
compartment light from hood. Scribe hinge locations and remove hood.
Disconnect automatic transmission cooler lines at radiator (if
equipped).
2) Remove upper radiator hose, fan assembly and coolant
recovery hose. Remove radiator and A/C condenser (if equipped). Hold
fan pulley to water pump flange using 5/16" x 1/2" SAE capscrew.
Disconnect heater hoses, throttle linkages, cruise control cable (if
equipped) and Throttle valve rod.
3) Disconnect wires from starter and separate CEC system
wiring harness connector. Disconnect fuel pipe from fuel pump and fuel
return hose from fuel filter. Disconnect hoses from A/C compressor and
power steering pump (if equipped). Drain power steering pump
reservoir. Cap all fittings and hose ends.
4) Remove vacuum check valve from brake booster (if
equipped). Tag and remove all wiring and vacuum lines connected to
engine or accessories. Raise vehicle and remove starter. Disconnect
exhaust pipe from manifold.
5) Remove converter/flywheel housing cover. Remove engine
mount nuts at bracket side. On automatic transmission models, index
mark drive plate and torque converter. Remove drive plate-to-converter
bolts.
6) Remove upper and loosen lower bellhousing-to-engine bolts.
Attach lifting equipment to engine. Raise engine off front mounts,
Place support under bellhousing. Remove remaining bellhousing-to-
engine bolts. Lift engine out of engine compartment.
NOTE: Engine mount pads may be removed from engine brackets to
align engine and transmission during installation.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Clutch Housing-to-Block Bolts .................... 55 (75)
Drive Plate-to-Converter ......................... 26 (35)
Flywheel Bolts ............................... ( 1) 50 (68)
Front Support Bracket-to-Block ................... 45 (61)
Front Support Cushion-to-Crossmember ............. 33 (45)
Rear Support Bracket-to-Transmission ............. 33 (45)
Rear Support Cushion-to-Bracket .................. 30 (41)
Starter Motor-to-Block ........................... 33 (45)
( 1) - Tighten an additional 60 degrees.









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transmission, remove converter housing cover. Index mark converter and
driven plate for reassembly. Remove driven plate-to-converter bolts,
rotating crankshaft to access each bolt. Remove oil pan bolts holding
automatic transmission oil lines. On Wrangler models, remove exhaust
pipe support brace at converter housing.
6) On manual transmission models, remove flywheel housing
cover. Remove inner support bolts for clutch release arm. Disconnect
springs and remove clutch release arm. Remove outer bracket retainer
for release lever rod. On all models, remove upper and loosen lower
bellhousing bolts.
7) Lower vehicle. Support transmission. If A/C equipped,
remove idler pulley and mounting bracket. Attach lifting equipment to
engine. Raise engine off front mounts and support transmission. Remove
lower bellhousing bolts. Lift engine from compartment while pulling
forward.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Automatic Transmission-to-Block .................. 28 (38)
Clutch Housing-to-Block
Top ............................................ 27 (37)
Bottom ......................................... 43 (58)
Drive Plate-to-Converter ......................... 22 (30)
Drive Plate/Flywheel-to-Crankshaft ............. 105 (143)
Front Support Bracket-to-Block ................... 35 (47)
Front Support Cushion-to-Bracket ................. 33 (45)
Front Support Cushion-to-Crossmember ............. 37 (50)
Rear Support Bracket-to-Transmission ............. 33 (45)
Rear Support Cushion-to-Bracket .................. 30 (41)
Starter Motor-to-Converter Housing ............... 18 (24)









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* E N G IN E S YSTE M S U NIF O RM IN SPEC TIO N G UID ELIN ES *

1 988 J e ep C hero ke e
GENERAL INFORMATION
Engine Performance and Maintenance Motorist Assurance Program
Standards For Automotive Repair
All Makes and Models
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
CONTENTS
Motorist Assurance Program (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
OVERVIEW OF SERVICE REQUIREMENTS AND SUGGESTIONS
Engine Assemblies
CYLINDER HEAD ASSEMBLIES
LONG BLOCK ASSEMBLIES
SHORT BLOCK ASSEMBLIES
Engine Components
ACCELERATOR PEDAL POSITION SENSORS
ACCESSORY BELTS
ACCESSORY PULLEYS
ACTUATORS
AIR CONDITIONING CYCLING SWITCHES
AIR CONDITIONING PRESSURE SENSORS
AIR DUCTS AND TUBES
AIR FILTER ELEMENTS
AIR FILTER GASKETS
AIR FILTER HOUSINGS AND GASKETS
AIR FUEL RATIO SENSORS
AIR INJECTION CONTROL SOLENOIDS
AIR PLENUMS
AIR PUMP BELTS
AIR PUMPS (ELECTRIC-DRIVEN)
AIR TUBES
ASPIRATOR, CHECK AND DECEL VALVES
BAFFLES
BALLAST PRIMARY SUPPLY RESISTOR WIRES
BALLAST RESISTORS AND PRIMARY SUPPLY RESISTOR WIRES
BAROMETRIC PRESSURE SENSORS
BATTERIES
BATTERY CABLES, WIRES AND CONNECTORS
BATTERY CONNECTORS
BATTERY TRAYS AND HOLD DOWN HARDWARE
BATTERY WIRES
BELT-DRIVEN AIR PUMPS
BELT IDLER ASSEMBLIES (ACCESSORY AND CAM BELTS)
BELT TENSIONERS (ACCESSORY AND CAM BELTS)
BOOST CONTROL MECHANISMS
CAMSHAFT POSITION SENSORS
CARBURETORS AND CHOKES
CASTING CORE PLUGS AND EXPANSION PLUGS
CHARGE AIR COOLERS "INTERCOOLERS" (CAC)
CHECK VALVES
CHOKES