check oil JEEP GRAND CHEROKEE 2002 WJ / 2.G Owners Manual

OIL PUMP
REMOVAL
(1) Remove the oil pan and pick-up tube (Refer to
9 - ENGINE/LUBRICATION/OIL PAN - REMOVAL).
(2) Remove the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(3) Remove the timing chains and tensioners
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
(4) Remove the four bolts, primary timing chain
tensioner and the oil pump.
DISASSEMBLY
(1) Remove oil pump cover screws and lift off cover
plate.
(2) Remove pump inner and outer rotors.
NOTE: Once the oil pressure relief valve, cup plug,
and pin are removed, the pump assembly must be
replaced.
(3) If it is necessary to remove the pressure relief
valve, drive the roll pin from pump housing and
remove cup plug, spring and valve.
CLEANING
(1) Wash all parts in a suitable solvent.
INSPECTION
CAUTION: Oil pump pressure relief valve and
spring should not be removed from the oil pump. If
these components are disassembled and or
removed from the pump the entire oil pump assem-
bly must be replaced.
(1) Clean all parts thoroughly. Mating surface of
the oil pump housing should be smooth. If the pump
cover is scratched or grooved the oil pump assembly
should be replaced.
(2) Lay a straight edge across the pump cover sur-
face (Fig. 97). If a 0.025 mm (0.001 in.) feeler gauge
can be inserted between the cover and the straight
edge the oil pump assembly should be replaced.
(3) Measure the thickness of the outer rotor (Fig.
98). If the outer rotor thickness measures at 12.005
mm (0.472 in.) or less the oil pump assembly must be
replaced.(4) Measure the diameter of the outer rotor. If the
outer rotor diameter measures at 85.925 mm (3.382
in.) or less the oil pump assembly must be replaced.
(5) Measure the thickness of the inner rotor (Fig.
99). If the inner rotor thickness measures at 12.005
mm (0.472 in.) or less then the oil pump assembly
must be replaced.
(6) Slide outer rotor into the body of the oil pump.
Press the outer rotor to one side of the oil pump body
and measure clearance between the outer rotor and
the body (Fig. 100). If the measurement is 0.235mm
(0.009 in.) or more the oil pump assembly must be
replaced.
(7) Install the inner rotor in the into the oil pump
body. Measure the clearance between the inner and
outer rotors (Fig. 101). If the clearance between the
rotors is .150 mm (0.006 in.) or more the oil pump
assembly must be replaced.
(8) Place a straight edge across the body of the oil
pump (between the bolt holes), if a feeler gauge of
.095 mm (0.0038 in.) or greater can be inserted
between the straightedge and the rotors, the pump
must be replaced (Fig. 102).
NOTE: The 4.7 Oil pump is released as an assem-
bly. There are no DaimlerChrysler part numbers for
Sub-Assembly components. In the event the oil
pump is not functioning or out of specification it
must be replaced as an assembly.
Fig. 97 Checking Oil Pump Cover Flatness
1 - STRAIGHT EDGE
2 - FEELER GAUGE
3 - OIL PUMP COVER
9 - 134 ENGINE - 4.7LWJ

(7) Connect throttle cable and speed control cable
to throttle body.
(8) Install fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL RAIL - INSTALLATION).
(9) Install ignition coil towers (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/IGNITION COIL -
INSTALLATION).
(10) Install coolant temperature sensor (Refer to 7
- COOLING/ENGINE/ENGINE COOLANT TEMP
SENSOR - INSTALLATION).
(11) Connect electrical connectors for the following
components:
²Manifold Absolute Pressure (MAP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Coolant Temperature (CTS) Sensor
²Idle Air Control (IAC) Motor
²Ignition coil towers
²Fuel injectors
(12) Install top oil dipstick tube retaining bolt and
ground strap.
(13) Install right side engine lifting stud.
(14) Install generator including electrical connec-
tions (Refer to 8 - ELECTRICAL/CHARGING/GEN-
ERATOR - INSTALLATION).
(15) Connect Vapor purge hose, Brake booster
hose, Speed control servo hose, Positive crankcase
ventilation (PCV) hose.
(16) Install air conditioning compressor including
electrical connections.
(17) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(18) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(19) Install cowl to hood seal (Refer to 23 - BODY/
WEATHERSTRIP/SEALS/COWL WEATHERSTRIP -
INSTALLATION).
(20) Install air cleaner housing and throttle body
resonator. Tighten resonator bolts 4.5 N´m (40 in.
lbs.).
(21) Connect negative cable to battery.
EXHAUST MANIFOLD - LEFT
DESCRIPTION
The exhaust manifolds are log style with a pat-
ented flow enhancing design to maximize perfor-
mance. The exhaust manifolds are made of high
silicon molybdenum cast iron. A perforated core
graphite exhaust manifold gasket is used to improve
sealing to the cylinder head. The exhaust manifolds
are covered by a three layer laminated heat shield
for thermal protection and noise reduction. The heat
shields are fastened with a torque prevailing nutthat is backed off slightly to allow for the thermal
expansion of the exhaust manifold.
REMOVAL
(1) Disconnect negative cable for battery.
(2) Hoist vehicle.
(3) Disconnect exhaust pipe at manifold.
(4) Lower vehicle.
(5) Remove air cleaner housing and tube.
(6) Remove the front two exhaust heat shield
retaining fasteners. Raise vehicle and remove the
fasteners at rear of heat shield.
(7) Remove heat shield (Fig. 107).
(8) Lower vehicle and remove the upper exhaust
manifold retaining bolts (Fig. 107).
(9) Raise vehicle and remove the lower exhaust
manifold retaining bolts (Fig. 107).
(10) Remove exhaust manifold and gasket (Fig.
107). Manifold is removed from below the engine
compartment.
CLEANING
(1) Clean the exhaust manifold using a suitable
cleaning solvent, then allow to air dry.
(2) Clean all gasket residue from the manifold
mating surface.
INSPECTION
(1) Inspect the exhaust manifold for cracks in the
mating surface and at every mounting bolt hole.
(2) Using a straight edge and a feeler gauge, check
the mating surface for warp and twist.
(3) Inspect the manifold to exhaust pipe mating
surface for cracks, gouges, or other damage that
would prevent sealing.
INSTALLATION
(1) Install exhaust manifold and gasket from below
engine compartment.
(2) Install lower exhaust manifold fasteners (Fig.
107). DO NOT tighten until all fasteners are in
place.
(3) Lower vehicle and install upper exhaust mani-
fold fasteners (Fig. 107). Tighten all manifold bolts
starting at center and working outward to 25 N´m
(18 ft. lbs.).
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(4) Install exhaust manifold heat shield (Fig. 107).
Tighten fasteners to 8 N´m (72 in. lbs.), then loosen
45 degrees.
(5) Install air cleaner housing and tube.
(6) Connect exhaust pipe to manifold.
(7) Connect negative cable to battery.
9 - 138 ENGINE - 4.7LWJ
INTAKE MANIFOLD (Continued)

INSPECTION
(1) Inspect the exhaust manifold for cracks in the
mating surface and at every mounting bolt hole.
(2) Using a straight edge and a feeler gauge, check
the mating surface for warp and twist.
(3) Inspect the manifold to exhaust pipe mating
surface for cracks, gouges, or other damage that
would prevent sealing.
INSTALLATION
(1) Install exhaust manifold and gasket from below
engine compartment.
(2) Install lower exhaust manifold fasteners. DO
NOT tighten until all fasteners are in place.
(3) Lower vehicle and install upper exhaust mani-
fold fasteners. Tighten all manifold bolts starting at
center and working outward to 25 N´m (18 ft. lbs.).
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(4) Install exhaust manifold heat shield. Tighten
fasteners to 8 N´m (72 in. lbs.), then loosen 45
degrees.
(5) Install starter and fasteners.
(6) Connect exhaust pipe to manifold.
(7) Connect heater hoses at engine.
(8) Install fastener attaching A/C accumulator.
(9) Install A/C compressor and fasteners.
(10) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(11) Install washer bottle and battery tray assem-
bly.
(12) Install PDC.
(13) Install battery and connect cables.
(14) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
VALVE TIMING
DESCRIPTION - TIMING DRIVE SYSTEM
The timing drive system has been designed to pro-
vide quiet performance and reliability to support a
non-free wheelingengine. Specifically the intake
valves are non-free wheeling and can be easily dam-
aged with forceful engine rotation if camshaft-to-
crankshaft timing is incorrect. The timing drive
system consists of a primary chain and two second-
ary timing chain drives (Fig. 109).
OPERATION - TIMING DRIVE SYSTEM
The primary timing chain is a single inverted tooth
type. The primary chain drives the large fifty tooth
idler sprocket directly from a 25 tooth crankshaftsprocket. Primary chain motion is controlled by a
pivoting leaf spring tensioner arm and a fixed guide.
The arm and the guide both use nylon plastic wear
faces for low friction and long wear. The primary
chain receives oil splash lubrication from the second-
ary chain drive and oil pump leakage. The idler
sprocket assembly connects the primary and second-
ary chain drives. The idler sprocket assembly con-
sists of two integral thirty tooth sprockets and a fifty
tooth sprocket that is splined to the assembly. The
spline joint is a non ± serviceable press fit anti rattle
type. A spiral ring is installed on the outboard side of
the fifty tooth sprocket to prevent spline disengage-
ment. The idler sprocket assembly spins on a station-
ary idler shaft. The idler shaft is press-fit into the
cylinder block. A large washer on the idler shaft bolt
and the rear flange of the idler shaft are used to con-
trol sprocket thrust movement. Pressurized oil is
routed through the center of the idler shaft to pro-
vide lubrication for the two bushings used in the
idler sprocket assembly.
There are two secondary drive chains, both are
inverted tooth type, one to drive the camshaft in each
SOHC cylinder head. There are no shaft speed
changes in the secondary chain drive system. Each
secondary chain drives a thirty tooth cam sprocket
directly from the thirty tooth sprocket on the idler
sprocket assembly. A fixed chain guide and a hydrau-
lic oil damped tensioner are used to maintain tension
in each secondary chain system. The hydraulic ten-
sioners for the secondary chain systems are fed pres-
surized oil from oil reservoir pockets in the block.
Each tensioner also has a mechanical ratchet system
that limits chain slack if the tensioner piston bleeds
down after engine shut down. The tensioner arms
and guides also utilize nylon wear faces for low fric-
tion and long wear. The secondary timing chains
receive lubrication from a small orifice in the ten-
sioners. This orifice is protected from clogging by a
fine mesh screen which is located on the back of the
hydraulic tensioners.
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE TIMING -
VERIFICATION
CAUTION: The 4.7L is a non free-wheeling design
engine. Therefore, correct engine timing is critical.
NOTE: Components referred to as left hand or right
hand are as viewed from the drivers position inside
the vehicle.
WJENGINE - 4.7L 9 - 141
EXHAUST MANIFOLD - RIGHT (Continued)

(13) Remove Special Tool 8515, then attach both
sprockets to camshafts. Remove excess oil from bolts,
then Install sprocket bolts, but do not tighten at this
time.
(14) Verify that all plated links are aligned with
the marks on all sprockets and the ªV8º marks on
camshaft sprockets are at the 12 o'clock position (Fig.
127).
CAUTION: Ensure the plate between the left sec-
ondary chain tensioner and block is correctly
installed.
(15) Install both secondary chain tensioners.
Tighten bolts to 28 N´m (250 in. lbs.).
NOTE: Left and right secondary chain tensioners
are not common.
(16) Before installing idler sprocket bolt, lubricate
washer with oil, and tighten idler sprocket assembly
retaining bolt to 34 N´m (25 ft. lbs.).
(17) Remove all locking pins (3) from tensioners.
CAUTION: After pulling locking pins out of each
tensioner, DO NOT manually extend the tensioner(s)
ratchet. Doing so will over tension the chains,
resulting in noise and/or high timing chain loads.
(18) Using Special Tool 6958, Spanner with Adap-
tor Pins 8346, tighten left (Fig. 131) and right (Fig.
132). camshaft sprocket bolts to 122 N´m (90 ft. lbs.).
(19) Rotate engine two full revolutions. Verify tim-
ing marks are at the follow locations:
²primary chain idler sprocket dot is at 12 o'clock
(Fig. 127)
²primary chain crankshaft sprocket dot is at 6
o'clock (Fig. 127)
²secondary chain camshaft sprockets ªV8º marks
are at 12 o'clock (Fig. 127)(20) Lubricate all three chains with engine oil.
(21) After installing all chains, it is recommended
that the idler gear end play be checked (Fig. 133).
The end play must be within 0.10±0.25 mm (0.004±
0.010 in.). If not within specification, the idler gear
must be replaced.
Fig. 131 Tightening Left Side Camshaft Sprocket
Bolt
1 - TORQUE WRENCH
2 - CAMSHAFT SPROCKET
3 - LEFT CYLINDER HEAD
4 - SPECIAL TOOL 6958 SPANNER WITH ADAPTER PINS 8346
9 - 152 ENGINE - 4.7LWJ
TIMING BELT/CHAIN AND SPROCKETS (Continued)

(3) Apply a small amount of clean engine oil to
o-rings.
(4) Position filter/regulator to body and install 2
bolts. Tighten bolts to 3 N´m (30 in. lbs.) torque.
(5) Connect 3 fittings. Refer to Quick-Connect Fit-
tings.
(6) Connect negative battery cable to battery.
(7) Start engine and check for leaks.
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel pump module has 4 different circuits
(wires). Two of these circuits are used for the fuel
gauge sending unit for fuel gauge operation, and for
certain OBD II emission requirements. The other 2
wires are used for electric fuel pump operation.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Powertrain
Control Module (PCM).NOTE: For diagnostic pur-
poses, this 12V power source can only be veri-fied with the circuit opened (fuel pump module
electrical connector unplugged). With the con-
nectors plugged, output voltages will vary from
about 0.6 volts at FULL, to about 8.6 volts at
EMPTY (about 8.6 volts at EMPTY for Jeep
models, and about 7.0 volts at EMPTY for
Dodge Truck models).The resistor track is used to
vary the voltage (resistance) depending on fuel tank
float level. As fuel level increases, the float and arm
move up, which decreases voltage. As fuel level
decreases, the float and arm move down, which
increases voltage. The varied voltage signal is
returned back to the PCM through the sensor return
circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the PCM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the PCM, the PCM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
For OBD II Emission Monitor Requirements:
The PCM will monitor the voltage output sent from
the resistor track on the sending unit to indicate fuel
level. The purpose of this feature is to prevent the
OBD II system from recording/setting false misfire
and fuel system monitor diagnostic trouble codes.
The feature is activated if the fuel level in the tank
is less than approximately 15 percent of its rated
capacity. If equipped with a Leak Detection Pump
(EVAP system monitor), this feature will also be acti-
vated if the fuel level in the tank is more than
approximately 85 percent of its rated capacity.
DIAGNOSIS AND TESTING - FUEL LEVEL
SENDING UNIT
The fuel level sending unit contains a variable
resistor (track). As the float moves up or down, elec-
trical resistance will change. Refer to Instrument
Panel and Gauges for Fuel Gauge testing. To test the
gauge sending unit only, it must be removed from
vehicle. The unit is part of the fuel pump module.
Refer to Fuel Pump Module Removal/Installation for
procedures. Measure the resistance across the send-
ing unit terminals. With float in up position, resis-
tance should be 20 ohms (+/- 5%). With float in down
position, resistance should be 270 ohms (+/- 5%).
REMOVAL
The fuel gauge sending unit (fuel level sensor) and
float assembly is located on the side of fuel pump
module (Fig. 6). The fuel pump module is located
within the fuel tank.
Fig. 5 Fuel Filter/Fuel Pressure Regulator Removal/
Installation
1 - FUEL FILTER/FUEL PRESSURE REGULATOR
2 - MOUNTING BOLTS (2)
WJFUEL DELIVERY 14 - 7
FUEL FILTER/PRESSURE REGULATOR (Continued)

(19) Disconnect test leads from relay cavities
immediately after testing.
FUEL PUMP PRESSURE TEST
Use this test in conjunction with other fuel system
tests. Refer to the Fuel Pump Capacity Test, Fuel
Pressure Leak Down Test and Fuel Pump Amperage
Test.
Check Valve Operation:The electric fuel pump
outlet contains a one-way check valve to prevent fuel
flow back into the tank and to maintain fuel supply
line pressure (engine warm) when pump is not oper-
ational. It is also used to keep the fuel supply line
full of gasoline when pump is not operational. After
the vehicle has cooled down, fuel pressure may drop
to 0 psi (cold fluid contracts), but liquid gasoline will
remain in fuel supply line between the check valve
and fuel injectors.Fuel pressure that has
dropped to 0 psi on a cooled down vehicle
(engine off) is a normal condition.When the elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
The fuel system is equipped with a combination
fuel filter/fuel pressure regulator. The fuel pressure
regulator is not controlled by engine vacuum.
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE EVEN WITH THE ENGINE
OFF. BEFORE DISCONNECTING FUEL LINE AT
FUEL RAIL, THIS PRESSURE MUST BE RELEASED.REFER TO THE FUEL SYSTEM PRESSURE
RELEASE PROCEDURE.
(1) Remove pressure test port cap at fuel rail test
port (Fig. 12) or (Fig. 13) . Connect 0±414 kPa (0-60
psi) fuel pressure gauge (from gauge set 5069) to test
port pressure fitting on fuel rail (Fig. 14) .The DRB
III Scan Tool along with the PEP module, the
500 psi pressure transducer, and the transduc-
er-to-test port adapter may also be used in
place of the fuel pressure gauge.
(2) Start and warm engine and note pressure
gauge reading. The DRB scan tool may also be used
to power fuel pump. Fuel pressure should be 339 kPa
  34 kPa (49.2 psi   5 psi) at idle.
(3) If engine runs, but pressure is below 44.2 psi,
determine if fuel pump or filter/regulator is defective.
Proceed to next step:
(a) Check for a kinked fuel supply line some-
where between fuel rail and fuel pump module.
Fig. 11 FUEL PUMP RELAY - TYPE 3
TERMINAL LEGEND
NUMBER IDENTIFICATION
1 COIL BATTERY
2 COIL GROUND
3 COMMON FEED
4 NORMALLY CLOSED
5 NORMALLY OPEN
Fig. 12 Test Port Cap LocationÐ4.0L Engine
1 - INJ. #1
2 - INJ. #2
3 - INJ. #3
4 - INJ. #4
5 - INJ. #5
6 - INJ. #6
7 - FUEL INJECTOR RAIL
8 - FUEL DAMPER
9 - PRESSURE TEST PORT CAP
10 - MOUNTING BOLTS (4)
11 - QUICK-CONNECT FITTING
WJFUEL DELIVERY 14 - 11
FUEL PUMP (Continued)

(9) Disconnect speed control cable at throttle body
(if equipped). Refer to Speed Control Cable.
(10) Disconnect automatic transmission cable at
throttle body (if equipped).
(11) Remove cable routing bracket at intake mani-
fold.
(12) Clean dirt/debris from each fuel injector at
intake manifold.
(13) Remove fuel rail mounting nuts/bolts (Fig.
24).
(14) Remove fuel rail by gently rocking until all
fuel injectors have cleared machined holes at intake
manifold.
(15) If fuel injectors are to be removed, refer to
Fuel Injector Removal/Installation.
INSTALLATION
INSTALLATION - 4.7L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Apply a small amount of engine oil to each fuel
injector o-ring. This will help in fuel rail installation.
(3) Position fuel rail/fuel injector assembly to
machined injector openings in cylinder head.
(4) Guide each injector into cylinder head. Be care-
ful not to tear injector o-rings.(5) Pushrightside of fuel rail down until fuel
injectors have bottomed on cylinder head shoulder.
Pushleftfuel rail down until injectors have bot-
tomed on cylinder head shoulder.
(6) Install 4 fuel rail mounting bolts and tighten to
27 N´m (20 ft. lbs.).
(7) Install ignition coils. Refer to Ignition Coil
Removal/Installation.
(8) Connect electrical connectors to throttle body.
(9) Connect electrical connectors to MAP and IAT
sensors.
(10) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 23). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(11) Connect vacuum lines to throttle body.
(12) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(13) Connect wiring to rear of generator.
(14) Install air box to throttle body.
(15) Install air duct to air box.
(16) Connect battery cable to battery.
(17) Start engine and check for leaks.
INSTALLATION - 4.0L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Clean each injector bore at intake manifold.
(3) Apply a small amount of clean engine oil to
each injector o-ring. This will aid in installation.
(4) Position tips of all fuel injectors into the corre-
sponding injector bore in intake manifold. Seat injec-
tors into manifold.
(5) Install and tighten fuel rail mounting bolts to
11  3 N´m (100  25 in. lbs.) torque.
(6) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 25). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(7) Connect fuel line and fuel line latch clip to fuel
rail. Refer Quick-Connect Fittings.
(8) Install protective cap to pressure test port fit-
ting (if equipped).
(9) Install cable routing bracket to intake mani-
fold.
(10) Connect throttle cable at throttle body.
(11) Connect speed control cable at throttle body (if
equipped).
(12) Connect automatic transmission cable at
throttle body (if equipped).
(13) Install oxygen sensor wiring clip nuts to fuel
rail mounting studs (certain emissions packages
only).
Fig. 25 Remove/Install Injector ConnectorÐ4.0L
Engine
14 - 18 FUEL DELIVERYWJ
FUEL RAIL (Continued)

(a) Type 1: Pry up on latch clip with a screw-
driver (Fig. 50).
(b) Type 2: Separate and unlatch 2 small arms
on end of clip (Fig. 51) and swing away from fuel
line.
(c) Slide latch clip toward fuel rail while lifting
with screwdriver.
(d) Insert special fuel line removal tool (Snap-On
number FIH 9055-1 or equivalent) into fuel line(Fig. 52). Use tool to release locking fingers in end
of line.
(e) With special tool still inserted, pull fuel line
from fuel rail.
(f) After disconnection, locking fingers will
remain within quick-connect fitting at end of fuel
line.
(10) Disconnect quick-connect fitting from fuel sys-
tem component being serviced.
CONNECTING
(1) Inspect quick-connect fitting body and fuel sys-
tem component for damage. Replace as necessary.
(2) Prior to connecting quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean parts with a lint-free cloth.
Lubricate with clean engine oil.
(3) Insert quick-connect fitting into fuel tube or
fuel system component until built-on stop on fuel
tube or component rests against back of fitting.
(4) Continue pushing until a click is felt.
(5) Single-tab type fitting: Push new tab down
until it locks into place in quick-connect fitting.
(6) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(7) Latch Clip Equipped: Install latch clip (snaps
into position).If latch clip will not fit, this indi-
cates fuel line is not properly installed to fuel
rail (or other fuel line). Recheck fuel line con-
nection.
(8) Connect negative cable to battery.
(9) Start engine and check for leaks.
Fig. 50 LATCH CLIP-TYPE 1
1 - TETHER STRAP
2 - FUEL LINE
3 - SCREWDRIVER
4 - LATCH CLIP
5 - FUEL RAIL
Fig. 51 LATCH CLIP-TYPE 2
1 - LATCH CLIP
Fig. 52 FUEL LINE DISCONNECTION USING
SPECIAL TOOL
1 - SPECIAL FUEL LINE TOOL
2 - FUEL LINE
3 - FUEL RAIL
14 - 30 FUEL DELIVERYWJ
QUICK CONNECT FITTING (Continued)

FUEL INJECTION
DIAGNOSIS AND TESTING
VISUAL INSPECTION
A visual inspection for loose, disconnected or incor-
rectly routed wires, vacuum lines and hoses should
be made. This should be done before attempting to
diagnose or service the fuel injection system. A visual
check will help spot these faults and save unneces-
sary test and diagnostic time. A thorough visual
inspection will include the following checks:
(1) Verify three 32±way electrical connectors are
fully inserted into connector of Powertrain Control
Module (PCM) (Fig. 1).
(2) Inspect battery cable connections. Be sure they
are clean and tight.
(3) Inspect fuel pump relay and air conditioning
compressor clutch relay (if equipped). Inspect ASD
and oxygen sensor heater relay connections. Inspect
starter motor relay connections. Inspect relays for
signs of physical damage and corrosion. The relays
are located in the Power Distribution Center (PDC)
(Fig. 2). Refer to label on PDC cover for relay loca-
tion.
(4) Inspect ignition coil connections (Fig. 3)or (Fig.
4).
(5) Verify camshaft position sensor wire connector
is firmly connected (Fig. 5) or (Fig. 6).
(6) Verify crankshaft position sensor wire connec-
tor is firmly connected (Fig. 7) or (Fig. 8).
Fig. 1 Powertrain Control Module (PCM) Location
1 - PCM
2 - COOLANT TANK
Fig. 2 Power Distribution Center (PDC) Location
1 - POWER DISTRIBUTION CENTER (PDC)
2 - BATTERY
Fig. 3 Ignition Coil ConnectorÐ4.0L Engine
1 - REAR OF VALVE COVER
2 - COIL RAIL
3 - COIL CONNECTOR
4 - RELEASE LOCK
5 - SLIDE TAB
14 - 32 FUEL INJECTIONWJ

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)