1988 JEEP CHEROKEE engine

PO W ER S TE ER IN G P U M P

1988 J e ep C hero ke e
1988 STEERING
Jeep Power Steering Pumps - Saginaw Vane-Type
Cherokee, Comanche, Grand Wagoneer, Pickup, Wagoneer,
Wrangler
DESCRIPTION
Saginaw vane-type power steering pump can be identified by
"ham-shaped" fluid reservoir can. Rectangular pumping vanes carried by
a shaft driven rotor move fluid from intake to pressure cavities of
cam ring.
Centrifugal force throws vanes against inside surface of cam
ring to pick up residual oil. As more oil is picked up, it is forced
into cavities of thrust plate, into 2 cross-over holes in cam ring and
pressure plate and into a high pressure area between pressure plate
and housing end plate.
Filling the high pressure area causes oil to flow under vanes
in slots of rotor. This forces vanes to follow inside oval surface of
cam ring. As vanes rotate to small area of cam ring, oil is forced out
from between vanes.
TROUBLE SHOOTING
Refer to TROUBLE SHOOTING - BASIC PROCEDURES article in the
GENERAL TROUBLE SHOOTING section.
LUBRICATION & TESTING
See POWER STEERING GENERAL SERVICING article in the STEERING
section.
REMOVAL & INSTALLATION
POWER STEERING PUMP
Removal & Installation
1) Loosen pump adjusting bolt (or nut) and pump mounting
bolts. Remove pump drive belt. Disconnect pressure and return hoses
from pump. Cap ends to prevent loss of fluid or contamination.
2) Remove pump bracket-to-engine bolts. Remove pump, pulley
and mounting bracket as an assembly. To install, reverse removal
procedure. Bleed system.
OVERHAUL
CAUTION: When clamping pump in vise, be careful not to exert
excessive force on front hub or pump. DO NOT use hammer to
remove pulley.
DISASSEMBLY
1) Drain pump reservoir. Clean exterior of unit. Remove
mounting bracket(s). Using a puller, withdraw pulley from shaft. See
Fig. 1 .

PVC & C RAN KCASE V EN TIL A TIO N S YSTE M

1988 J e ep C hero ke e
1987-89 Crankcase Ventilation
PCV AND CCV SYSTEMS
Jeep
DESCRIPTION
Crankcase ventilation systems are designed to prevent
contaminating hydrocarbons from escaping to the atmosphere. This is
accomplished by routing vapors from the crankcase through a
vacuum-controlled ventilating valve (PCV Valve) into the intake
manifold. In the intake manifold, the crankcase vapors mix with the
air/fuel mixture and are burned in the combustion process. PCV systems
are used on all 4.2L and 5.9L engines. 2.5L and 4.0L engines do not
employ PCV systems, instead they are equipped with a Crankcase
Ventilation System (CCV). The CCV system performs the same function as\
a conventional PCV system, but does not use a vacuum controlled valve.
OPERATION
PCV SYSTEM
Air is supplied to the crankcase ventilation system through
a crankcase ventilating filter assembly, located in air cleaner
housing or on rocker arm cover.
When engine is operating, fresh air enters crankcase
ventilation system through the air cleaner and filter.
Air then flows into the rocker arm cover and valve
compartment. It combines with blow-by gas and unburned air/fuel
mixture and burns in combustion chamber. See Fig. 1.
Fig. 1: Typical Crankcase Ventilation System
Ventilator valve is held closed by spring pressure when
engine is not running. See Fig. 2. This prevents accumulation of
hydrocarbon fumes from collecting in intake manifold, which could

result in hard starting.
Fig. 2: Typical PCV Valve & Airflow
When engine is started, manifold vacuum pulls valve open
against spring pressure. As long as there is engine vacuum, the valve
floats, permitting crankcase fumes to enter intake manifold.
A baffle in rocker arm cover prevents oil from being drawn
into intake manifold through ventilator valve.
If the engine backfires, the ventilator valve will close.
This will prevent ignition of fumes in crankcase.
During certain engine operations, more blow-by is created
than ventilator valve can handle. Excess blow-by is returned to air
cleaner and carburetor through rocker arm cover and breather
assembly. It is then burned in the combustion chamber.
A breather assembly acts as separator to keep oil from being
drawn into air cleaner during this operation.
CCV SYSTEM
As stated above, the CCV system performs the same function
as a conventional PCV system, but does not use a vacuum controlled
valve.
A molded vacuum tube connects manifold vacuum to a grommet on
top of the cylinder head cover at the dash panel end. The grommet
contains a metered orifice of a calibrated size that meters the amount
of crankcase vapors drawn out of the engine. A fresh air supply hose
from the air cleaner is also connected to the front of the cylinder
head cover on 4.0L engines and to the rear of the cover on 2.5L
engines.
When the engine is operating, fresh air enters the engine
and mixes with crankcase vapors. Manifold vacuum draws the
vapor/air mixture through the metered orifice and into the intake
manifold. The vapors are consumed during combustion.

Fig. 3: CCV System 2.5L Engine
Fig. 4: CCV System 4.0L Engine
TESTING

To test crankcase ventilation system, start engine and allow
it to reach normal operating temperature. Make sure engine is idling
at normal curb idle, and perform following checks:
1) Remove PCV valve from its mounting. If valve is
functioning properly, hissing noise will be heard as air passes
through it. Strong vacuum should be felt when your finger is placed
over valve inlet.
2) While finger is over inlet, check for presence of vacuum
leaks in hose line and at all connections. Reinstall PCV valve,
remove crankcase air inlet hose at air cleaner.
3) Loosely hold piece of stiff paper over opening at end of
inlet hose. Paper should be sucked against hose opening with
noticeable force after sufficient time has elapsed for crankcase
pressure to lower (usually about a minute). For final check, stop
engine, remove PCV valve and shake it. Metallic clicking noise should
be heard, indicating valve is free.
4) If system passes both engine running and stopped tests,
it is functioning properly. No further tests are required. If it has
failed either test, replace appropriate components and retest. If it
does not pass on second try, clean system.
MAINTENANCE
Engine may idle slow or rough due to clogged ventilator
valve or system. Therefore, never adjust carburetor idle without
first checking valve and system.
If ventilator valve or system becomes clogged, all crankcase
ventilation will stop, and serious engine damage could result.
Although following manufacturers' service procedures give
specific intervals, it is recommended the crankcase ventilation
system be checked more frequently if vehicle is operated under severe
conditions (extreme dust, prolonged idling, trailer hauling or short
trips in cold weather).
PCV VALVE
Replace PCV valve every 30,000 miles. Valve is located on
rocker arm cover of 4-cylinder, 6-cylinder and V6 models and on
intake manifold of V8 models.
FILTER ELEMENT
Clean filter element every 30,000 miles. Filter is located
inside air cleaner of 4-cylinder, 6-cylinder and V6 models and in oil
filler cap of V8 models.

\003
REC ALL 5 61 - 4 .0 L E N G . F E D . V EH IC LE S - O XYG EN S EN SO R

1988 J e ep C hero ke e
EMISSION RECALL BULLETIN
EMISSIONS RECALL #561 - OXYGEN SENSOR
Model(s): 1987-90 (XJ) Jeep Cherokee, Wagoneer
1987-90 (MJ) Jeep Comanche
Bulletin No.: 561
Date: October, 1993
NOTE: This is an Emission Recall bulletin.
VEHICLES AFFECTED
1987-90 Jeep Cherokee and Wagoneer (XJ); and Comanche (MJ) vehicle\
s
equipped with a 4.0L engine and located outside of California.
SERVICE INFORMATION
Failure of the oxygen sensor on the listed models, may cause a
vehicle to be in violation of Federal Emissions Standards. To correct
the condition, the oxygen sensor must be replaced with an improved
design sensor.
Details of this service action are explained in the following
sections.
SERVICE PROCEDURE VIDEOTAPE
No videotape of the service procedure for this recall will be
provided.
DEALER NOTIFICATION & VEHICLE LIST
INVOLVED DEALERS
Each dealer to whom involved vehicles were invoiced (or the current
dealer at the same street address) will receive a copy of this dealer
recall notification letter and a list of the involved vehicles by
first class mail.
The Vehicle List is arranged in Vehicle Identification Number (VIN)
sequence. Owners known to Chrysler are also listed. The lists are for
dealer reference in arranging for service of involved vehicles.
ALL DEALERS
Each Jeep & Eagle dealer will receive a copy of this dealer recall
notification letter by first class mail.
DIAL SYSTEM FUNCTION 70
All involved vehicles will be entered to DIAL System Function 70 at
the time of recall implementation for dealer inquiry by VIN as needed.
PARTS INFORMATION

IMPORTANT: A quantity of parts will be distributed initially and
billed to all involved dealers. This quantity will cover a
portion of the total vehicles involved. Additional parts
will ba supplied as indicated in the Special Parts Supply
Message with this notification letter.
Each involved dealer, to whom vehicles in the recall were invoiced
(or the current dealer at the same street address), will receive
enough Oxygen Sensor Packages, Recall P/N C3905610, to service 25% of
those vehicles (minimum of 5 and maximum of 20 packages).
Each uninvolved dealer will receive 5 parts packages to service
vehicles upon request.
Each parts package contains the following components:
PARTS INFORMATION
PARTS INFORMATION TABLE







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Description  Qty. 










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Oxygen Sensor  1 










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Instruction Sheet  1 











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OWNER NOTIFICATION & SERVICE SCHEDULING
All involved vehicle owners known to Chrysler are being notified of
the service requirement by first class mail. They are requested to
schedule appointments for the service with their dealers at the
earliest possible date. A copy of the
CUSTOMER NOTIFICATION LETTER is
in this bulletin.
Enclosed with each owner notification is an Owner Notification Form.
The involved vehicle and recall are identified on the form for owner
or dealer reference as needed.
SERVICE PROCEDURE
A. OXYGEN SENSOR INSPECTION
1. Raise Vehicle on a hoist and locate oxygen sensor in exhaust
manifold as shown in Fig. 1.
a. If the oxygen sensor has a metal stone shield around the sensor
body continue with Step B.
b. If the sensor does not have a stone shield, a new sensor has
already been installed and no further service is required.
WARNING: Exhaust manifold becomes very hot during engine operation.
Allow engine to cool before removing oxygen sensor.
1. Disconnect the oxygen sensor electrical connector.
2. Remove oxygen sensor using a crowfoot socket.
3. Clean exhaust manifold threads.









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EMISSIONS RECALL - OXYGEN SENSOR REPLACEMENT
Dear Chrysler Vehicle Owner:
Chrysler Corporation and the Environmental Protection Agency has
determined that the oxygen sensor on certain Cherokee, Wagoneer and
Comanche models may be susceptible to failure. Failure of the oxygen
sensor may cause your vehicle to be in violation of Federal Emissions
Standards. For this reason, we are asking you to return your vehicle,
identified by the Vehicle Identification Number on the enclosed form,
to your dealer for a special service repair. This service will be
provided free of charge.
The needed instructions have been sent to all involved dealers. The
service will not hurt your engine performance or fuel economy. To
obtain this service:
* Contact your Jeep/Eagle dealer as soon as possible to make an
appointment for the free service.
* Take the enclosed Owner Notification Form with you at the time of
your appointment and give it to your dealer. The form identifies
the vehicle and recall for which service is required.
* The dealer will inspect and replace the oxygen sensor if
necessary. The service will take about one-half hour, but
additional time may be required depending on how service
appointments are scheduled and processed.
In order to ensure your full protection under the emission warranty
made applicable to your vehicle under Federal law, and your right to
participate in future recalls, it is recommended that you have your
vehicle serviced as soon as possible. Failure to do so could legally
be determined to be a lack of proper maintenance of your vehicle.
Further, without this repair your vehicle may fail a state or local
emission inspection test.
If you have any problem obtaining the service, please contact the
Chrysler Zone Service Office in your area. (It is listed under
"Service Assistance" in your Owner's Manual.} A Zone representative
will arrange for prompt servicing of your vehicle. If you are still
unable to obtain the repair as described in this letter within a
reasonable time, you may also contact the Manufacturers Operations
Division of the Environmental Protection Agency (6405d), 401 M Street
S. W., Washington, D. C. 20460.
We regret any inconvenience this action may cause, but trust you
understand our interest in clean air and in your continuing
satisfaction with our product. Thank you for your prompt attention to
this important matter.
Customer Services Field Operations
Chrysler Corporation









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COMPLETION REPORTING & REIMBURSEMENT
Claims for vehicles which have been serviced must be submitted on
the DIAL System. Claims submitted will be used by Chrysler to record
recall service completions and provide dealer payments.