
(6)Open fuel fill door and remove screws mounting
fuel filler tube assembly to body. Do not disconnect
rubber fuel fill or vent hoses from tank at this time.
(7) Place a transmission jack under center of fuel
tank. Apply a slight amount of pressure to fuel tank
with transmission jack.
(8) Remove fuel tank mounting strap nuts from
mounting strap studs (Fig. 35). If equipped, remove
fuel tank shield bolts.
(9) Lower fuel tank only enough to allow access to
top of tank. The 2 tank fittings (where rubber fuel fill
and vent hose connections are made) must be posi-
tioned above tank level. Rotate tank slightly to allow
these fittings to be above tank level.
WARNING: WRAP SHOP TOWELS AROUND HOSES
TO CATCH ANY GASOLINE SPILLAGE.
(10) While working over left rear tire/wheel, dis-
connect rubber fuel vent hose at fuel tank (Fig. 35)
(vent hose is the smallest of 2 hoses). Position fuel
siphoning/drain hose into this fitting at tank. Drain
fuel into an approved portable holding tank or a
properly labeled gasoline (or diesel fuel) safety con-
tainer.
(11) Disconnect rubber fuel fill hose at fuel tank
(Fig. 35).
(12)Gas Powered Engines:
(a) While working over left rear tire/wheel, dis-
connect wiring harness connector from electrical
connector at top of fuel pump module (Fig. 36) or
(Fig. 37).
(b) If equipped with 26 or 34 gallon fuel tank,
two EVAP lines are connected to rollover valves.
Disconnect EVAP line from rollover valve at top of
module (Fig. 36). Disconnect other EVAP line from
rollover valve near rear of tank (Fig. 36).
(c) If equipped with 35 gallon fuel tank, two
EVAP lines are connected to rollover valves. Dis-
connect EVAP lines from rollover valves at top-
front and top-rear of fuel tank (Fig. 38).
(d) Disconnect fuel supply line at fuel filter/fuel
pressure regulator supply fitting (Fig. 36) or (Fig.
37). Refer to Quick-Connect Fittings for proce-
dures.
(13)Diesel Powered Engines:
(a) While working over left rear tire/wheel, dis-
connect wiring harness connector from electrical
connector at top of fuel tank module (Fig. 39).
(b) Disconnect fuel supply and fuel return lines
at the fuel tank module fittings (Fig. 39). Refer to
Quick-Connect Fittings for procedures.
(14) Gasoline Engines: If fuel pump module
removal is necessary, refer to Fuel Pump Module
Removal/Installation in this group. Diesel Engines: If
fuel tank module removal is necessary, refer to Fuel
Tank Module Removal/Installation in this group.
INSTALLATION
(1) Gasoline Engines: If fuel pump module is being
installed, refer to Fuel Pump Module Removal/Instal-
lation in this group. Diesel Engines: If fuel tank mod-
ule is being installed, refer to Fuel Tank Module
Removal/Installation in this group.
(2) Place fuel tank on top of transmission jack.
(3) Install rubber fill and vent lines to tank.
Tighten hose clamps to 2.3 N´m (20 in. lbs.) torque.
(4) Raise tank into position while guiding fill and
vent hoses to body. Raise tank only enough to allow
access to top of tank.
(5)Gas Powered Engines:
(a) Connect electrical connector to fuel pump
module.
(b) Connect EVAP hoses at rollover valves.
(c) Connect fuel supply line at fuel filter/fuel
pressure regulator. Refer to Quick-Connect Fittings
for procedures.
(6)Diesel Powered Engines:
(a) Connect electrical connector to fuel tank
module.
Fig. 35 Fuel Tank MountingÐTypical
1 - STRAP MOUNTING STUDS (AT FRAME)
2 - FUEL FILL HOSE
3 - FUEL VENT HOSE
4 - STRAP MOUNTING NUTS (2)
5 - FUEL TANK STRAPS (2)
6 - FUEL TANK
7 - CLAMPS
14 - 20 FUEL DELIVERY - GASOLINEBR/BE
FUEL TANK (Continued)

(7) Connect two mounting straps and mounting
strap nuts.
(8) Tighten strap nuts to 41 N´m (30 ft. lbs.)
torque. Do not over tighten retaining strap nuts.
(9) Remove transmission jack.
(10) Connect fuel filler tube assembly to body.
(11) If equipped, connect grounding wire (strap)
and screw.
(12) Refill fuel tank and inspect all hoses and lines
for leaks.
(13)
Connect negative battery cable(s) to battery(s).
INLET FILTER
REMOVAL
The fuel pump inlet filter (strainer) is located on
the bottom of the fuel pump module (Fig. 40). The
fuel pump module is located inside of fuel tank.
(1) Remove fuel tank. Refer to Fuel Tank Removal/
Installation.
(2) Remove fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Remove filter by carefully prying 2 lock tabs at
bottom of module with 2 screwdrivers. Filter is
snapped to module.
(4) Clean bottom of pump module.
INSTALLATION
The fuel pump inlet filter (strainer) is located on
the bottom of the fuel pump module (Fig. 40). The
fuel pump module is located inside of fuel tank.
(1) Snap new filter to bottom of module. Be sure
o-ring is in correct position.(2) Install fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
QUICK CONNECT FITTING
DESCRIPTION
Different types of quick-connect fittings are used to
attach various fuel system components, lines and
tubes. These are: a single-tab type, a two-tab type or
a plastic retainer ring type. Some are equipped with
safety latch clips. Some may require the use of a spe-
cial tool for disconnection and removal. Refer to
Quick-Connect Fittings Removal/Installation for more
information.
CAUTION: The interior components (o-rings, clips)
of quick-connect fittings are not serviced sepa-
rately, but new plastic spacers are available for
some types. If service parts are not available, do
not attempt to repair the damaged fitting or fuel line
(tube). If repair is necessary, replace the complete
fuel line (tube) assembly.
STANDARD PROCEDURES - QUICK-CONNECT
FITTINGS
Also refer to Fuel Tubes/Lines/Hoses and Clamps.
Different types of quick-connect fittings are used to
attach various fuel system components, lines and
tubes. These are: a single-tab type, a two-tab type or
a plastic retainer ring type. Safety latch clips are
used on certain components/lines. Certain fittings
may require use of a special tool for disconnection.
DISCONNECTING
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSE,
FITTING OR LINE, FUEL SYSTEM PRESSURE MUST
BE RELEASED. REFER TO FUEL SYSTEM PRES-
SURE RELEASE PROCEDURE.
CAUTION: The interior components (o-rings, spac-
ers) of some types of quick-connect fitting are not
serviced separately. If service parts are not avail-
able, do not attempt to repair a damaged fitting or
fuel line. If repair is necessary, replace complete
fuel line assembly.
(1) Perform fuel pressure release procedure. Refer
to Fuel Pressure Release Procedure.
(2) Disconnect negative battery cable from battery.
Fig. 40 Fuel Pump Inlet Filter
1 - FUEL PUMP INLET FILTER
2 - LOCK TABS (2)
3 - FUEL PUMP MODULE (BOTTOM)
14 - 22 FUEL DELIVERY - GASOLINEBR/BE
FUEL TANK (Continued)

(23) Inspect for exhaust system restrictions such
as pinched exhaust pipes, collapsed muffler or
plugged catalytic convertor.
(24) If equipped with automatic transmission, ver-
ify that electrical harness is firmly connected to park/
neutral switch. Refer to 21, Automatic Transmission.
(25) Verify electrical harness is firmly connected to
rear wheel speed sensor. Verify rear wheel speed sen-sor is firmly attached to rear axle with proper air
gap. Refer to 5, Brakes for information.
(26) If equipped with 4±wheel antilock brake sys-
tem, verify electrical harness is firmly connected to
each front wheel speed sensor. Verify both front
wheel speed sensors are firmly attached. Refer to 5,
Brakes for information.
(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.
(30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and
clean. Inspect for chaffed wires or wires rubbing up
against other components.
Fig. 8 Engine Coolant Temperature
1 - GENERATOR
2 - A/C COMPRESSOR
3 - ENGINE COOLANT TEMPERATURE SENSOR
4 - ELEC. CONN.
Fig. 9 Left/Right Oxygen SensorsÐHDC Engines
1 - DUAL OXYGEN SENSORS
2 - TOP OF TRANSMISSION
Fig. 10 Pre-Catalyst/Post-Catalyst Sensors
1 - POST CATALYST OXYGEN SENSOR (1/3)
2 - PRE-CATALYST OXYGEN SENSOR (1/2)
Fig. 11 Oxygen Sensors
BR/BEFUEL INJECTION - GASOLINE 14 - 31
FUEL INJECTION - GASOLINE (Continued)

(25) Verify electrical harness is firmly connected to
rear wheel speed sensor. Verify rear wheel speed sen-
sor is firmly attached to rear axle with proper air
gap. Refer to 5, Brakes for information.
(26) If equipped with 4±wheel antilock brake sys-
tem, verify electrical harness is firmly connected to
each front wheel speed sensor. Verify both front
wheel speed sensors are firmly attached. Refer to 5,
Brakes for information.
(27) Verify that fuel pump/gauge sender unit wire
connector is firmly connected to harness connector.
(28) Inspect fuel hoses at fuel pump/gauge sender
unit for cracks or leaks.
(29) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.
(30) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight and
clean. Inspect for chaffed wires or wires rubbing up
against other components.
Fig. 18 Upstream/Downstream Oxygen Sensors
1 - DOWN STREAM OXYGEN SENSOR (1/2)
2 - UP STREAM OXYGEN SENSOR (1/1)
Fig. 19 Left/Right
1 - DUAL OXYGEN SENSORS
2 - TOP OF TRANSMISSION
Fig. 20 Pre-Catalyst/Post Catalyst Oxygen Sensors
1 - POST CATALYST OXYGEN SENSOR (1/3)
2 - PRE-CATALYST OXYGEN SENSOR (1/2)
14 - 34 FUEL INJECTION - GASOLINEBR/BE
FUEL INJECTION - GASOLINE (Continued)

SPECIFICATIONS
SPECIFICATIONS - TORQUE - GAS FUEL INJECTION
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Air Cleaner Housing
Mount. NutsÐ8.0L Engine11 9 6
Air Cleaner Housing Metal
ClampÐ3.9L/5.2L/5.9L
Engines435
Crankshaft Position
Sensor Mounting
BoltsÐAll Engines870
Camshaft Position Sensor
MountingÐ8.0L Engine650
Engine Coolant
Temperature SensorÐAll
Engines6-8 55-75
Fuel Tank Mounting Nuts 41 30
Fuel Hose Clamps 1 10
IAC Motor-To-Throttle
Body Bolts760
Intake Manifold Air Temp.
SensorÐAll Engines12-15 110-130
MAP Sensor Mounting
ScrewsÐ3.9L/5.2L/5.9L
Engines325
MAP Sensor Mounting
ScrewsÐ8.0L Engine220
Oxygen SensorÐAll
Engines30 22
Powertrain Control Module
Mounting Screws435
Throttle Body Mounting
BoltsÐ3.9L/5.2L/5.9L
Engines23 200
Throttle Body Mounting
BoltsÐ8.0L Engine22 192
Throttle Position Sensor
Mounting ScrewsÐAll
Engines760
BR/BEFUEL INJECTION - GASOLINE 14 - 35
FUEL INJECTION - GASOLINE (Continued)

REMOVAL - 8.0L
The crankshaft position sensor is located on the
right-lower side of the cylinder block, forward of the
right engine mount, just above the oil pan rail (Fig.
28).
(1) Raise and support vehicle.
(2) Disconnect sensor pigtail harness from main
engine wiring harness.
(3) Remove sensor mounting bolt (Fig. 29).
(4) Cut plastic tie strap (Fig. 28) securing sensor
pigtail harness to side of engine block.
(5) Carefully pry sensor from cylinder block in a
rocking action with two small screwdrivers.
(6) Remove sensor from vehicle.
(7) Check condition of sensor o-ring (Fig. 30).
INSTALLATION - 3.9L/5.2L/5.9L
(1) Position crankshaft position sensor to engine.
(2) Install mounting bolts and tighten to 8 N´m (70
in. lbs.) torque.
(3) Connect main harness electrical connector to
sensor.
(4) Install air cleaner tube.
INSTALLATION - 8.0L
The crankshaft position sensor is located on the
right-lower side of the cylinder block, forward of the
right engine mount, just above the oil pan rail (Fig.
28).(1) Apply a small amount of engine oil to sensor
o-ring (Fig. 30).
(2) Install sensor into cylinder block with a slight
rocking action. Do not twist sensor into position as
damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder block
(Fig. 29). If sensor is not flush, damage to sensor
mounting tang may result.
(3) Install mounting bolt and tighten to 8 N´m (70
in. lbs.) torque.
(4) Connect sensor pigtail harness to main engine
wiring harness
Fig. 28 Crankshaft Position Sensor LocationÐ8.0L
V-10 Engine
1 - CRANKSHAFT POSITION SENSOR
2 - HOLE
3 - OIL FILTER
4 - PLASTIC TIE STRAP
5 - PIGTAIL HARNESS
Fig. 29 Sensor Removal/InstallationÐ8.0L V-10
Engine
1 - CRANKSHAFT POSITION SENSOR
2 - MOUNTING BOLT
3 - SENSOR POSITIONED FLUSH TO CYLINDER BLOCK
Fig. 30 Sensor O-RingÐ8.0L V-10 Engine
1 - CRANKSHAFT POSITION SENSOR O-RING
2 - ELECTRICAL CONNECTOR
3 - PIGTAIL HARNESS
14 - 40 FUEL INJECTION - GASOLINEBR/BE
CRANKSHAFT POSITION SENSOR (Continued)

(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 assembly.
INSTALLATION - 8.0L
The IAC motor is located on the back of the throt-
tle body (Fig. 33).
(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 housing to throttle body.
(5) Install 4 air cleaner housing mounting nuts.
Tighten nuts to 11 N´m (96 in. lbs.) torque.
(6) Install air cleaner housing cover.
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION - 3.9L/5.2L/5.9L/8.0L
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 - 3.9L/5.2L/5.9L/8.0L
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 - 3.9L/5.2L/5.9L
The intake manifold air temperature sensor is
located in the front/side of the intake manifold (Fig.
34).
(1) Remove air cleaner assembly.
(2) Disconnect electrical connector at sensor (Fig.
34).
(3) Remove sensor from intake manifold.
REMOVAL - 8.0L
The intake manifold air temperature sensor is
located in the side of the intake manifold near the
front of throttle body (Fig. 35).
(1) Disconnect electrical connector at sensor.
(2) Remove sensor from intake manifold.
INSTALLATION - 3.9L/5.2L/5.9L
The intake manifold air temperature sensor is
located in the front/side of the intake manifold (Fig.
34).
Fig. 34 Air Temperature SensorÐ3.9L/5.2L/5.9L
1 - INTAKE MANIFOLD AIR TEMPERATURE SENSOR
2 - ELECTRICAL CONNECTOR
Fig. 35 Air Temperature SensorÐ8.0L Engine
1 - INTAKE MANIFOLD AIR TEMP. SENSOR
2 - INTAKE MANIFOLD
BR/BEFUEL INJECTION - GASOLINE 14 - 43
IDLE AIR CONTROL MOTOR (Continued)

(1) Install sensor to intake manifold. Tighten to
12±15 N´m (110±130 in. lbs.) torque.
(2) Install electrical connector.
(3) Install air cleaner.
INSTALLATION - 8.0L
The intake manifold air temperature sensor is
located in the side of the intake manifold near the
front of throttle body (Fig. 35).
(1) Install sensor to intake manifold. Tighten to
12±15 N´m (110±130 in. lbs.) torque.
(2) Install electrical connector.
MANIFOLD ABSOLUTE
PRESSURE SENSOR
DESCRIPTION - 3.9L/5.2L/5.9L/8.0L
On 3.9L/5.2L/5.9L engines, the MAP sensor is
mounted on the side of the engine throttle body. The
sensor is connected to the throttle body with a rubber
L-shaped fitting.
On the 8.0L 10±cylinder engine, the MAP sensor is
mounted into the right side of the intake manifold.
OPERATION - 3.9L/5.2L/5.9L/8.0L
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 voltageagain, 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 a
very 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.
14 - 44 FUEL INJECTION - GASOLINEBR/BE
INTAKE AIR TEMPERATURE SENSOR (Continued)