turn JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

(23) Inspect for pinched or leaking fuel tubes/lines.
Inspect for pinched, cracked or leaking fuel hoses.
(24) Inspect for exhaust system restrictions such
as pinched exhaust pipes, collapsed muffler or
plugged catalytic convertor.
(25) If equipped with automatic transmission, ver-
ify electrical harness is firmly connected to park/neu-
tral switch and to transmission components.
(26) Verify fuel pump module pigtail harness elec-
trical connector (Fig. 15) is firmly connected to body
harness connector.
(27) Inspect fuel line harness (from fuel pump
module) at fuel filter/fuel pressure regulator (Fig. 15)
for chaffing, cracks or leaks.
(28) Verify battery cable and solenoid feed wire
connections to starter solenoid are tight and clean.
(29) Inspect for chaffed wires or wires rubbing up
against other components.
(30) Inspect for chaffed vacuum lines or lines rub-
bing up against other components.
Fig. 15 Fuel Filter/Fuel Pressure Regulator Location
1 - FUEL RETURN LINE
2 - FUEL SUPPLY LINE (TO FUEL RAIL)
3 - FUEL FILTER/FUEL PRESSURE REGULATOR
4 - FUEL PRESSURE LINE
5 - REAR AXLE
6 - ELEC. CONNECTOR
7 - EVAP LINE
14 - 38 FUEL INJECTIONWJ
FUEL INJECTION (Continued)

(2) Disconnect CKP electrical connector at sensor
(Fig. 22).
(3) Remove CKP mounting bolt (Fig. 23).
(4) Carefully twist sensor from cylinder block.(5) Remove sensor from vehicle.
(6) Check condition of sensor o-ring.
INSTALLATION
INSTALLATION - 4.0L
The Crankshaft Position (CKP) sensor is mounted
to the transmission bellhousing at the left/rear side
of the engine block (Fig. 21). The sensoris adjust-
ableand is attached with one bolt. A wire shield/
router is attached to the sensor (Fig. 21).
New replacement sensors will be equipped with a
paper spacer glued to bottom of sensor. If installing
(returning) ausedsensor to vehicle, a new paper
spacer must be installed to bottom of sensor. This
spacer will be ground off the first time engine is
started. If spacer is not used, sensor will be broken
the first time engine is started.
(1) New Sensors: Be sure paper spacer is installed
to bottom of sensor. If not, obtain spacer
PN05252229.
(2) Used Sensors: Clean bottom of sensor and
install spacer PN05252229.
(3) Install sensor into transmission bellhousing
hole.
(4) Position sensor wire shield to sensor (Fig. 21).
Fig. 21 CKP SensorÐ4.0L 6-Cylinder Engine
1 - SLOTTED HOLE
2 - CRANKSHAFT POSITION SENSOR
3 - WIRE SHIELD
4 - MOUNTING BOLT
5 - TRANSMISSION HOUSING
6 - PAPER SPACER
Fig. 22 CKP Sensor LocationÐ4.7L V±8 Engine
1 - CRANKSHAFT POSITION SENSOR
2-STARTER
3 - ELEC. CONNECTOR
Fig. 23 CKP Sensor Removal/InstallationÐ4.7L V±8
Engine
1 - CRANKSHAFT POSITION SENSOR
2 - MOUNTING BOLT
14 - 42 FUEL INJECTIONWJ
CRANKSHAFT POSITION SENSOR (Continued)

The PCM determines injector on-time (pulse width)
based on various inputs.
DIAGNOSIS AND TESTING - FUEL INJECTOR
To perform a complete test of the fuel injectors and
their circuitry, use the DRB scan tool and refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the injector only, refer to the following:
Disconnect the fuel injector wire harness connector
from the injector. The injector is equipped with 2
electrical terminals (pins). Place an ohmmeter across
the terminals. Resistance reading should be approxi-
mately 12 ohms  1.2 ohms at 20ÉC (68ÉF).
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT PRESSURE EVEN WITH ENGINE OFF.
BEFORE SERVICING FUEL INJECTOR(S), FUEL
SYSTEM PRESSURE MUST BE RELEASED.
To remove one or more fuel injectors, the fuel rail
assembly must be removed from engine.
(1) Perform Fuel System Pressure Release Proce-
dure.
(2) Remove fuel injector rail. Refer to Fuel Injector
Rail Removal/Installation.
(3) Remove clip(s) retaining injector(s) to fuel rail
(Fig. 25).
(4) Remove injector(s) from fuel rail.
INSTALLATION
(1) Apply a small amount of engine oil to each fuel
injector o-ring. This will help in fuel rail installation.
(2) Install injector(s) and injector clip(s) to fuel
rail.
(3) Install fuel rail assembly. Refer to Fuel Injector
Rail Removal/Installation.
(4) Start engine and check for leaks.
FUEL PUMP RELAY
DESCRIPTION
The 5±pin, 12±volt, fuel pump relay is located in
the Power Distribution Center (PDC). Refer to the
label on the PDC cover for relay location.
OPERATION
The Powertrain Control Module (PCM) energizes
the electric fuel pump through the fuel pump relay.
The fuel pump relay is energized by first applying
battery voltage to it when the ignition key is turned
ON, and then applying a ground signal to the relay
from the PCM.
Whenever the ignition key is turned ON, the elec-
tric fuel pump will operate. But, the PCM will shut-
down the ground circuit to the fuel pump relay in
approximately 1±3 seconds unless the engine is oper-
ating or the starter motor is engaged.
IDLE AIR CONTROL MOTOR
DESCRIPTION
The IAC stepper motor is mounted to the throttle
body, and regulates the amount of air bypassing the
control of the throttle plate. As engine loads and
ambient temperatures change, engine rpm changes.
A pintle on the IAC stepper motor protrudes into a
passage in the throttle body, controlling air flow
through the passage. The IAC is controlled by the
Powertrain Control Module (PCM) to maintain the
target engine idle speed.
OPERATION
At idle, engine speed can be increased by retract-
ing the IAC motor pintle and allowing more air to
pass through the port, or it can be decreased by
restricting the passage with the pintle and diminish-
ing the amount of air bypassing the throttle plate.
The IAC is called a stepper motor because it is
moved (rotated) in steps, or increments. Opening the
IAC opens an air passage around the throttle blade
which increases RPM.Fig. 25 Fuel Injector MountingÐTypical (4.7L V-8
Engine Shown)
1 - INLET FITTING
2 - FUEL INJECTOR RAIL
3 - CLIP
4 - FUEL INJECTOR
14 - 44 FUEL INJECTIONWJ
FUEL INJECTOR (Continued)

INSTALLATION
INSTALLATION - 4.0L
The IAC motor is located on the throttle body.
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air cleaner duct/air box to throttle body.
INSTALLATION - 4.7L
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air duct/air box to throttle body.
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION
The 2±wire Intake Manifold Air Temperature (IAT)
sensor is installed in the intake manifold with the
sensor element extending into the air stream.
The IAT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as intake mani-
fold temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
The IAT sensor provides an input voltage to the
Powertrain Control Module (PCM) indicating the
density of the air entering the intake manifold based
upon intake manifold temperature. At key-on, a
5±volt power circuit is supplied to the sensor from
the PCM. The sensor is grounded at the PCM
through a low-noise, sensor-return circuit.
The PCM uses this input to calculate the following:
²Injector pulse-width
²Adjustment of spark timing (to help prevent
spark knock with high intake manifold air-charge
temperatures)
The resistance values of the IAT sensor is the same
as for the Engine Coolant Temperature (ECT) sensor.
REMOVAL
REMOVAL - 4.0L
The Intake Manifold Air Temperature (IAT) sensor
is installed into the intake manifold plenum near the
front of the throttle body (Fig. 27).
(1) Disconnect electrical connector from sensor.
(2) Remove sensor from intake manifold.
REMOVAL - 4.7L
The Intake Manifold Air Temperature (IAT) sensor
is located on the left side of the intake manifold.
Threaded Type Sensor
(1) Disconnect electrical connector from sensor.
(2) Remove sensor from intake manifold (Fig. 28).
Snap-In Type Sensor
(1) Disconnect electrical connector from IAT sen-
sor.
(2) Clean dirt from intake manifold at sensor base.
(3) Gently lift on small plastic release tab (Fig. 30)
or (Fig. 29) and rotate sensor about 1/4 turn counter-
clockwise for removal.
(4) Check condition of sensor o-ring.
Fig. 27 Intake Manifold Air Sensor LocationÐ4.0L
Engine
1 - MOUNTING BOLTS (4)
2 - THROTTLE BODY
3 - IAC MOTOR
4 - ELEC. CONN.
5 - TPS
6 - MAP SENSOR
7 - ELEC. CONN.
8 - IAT SENSOR
9 - ELEC. CONN.
14 - 46 FUEL INJECTIONWJ
IDLE AIR CONTROL MOTOR (Continued)

MAP SENSOR
DESCRIPTION
DESCRIPTION
On the 4.0L six-cylinder engine the MAP sensor is
mounted to the engine throttle body. On the 4.7L V-8
engine the MAP sensor is mounted to front of the
intake manifold.
DESCRIPTION - 4.7L
The MAP sensor is located on the front of the
intake manifold. An o-ring seals the sensor to the
intake manifold.
OPERATION
The MAP sensor is used as an input to the Power-
train Control Module (PCM). It contains a silicon
based sensing unit to provide data on the manifold
vacuum that draws the air/fuel mixture into the com-
bustion chamber. The PCM requires this information
to determine injector pulse width and spark advance.
When manifold absolute pressure (MAP) equals
Barometric pressure, the pulse width will be at max-
imum.
A 5 volt reference is supplied from the PCM and
returns a voltage signal to the PCM that reflects
manifold pressure. The zero pressure reading is 0.5V
and full scale is 4.5V. For a pressure swing of 0±15
psi, the voltage changes 4.0V. To operate the sensor,
it is supplied a regulated 4.8 to 5.1 volts. Ground is
provided through the low-noise, sensor return circuit
at the PCM.
The MAP sensor input is the number one contrib-
utor to fuel injector pulse width. The most important
function of the MAP sensor is to determine baromet-
ric pressure. The PCM needs to know if the vehicle is
at sea level or at a higher altitude, because the air
density changes with altitude. It will also help to cor-
rect for varying barometric pressure. Barometric
pressure and altitude have a direct inverse correla-
tion; as altitude goes up, barometric goes down. At
key-on, the PCM powers up and looks at MAP volt-
age, and based upon the voltage it sees, it knows the
current barometric pressure (relative to altitude).
Once the engine starts, the PCM looks at the voltage
again, continuously every 12 milliseconds, and com-
pares the current voltage to what it was at key-on.
The difference between current voltage and what it
was at key-on, is manifold vacuum.
During key-on (engine not running) the sensor
reads (updates) barometric pressure. A normal range
can be obtained by monitoring a known good sensor.
As the altitude increases, the air becomes thinner
(less oxygen). If a vehicle is started and driven to avery different altitude than where it was at key-on,
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open Throttle (WOT), based
upon Throttle Position Sensor (TPS) angle and RPM,
it will update barometric pressure in the MAP mem-
ory cell. With periodic updates, the PCM can make
its calculations more effectively.
The PCM uses the MAP sensor input to aid in cal-
culating the following:
²Manifold pressure
²Barometric pressure
²Engine load
²Injector pulse-width
²Spark-advance programs
²Shift-point strategies (certain automatic trans-
missions only)
²Idle speed
²Decel fuel shutoff
The MAP sensor signal is provided from a single
piezoresistive element located in the center of a dia-
phragm. The element and diaphragm are both made
of silicone. As manifold pressure changes, the dia-
phragm moves causing the element to deflect, which
stresses the silicone. When silicone is exposed to
stress, its resistance changes. As manifold vacuum
increases, the MAP sensor input voltage decreases
proportionally. The sensor also contains electronics
that condition the signal and provide temperature
compensation.
The PCM recognizes a decrease in manifold pres-
sure by monitoring a decrease in voltage from the
reading stored in the barometric pressure memory
cell. The MAP sensor is a linear sensor; meaning as
pressure changes, voltage changes proportionately.
The range of voltage output from the sensor is usu-
ally between 4.6 volts at sea level to as low as 0.3
volts at 26 in. of Hg. Barometric pressure is the pres-
sure exerted by the atmosphere upon an object. At
sea level on a standard day, no storm, barometric
pressure is approximately 29.92 in Hg. For every 100
feet of altitude, barometric pressure drops .10 in. Hg.
If a storm goes through it can change barometric
pressure from what should be present for that alti-
tude. You should know what the average pressure
and corresponding barometric pressure is for your
area.
REMOVAL
REMOVAL - 4.0L
The MAP sensor is mounted to the side of the
throttle body (Fig. 40). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
31).
(1) Remove air cleaner duct and air resonator box
at throttle body.
14 - 48 FUEL INJECTIONWJ

The other two heater elements (downstream sen-
sors 1/2 and 2/2) are controlled by the downstream
heater relay through output signals from the PCM.
To avoid a large simultaneous current surge, power
is delayed to the 2 downstream heater elements by
the PCM for approximately 2 seconds.
REMOVAL
(1) Remove PDC cover.
(2) Remove relay from PDC.
(3) Check condition of relay terminals and PDC
connector terminals for damage or corrosion. Repair
if necessary before installing relay.
(4) Check for pin height (pin height should be the
same for all terminals within the PDC connector).
Repair if necessary before installing relay.
INSTALLATION
(1) Install relay to PDC.
(2) Install cover to PDC.
O2S SENSOR
DESCRIPTION
The Oxygen Sensors (O2S) are attached to, and
protrude into the vehicle exhaust system. Depending
on the emission package, the vehicle may use a total
of either 2 or 4 sensors.
Federal Emissions Package:Two sensors are
used: upstream (referred to as 1/1) and downstream
(referred to as 1/2). With this emission package, the
upstream sensor (1/1) is located just before the main
catalytic convertor. The downstream sensor (1/2) is
located just after the main catalytic convertor.
4.7L V-8 With California Emissions Package:
On this emissions package, 4 sensors are used: 2
upstream (referred to as 1/1 and 2/1) and 2 down-
stream (referred to as 1/2 and 2/2). With this emis-
sion package, the right upstream sensor (2/1) is
located in the right exhaust downpipe just before the
mini-catalytic convertor. The left upstream sensor
(1/1) is located in the left exhaust downpipe just
before the mini-catalytic convertor. The right down-
stream sensor (2/2) is located in the right exhaust
downpipe just after the mini-catalytic convertor, and
before the main catalytic convertor. The left down-
stream sensor (1/2) is located in the left exhaust
downpipe just after the mini-catalytic convertor, and
before the main catalytic convertor.
4.0L 6±Cylinder With California Emissions
Package:On this emissions package, 4 sensors are
used: 2 upstream (referred to as 1/1 and 2/1) and 2
downstream (referred to as 1/2 and 2/2). With this
emission package, the rear/upper upstream sensor
(2/1) is located in the exhaust downpipe just beforethe rear mini-catalytic convertor. The front/upper
upstream sensor (1/1) is located in the exhaust down-
pipe just before the front mini-catalytic convertor.
The rear/lower downstream sensor (2/2) is located in
the exhaust downpipe just after the rear mini-cata-
lytic convertor, and before the main catalytic conver-
tor. The front/lower downstream sensor (1/2) is
located in the exhaust downpipe just after the front
mini-catalytic convertor, and before the main cata-
lytic convertor.
OPERATION
An O2 sensor is a galvanic battery that provides
the PCM with a voltage signal (0-1 volt) inversely
proportional to the amount of oxygen in the exhaust.
In other words, if the oxygen content is low, the volt-
age output is high; if the oxygen content is high the
output voltage is low. The PCM uses this information
to adjust injector pulse-width to achieve the
14.7±to±1 air/fuel ratio necessary for proper engine
operation and to control emissions.
The O2 sensor must have a source of oxygen from
outside of the exhaust stream for comparison. Cur-
rent O2 sensors receive their fresh oxygen (outside
air) supply through the O2 sensor case housing.
Four wires (circuits) are used on each O2 sensor: a
12±volt feed circuit for the sensor heating element; a
ground circuit for the heater element; a low-noise
sensor return circuit to the PCM, and an input cir-
cuit from the sensor back to the PCM to detect sen-
sor operation.
Oxygen Sensor Heaters/Heater Relays:
Depending on the emissions package, the heating ele-
ments within the sensors will be supplied voltage
from either the ASD relay, or 2 separate oxygen sen-
sor relays. Refer to Wiring Diagrams to determine
which relays are used.
The O2 sensor uses a Positive Thermal Co-efficient
(PTC) heater element. As temperature increases,
resistance increases. At ambient temperatures
around 70ÉF, the resistance of the heating element is
approximately 4.5 ohms on 4.0L engines. It is
approximately 13.5 ohms on the 4.7L engine. As the
sensor's temperature increases, resistance in the
heater element increases. This allows the heater to
maintain the optimum operating temperature of
approximately 930É-1100ÉF (500É-600É C). Although
the sensors operate the same, there are physical dif-
ferences, due to the environment that they operate
in, that keep them from being interchangeable.
Maintaining correct sensor temperature at all
times allows the system to enter into closed loop
operation sooner. Also, it allows the system to remain
in closed loop operation during periods of extended
idle.
14 - 50 FUEL INJECTIONWJ
O2S HEATER RELAY (Continued)

STEERING
TABLE OF CONTENTS
page page
STEERING
DESCRIPTION - POWER STEERING SYSTEM . . 1
OPERATION - POWER STEERING SYSTEM . . . 1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER
STEERING SYSTEM....................2
DIAGNOSIS AND TESTING - STEERING
FLOW AND PRESSURE.................4DIAGNOSIS AND TESTING - 4.7L -
HYDRAULIC..........................5
COLUMN...............................7
GEAR.................................16
LINKAGE..............................26
PUMP.................................31
STEERING
DESCRIPTION - POWER STEERING SYSTEM
The power steering pump (Fig. 1) is a constant
flow rate and displacement vane type pump. The
pump reservoir is attached to the pump body. The
pump is connected to the steering by the pressure
and return hoses. The steering gear (Fig. 1) used is a
recirculating ball type gear. A tilt and non-tilt column
provide steering input.
The power steering system consists of:
OPERATION - POWER STEERING SYSTEM
The rack piston balls act as a rolling thread
between the worm shaft and rack piston. The worm
shaft is supported by a thrust bearing at the lower
end and a bearing assembly at the upper end. When
the worm shaft is turned from input from the steer-
ing column the rack piston moves. The rack piston
teeth mesh with the pitman shaft. Turning the worm
shaft turns the pitman shaft, which moves the steer-
ing linkage.
Fig. 1 POWER STEERING GEAR & PUMP 4.0L
1 - STEERING GEAR
2 - PRESSURE HOSE
3 - PUMP
4 - RETURN HOSE
5 - RESERVOIR
WJSTEERING 19 - 1

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER STEERING SYSTEM
STEERING NOISE
There is some noise in all power steering systems. One of the most common is a hissing sound evident at a
standstill parking. Or when the steering wheel is at the end of it's travel. Hiss is a high frequency noise similar
to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing
through an orifice. There is no relationship between this noise and steering performance.
CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONAL HISS OR
WHISTLE1. Steering intermediate shaft to dash panel
seal.1. Check and repair seal at dash
panel.
2. Noisy valve in power steering gear. 2. Replace steering gear.
RATTLE OR CLUNK 1. Gear mounting bolts loose. 1. Tighten bolts to specification.
2. Loose or damaged suspension
components/track bar.2. Inspect and repair suspension.
3. Loose or damaged steering linkage. 3. Inspect and repair steering
linkage.
4. Internal gear noise. 4. Replace gear.
5. Pressure hose in contact with other
components.5. Reposition hose.
CHIRP OR SQUEAL 1. Loose belt. 1. Adjust or replace.
2. Belt routing. 2. Verify belt routing is correct.
WHINE OR GROWL 1. Low fluid level. 1. Fill to proper level.
2. Pressure hose in contact with other
components.2. Reposition hose.
3. Internal pump noise. 3. Replace pump.
4. Air in the system. 4. Perform pump initial operation.
SUCKING AIR SOUND 1. Loose return line clamp. 1. Replace clamp.
2. O-ring missing or damaged on hose
fitting.2. Replace o-ring.
3. Low fluid level. 3. Fill to proper level.
4. Air leak between pump and reservoir. 4. Repair as necessary.
SCRUBBING OR
KNOCKING1. Wrong tire size. 1. Verify tire size.
2. Wrong gear. 2. Verify gear.
19 - 2 STEERINGWJ
STEERING (Continued)

BINDING AND STICKING
CONDITION POSSIBLE CAUSE CORRECTION
DIFFICULT TO TURN WHEEL
STICKS OR BINDS1. Low fluid level. 1. Fill to proper level.
2. Tire pressure. 2. Adjust tire pressure.
3. Steering component. 3. Inspect and lube.
4. Loose belt. 4. Adjust or replace.
5. Low pump pressure. 5. Pressure test and replace if
necessary.
6. Column shaft coupler binding. 6. Replace coupler.
7. Steering gear worn or out of
adjustment.7. Repair or replace gear.
8. Ball joints binding. 8. Inspect and repair as necessary.
9. Belt routing. 9. Verify belt routing is correct.
4.7L Hydraulic fan motor steering output
lowPressure / Flow test fans steering
output flow
INSUFFICIENT ASST. OR POOR RETURN TO CENTER
CONDITION POSSIBLE CAUSE CORRECTION
HARD TURNING OR MOMENTARY
INCREASE IN TURNING EFFORT1. Tire pressure. 1. Adjust tire pressure.
2. Low fluid level. 2. Fill to proper level.
3. Loose belt. 3. Adjust or replace.
4. Lack of lubrication. 4. Inspect and lubricate steering and
suspension compnents.
5. Low pump pressure or flow. 5. Pressure and flow test and repair
as necessary.
6. Internal gear leak. 6. Pressure and flow test, and repair
as necessary.
7. Belt routing. 7. Verify belt routing is correct.
4.7L8. Low flow / pressure from fan
motor8. Pressure and flow test and repair
as necessary.
STEERING WHEEL
DOES NOT WANT TO RETURN TO
CENTER POSITION1. Tire pressure. 1. Adjust tire pressure.
2. Wheel alignment. 2. Align front end.
3. Lack of lubrication. 3. Inspect and lubricate steering and
suspension compnents.
4. High friction in steering gear. 4. Test and adjust as necessary.
5. Ball joints binding. 5. Inspect and repair as necessary.
NOTE:
Some roads will cause a vehicle to drift, due to the crown in the road.
WJSTEERING 19 - 3
STEERING (Continued)

(8) Start engine and let idle long enough to circu-
late power steering fluid through flow/pressure test
gauge.
(9) Shut off the engine and check the fluid level,
add fluid as necessary. Start engine again and let
idle.
(10) The initial pressure reading should be
345-552 kPa (50-80 psi). If pressure is higher inspect
the hoses for restrictions and repair as necessary.
(11) Increase the engine speed to 1500 RPM and
read the flow meter. The reading should be 2.4 - 2.8
GPM, if the reading is below this specification the
pump should be replaced.
CAUTION: This next step involves testing maximum
pump pressure output and flow control valve oper-
ation. Do not leave valve closed for more than three
seconds as the pump could be damaged.
(12) Close valve fully three times for three seconds
and record highest pressure indicated each time.All
three readings must be at pump relief pressure
specifications and within 345 kPa (50 psi) of
each other.
²Pressures above specifications but not within
345 kPa (50 psi) of each other, replace pump.
²Pressures within 345 kPa (50 psi) of each other
but below specifications, replace pump.
CAUTION: Do not force the pump to operate against
the stops for more than 2 to 4 seconds at a time
because, pump damage will result.
(13) Open the test valve and turn the steering
wheel to the extreme left and right positions against
the stops. Record the highest pressure reading at
each position. Compare readings to the pump specifi-
cations chart. If pressures readings are not within 50
psi. of each other, the gear is leaking internally and
must be repaired.
GEAR INLET SPECIFICATIONS 4.0L & 4.7L
ENGINERELIEF
PRESSURE   50FLOW RATE
(GPM)
4.0L 9653 kPa (1400 psi)
1500 RPM 2.4 - 2.8
GPM
4.7L 9653 kPa (1450 psi)
PUMP MOTOR SPECIFICATIONS 4.7L
ENGINERELIEF
PRESSURE   50FLOW RATE
(GPM)
4.7L 9653 kPa (1900 psi)1100 RPM 2.4-2.8
GPM Minium
@ 200 psi
DIAGNOSIS AND TESTING - 4.7L -
HYDRAULIC
The following procedures are used to test the oper-
ation of the power steering and hydraulic fan sys-
tems on the vehicle. This test will provide the gallons
per minute (GPM) or flow rate of the power steering
pump along with any maximum relief pressure. Per-
form test anytime a power steering system problem
is present. This test will determine if the power
steering pump, hydraulic fan, and power steering
gear are not functioning properly. It will also deter-
mine if the flow coming out of the hydraulic fan
motor is sufficient for the power steering gear. The
following pressure and flow test is performed using
the Power Steering Analyzer Tool kit 6815 (Fig. 2)
and Adapter kit 8630 (Fig. 3).
FLOW TEST - FLOW FROM POWER STEERING
PUMP
(1) Check the power steering belt to ensure it is in
good condition and adjusted properly.
(2) Connect the pressure gauge hose from the
Power Steering Analyzer to Tube 8630-2.
(3) Connect Adapter 8630-3 to Power Steering
Analyzer test valve end.
(4) Disconnect the high pressure hose from the
power steering pump.
(5) Connect Tube 8630-2 to the pump hose fitting.
(6) Connect the power steering hose from the fan
motor to Adapter 8630-3.
(7) Open the test valve completely.
(8) Start engine and let idle long enough to circu-
late power steering fluid through the flow/pressure
test gauge.
(9) Shut off the engine and check the fluid level,
add fluid ass necessary. Start engine again and let
idle.
(10) The initial pressure reading should be 483 -
690 kPa (70 - 100 psi). If pressure is higher inspect
the hoses for restrictions and repair as necessary.
Fig. 3 4.7L HYDRAULIC POWER STEERING TEST
ADAPTERS
WJSTEERING 19 - 5
STEERING (Continued)