Gear JEEP CHEROKEE 1988 Service Repair Manual
[x] Cancel search | Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
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specification. Install front cover oil seal. See FRONT COVER OIL SEAL
Remove front cover seal installer.
4) Reverse removal procedures. Lubricate vibration damper
retaining bolt with oil prior to installation. Tighten bolts to
specification.
FRONT COVER OIL SEAL
Removal & Installation
1) Remove vibration damper. Using Seal Remover (J-9256),
remove seal from front cover. Position new seal on Front Cover Seal
Installer (J-22248) with lip facing outward.
2) Apply sealant to seal outer diameter. Lightly coat
crankshaft with oil. Place front cover seal installer on front of
crankshaft. Tap seal into front cover. Remove seal installer. Lightly
coat seal contact area of vibration damper with oil.
3) Install key in crankshaft (if removed). Install vibration\
damper. Lubricate vibration damper bolt with oil. Install retaining
bolt and washer. Tighten to specification.
CAMSHAFT & TIMING GEAR
Removal
1) Drain cooling system. Remove radiator. Remove engine front
cover. See ENGINE FRONT COVER. Remove distributor. Remove fuel pump
(if equipped with mechanical pump). Remove rocker arms and pushrods.
See ROCKER ARMS & BRIDGE under VALVES.
2) Remove valve lifters. Mark lifters for location. Remove
crankshaft oil slinger. Pull chain tensioner block toward tensioner
lever to compress spring. Hold block and move tensioner lever to lock
position. See Fig. 3.
3) Rotate crankshaft and align timing marks on crankshaft and
camshaft gears. Remove camshaft gear retaining bolt. Remove gears and
timing chain. Remove camshaft.
Fig. 3: Location of Chain Tensioner Lock
Courtesy of Chrysler Motors.
Inspection
Inspect camshaft for flaking, lobe wear or worn bearing
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journals. Replace if not within specification. See ENGINE
SPECIFICATIONS tables.
Installation
1) Lubricate camshaft and install. Avoid damage to camshaft
bearings. Install timing gears and timing chain. Rotate crankshaft and
camshaft so timing marks are aligned. See Fig. 4.
2) Install camshaft gear retaining bolt. Tighten to
specification. Install crankshaft oil slinger. Position chain tension
tensioner lever to the unlock (down) position. Reverse removal
procedures to complete installation.
CAUTION: Ensure chain tensioner is released prior to front cover
installation.
Fig. 4: Aligning Timing Marks
CAMSHAFT BEARINGS
Removal & Installation
Replace camshaft bearings using camshaft bearing remover/
installer. Ensure oil holes are aligned after installation.
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1) Drain cooling system. Remove fan shroud and drive belts.
Remove fan assembly.
2) Disconnect heater hoses and lower radiator hose at water
pump. Remove water pump retaining bolts. Remove water pump.
Installation
Clean all gasket surfaces. Install water pump. Tighten bolts
to specification. Ensure pump turns freely. Reverse removal
procedures. Fill and purge air from cooling system.
NOTE: It may be necessary to remove heater hose to remove trapped
air if system cannot be purged using following procedures.
Cooling System Air Purge (Vehicles With Coolant Recovery)
Fill system to proper level. Place heater control to "HEAT"
position and temperature control to "WARM" or "HIGH" position. Install
coolant caps. Operate engine to normal operating temperature. Shut off
engine and allow system to cool. Add coolant to recovery bottle.
Repeat procedure to obtain correct coolant level.
Cooling System Air Purge (Vehicles Without Coolant Recovery)
Fill system to proper level. Place heater control to "HEAT"
position and temperature control to "WARM" or "HIGH" position. Operate
engine to normal operating temperature with radiator cap removed. Add
necessary coolant and install radiator cap.
NOTE: For further information on cooling system capacities and
other cooling system components, see ENGINE COOLING SYSTEMS
article.
ENGINE OILING
CRANKCASE CAPACITY
Crankcase capacity is 4 qts. (3.8 L) with oil filter change.
NORMAL OIL PRESSURE
Normal oil pressure should be 13 psi (.91 kg/cm) at 600 RPM
or 37-75 psi (2.6-5.3 kg/cm) at 1600 RPM.
OIL PRESSURE REGULATOR VALVE
Oil pressure regulator valve is located in oil pump body and
is nonadjustable.
OILING SYSTEM
Engine lubrication is provided by the distributor driven
gear-type oil pump. Oil is supplied through the full-flow oil filter
and into an internal oil passage. Internal passage runs along right
side of block and intersects lifter bores.
Oil is then routed to camshaft and crankshaft bearings. Oil
is supplied to rocker arms from the hydraulic lifters and through the
push rods. By-pass valves are located in oil filter mounting and oil
pump.
OIL PUMP
Removal
Remove oil pan. See OIL PAN REMOVAL article. Remove oil pump
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retaining bolts.
CAUTION: DO NOT move oil pick-up pipe in pump body. If oil pick-up
pipe is moved, pick-up pipe must be replaced to ensure an
airtight seal.
Disassembly & Inspection
Disassemble pump. See Fig. 8. Inspect for wear or damage.
Using straightedge and feeler gauge, measure gear end clearance. See
Fig. 9 . Replace assembly if gear end clearance exceeds specification.
Measure gear-to-body clearance. Replace components as necessary if not
within specification. See OIL PUMP SPECIFICATIONS table.
CAUTION: If relief valve is replaced, ensure replacement valve is
the same diameter as that removed. Different diameter
valves may be used.
Reassembly & Installation
1) Reverse disassembly procedures. Apply Permatex No. 2 to
pick-up pipe prior to installation. Using Pipe Installer (J-21882),
install pick-up pipe. Ensure pick-up pipe support bracket is aligned
with pump cover bolt.
2) Fill pump cavity with petroleum jelly prior to installing
pump cover. Apply Loctite on pump cover area. Install cover and bolts.
Tighten bolts to specification. Check pump gears for freedom of
rotation.
3) Install oil pump and new gasket. Tighten retaining bolts
to specification.
OIL PUMP SPECIFICATIONS
OIL PUMP SPECIFICATIONS TABLE \
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Application In. (mm)
Gear End Clearance ................... .002-.006 (.05-.15)
Gear-to-Body Clearance ............... .002-.004 (.05-.10)
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Fig. 8: Exploded View of Oil Pump Assembly
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![JEEP CHEROKEE 1988 Service Repair Manual Fig. 9: Measuring Oil Pump Gear End Clearance
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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\](/img/16/57037/w960_57037-13.png "JEEP CHEROKEE 1988 Service Repair Manual Fig. 9: Measuring Oil Pump Gear End Clearance
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Fig. 9: Measuring Oil Pump Gear End Clearance
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Application Ft. Lbs. (N.m)
Camshaft Sprocket Bolt .......................... 80 (109)
Connecting Rod Cap Nut ........................... 33 (45)
Cylinder Head Bolt
No. 8 ........................................ 100 (136)
All Others ................................... 110 (149)
Drive Plate-to-Converter Bolt .................... 22 (30)
EGR Valve Pipe Nut ............................... 30 (41)
Exhaust Manifold Bolt ............................ 23 (31)
Fan Bolt ......................................... 18 (24)
Flywheel-to-Crankshaft Bolt .................. ( 1) 50 (68)
Intake Manifold Bolt ............................. 23 (31)
Main Bearing Cap Bolt
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with manifold pressure information.
Knock Sensor
The knock (detonation) sensor, located in the cylinder head,
provides an input signal to the ECU whenever detonation occurs. The
ECU then retards ignition advance to eliminate the detonation at the
applicable cylinders.
Speed Sensor
The speed sensor (or crankshaft position sensor) is mounted
at the flywheel/drive plate housing. The sensor detects the flywheel/
drive plate teeth as they pass during engine operation and sends an
electrical signal to the ECU, which calculates engine speed.
The flywheel/drive plate has a large trigger tooth and notch
located 90
and 12 small teeth before each top dead center (TDC)
position. When a small tooth or notch pass the magnetic core in the
sensor, the build-up and collapse of the magnetic field induces a
small voltage signal in the sensor pick-up windings.
The ECU counts these signals representing the number of teeth
as they pass the sensor. When a larger trigger tooth and notch pass
the magnetic core, a higher voltage signal is sent to the ECU. This
indicates to the ECU that a piston will be at the TDC position 12
teeth later. The ECU either advances or retards ignition timing as
necessary according to sensor inputs.
Battery Voltage
Battery voltage input to the ECU ensures that proper voltage
is applied to the injector. The ECU varies voltage to compensate for
battery voltage fluctuations.
Starter Motor Relay
The engine starter motor relay provides an input to the ECU,
indicating the starter motor is engaged.
Wide Open Throttle (WOT) Switch
The WOT switch is mounted on the side of the throttle body.
The switch provides a voltage signal to the ECU under wide open
throttle conditions. The ECU responds to this signal by enriching the
air/fuel mixture delivered to the injector.
Closed Throttle (Idle) Switch
This switch is integral with the idle speed actuator (ISA)
motor. The switch provides a voltage signal to the ECU, which
increases or decreases the throttle stop angle in response to engine
operating conditions.
Transmission Gear Position Indicator
The gear position indicator is mounted on vehicles equipped
with automatic transaxles. It provides a signal to the ECU to
indicate that the transaxle is in a driving mode and not in Park or
Neutral.
Power Steering Pressure Switch
The switch increases the idle speed during periods of high
power steering pump load and low engine RPM.
A/C Switch
The A/C switch sends a signal to the ECU when the air
conditioner is operating and when the compressor clutch must be
engaged to lower the temperature. The ECU, in turn, increases engine
speed to compensate for the added load of the air conditioner.
FUEL CONTROL
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The ECU controls the A/C compressor clutch by means of the
A/C clutch relay. See Fig. 15.
UP-SHIFT INDICATOR LAMP
Manual transaxle vehicles are equipped with an up-shift
indicator lamp. The lamp is normally turned on when the ignition
switch is turned "ON", and is turned off when the engine starts.
The lamp will again light during engine operation, according
to engine speed and load conditions. A switch, located on the
transaxle, prevents lamp from lighting when transmission is shifted
to the next highest gear. If the shift of gears is not performed, the
ECU will turn the lamp off after 3-5 seconds.
MODES OF OPERATION
IGNITION SWITCH "ON" MODE
When the TBI system is activated by the ignition switch, the
system power relay is energized, and the fuel pump is energized by
the ECU through the fuel pump relay. The pump will operate for
approximately 1 second, unless the engine is operating or the starter
motor is engaged.
The ECU receives input from the CTS, MAT, and MAP sensors.
The up-shift indicator lamp is illuminated.
ENGINE START-UP MODE
When the starter motor is engaged, the ECU receives inputs
from the CTS and speed sensors, the starter motor relay, and the wide
open throttle switch. The fuel pump is activated by the ECU and
voltage is applied to the injector, with the ECU controlling
injection time.
The ECU determines proper ignition timing from the speed
sensor input. If the wide open throttle switch is engaged, the ECU
will deactivate the injector to prevent flooding.
ENGINE WARM-UP MODE
The ECU receives inputs from the CTS, MAT, MAP, speed, and
knock sensors. It also is informed of throttle, gear (automatic
transaxle models) and A/C control position.
The ECU provides a ground for the injector, precisely
controlling fuel delivery to the engine. The ECU also controls
ignition timing, engine idle speed and throttle stop angle. On
vehicles with manual transmissions, the up-shift indicator lamp is
controlled according to engine speed and load.
CRUISE MODE
During cruising speed, the ECU receives inputs from the CTS,
MAT, MAP, EGO, speed and knock sensors. It is also informed of
throttle, gear (automatic transaxle models), and A/C control position.\
The ECU provides a ground to the injector, precisely
controlling injector time. It also controls idle speed, throttle stop
angle, ignition timing, air/fuel mixture ratio and up-shift indicator
lamp.
DECELERATION MODE
During deceleration, the ECU receives inputs from the CTS,
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MAT, MAP, EGO, speed and knock sensors. It also is informed of
throttle, gear (automatic transaxle models) and A/C control position.
When the ECU receives deceleration input from the closed
throttle (idle) switch, it grounds the EGR valve/canister purge
solenoid. This interrupts vacuum to EGR valve and canister purge
function. The injector is grounded, and during rapid deceleration,
the ECU may stop injection for a short period of time. The ECU also
controls engine idle speed and throttle stop angle.
WIDE OPEN THROTTLE MODE
During wide open throttle mode, the ECU receives inputs from
the CST, MAT, MAP, EGO, speed and knock sensors. It also monitors
throttle position.
When the ECU receives deceleration input from the closed
throttle (idle) switch, it grounds the EGR valve/canister purge
solenoid. This interrupts vacuum to EGR valve and canister purge
function. The EGO sensor input is not accepted by the ECU. The
injector is grounded and amount of fuel is precisely controlled.
IGNITION SWITCH "OFF" MODE
When ignition switch is turned "OFF", the ECU ceases to
provide ground for the injector and all fuel injection stops. The ECU
causes the idle speed actuator to fully extend for the next start up.
The ECU then deactivates.
COMPONENT TESTING
NOTE: When test calls for volt-ohmmeter, use of a high impedance
digital type is required.
Fig. 5: Diagnostic Connectors D1 and D2 Terminal Identification
1) Disconnect wiring harness connector from the MAT sensor.
Test resistance of the sensor with an ohmmeter. If resistance is not
185-100,700 ohms (3400 ohms at 70
F; 1600 ohms at 100 F), replace
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Removal
Drain cooling system. Disconnect radiator and heater hoses
from pump. Remove drive belt(s). Remove fan shroud. Remove fan
assembly. Remove electric cooling fan (if equipped). Remove power
steering bracket from water pump. Remove water pump and gasket.
Installation
Ensure gasket surfaces are clean. Install water pump. Tighten
bolts to specification. Ensure pump turns freely. Reverse removal
procedures. Fill and purge air from cooling system.
NOTE: It may be necessary to remove heater hose to remove trapped
air if system cannot be purged using following procedures.
Cooling System Air Purge (Vehicles W/Coolant Recovery)
Fill system to proper level. Place heater control to "HEAT"
position and temperature control to "WARM" or "HIGH" position. Install
coolant caps. Operate engine to normal operating temperature. Shut off
engine and allow system to cool. Add coolant to recovery bottle.
Repeat procedure to obtain correct coolant level.
Cooling System Air Purge (Vehicles W/O Coolant Recovery)
Fill system to proper level. Place heater control to "HEAT"
position and temperature control to "WARM" or "HIGH" position. Operate
engine to normal operating temperature with radiator cap removed. Add
necessary coolant and install radiator cap.
NOTE: For further information on cooling systems, see appropriate
article in the ENGINE COOLING section.
LUBRICATION
CRANKCASE CAPACITY
Crankcase capacity for 4.0L is 5 1/2 qts. (5.2L) or 5 qts.
(4.7L) for 4.2L with oil filter change.
NORMAL OIL PRESSURE
Normal oil pressure should be 37-75 psi (2.6-5.3 kg/cm)
maximum above 1600 RPM. Minimum oil pressure should be 13 psi (.9
kg/cm
) at 600 RPM.
OIL PRESSURE REGULATOR VALVE
Oil pressure regulator valve is located in pump body. Valve
is nonadjustable and serviced as an assembly.
ENGINE OILING SYSTEM
Engine lubrication is provided by the distributor driven
gear-type oil pump. Oil is supplied through the full-flow oil filter
and into an internal oil passage. Internal passage provides oil to the
lifter bores. Oil is then routed to camshaft and crankshaft bearings.
Oil is supplied to rocker arms from the hydraulic lifters and through
the push rods.
OIL PUMP
Removal
Remove oil pan. See OIL PAN REMOVAL in this section. Remove
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oil pump retaining bolts.
CAUTION: DO NOT move oil pick-up pipe in pump body. If oil pick-up
pipe is moved, pick-up pipe must be replaced to ensure an
airtight seal.
Disassembly & Inspection
1) Disassemble pump. See Fig. 8. Use feeler gauge and
straightedge to check gear end clearance. Place straightedge across
gears and pump body. Using feeler gauge, determine thickness feeler
gauge which fits snugly between straightedge and gears.
2) With gears installed in pump body, insert feeler gauge
between gear tooth and inner wall of pump body to check gear-to-body
clearance. Rotate gears and measure clearance at each gear tooth.
3) Compare measurements to specification. See OIL PUMP
SPECIFICATIONS table. Repair as necessary if not within
specifications. Check pressure regulator valve for wear or binding in
pump body. Replace components if wear or binding exists.
OIL PUMP SPECIFICATIONS TABLE
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Application In. (mm)
Gear End Clearance ........... .004-.008 (.10-.20)
Gear-to-Body Clearance ....... .002-.004 (.05-.10)
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CAUTION: If pressure regulator valve is replaced, ensure replacement
valve is the same diameter as that removed. Different
diameter valves may be used.
Reassembly & Installation
1) Reverse procedures for reassembly and installation. Apply
Permatex No. 2 to pick-up pipe prior to installation. Using Pipe
Installer (J-21882), install pick-up pipe. Ensure pick-up pipe support\
bracket is aligned with pump cover bolt.
2) Fill gear cavity with petroleum jelly prior to installing
cover. Apply Loctite on pump cover area. Install cover and bolts.
Tighten bolts to specification. Check pump gears for freedom of
rotation.
3) Install oil pump and new gasket. Tighten retaining bolts
to specification.
Fig. 8: Exploded View of Oil Pump Assembly
Courtesy of Chrysler Motors.
TORQUE SPECIFICATIONS TABLE