
Attach end of special test hose tool number 6541,
6539, 6631 or 6923 at fuel rail disconnection (tool
number will depend on model and/or engine applica-
tion). Position opposite end of this hose tool to an
approved gasoline draining station. Activate fuel
pump and drain tank until empty.
If electric fuel pump is not operating, tank must be
lowered for fuel draining. Refer to following proce-
dures.
(1) Remove fuel tank filler tube cap.
(2) Perform Fuel System Pressure Release proce-
dure as described in this group.
(3) Gasoline Engines: Disconnect negative battery
cable at battery. Diesel Engines: Disconnect both neg-
ative battery cables at both batteries.
(4) Raise vehicle on hoist.
(5) Certain models are equipped with a separate
grounding wire (strap) connecting the fuel fill tube
assembly to the body. Disconnect wire by removing
screw.
(6) Open fuel fill door and remove screws mount-
ing fuel filler tube assembly to body. Do not discon-
nect 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. 32). 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. 32)
(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. 32).
(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. 33) or
(Fig. 34).
(b) If equipped with 26 or 34 gallon fuel tank,
two EVAP lines are connected to the fuel tank
check valves. Disconnect EVAP line from check
valve at top of module (Fig. 33). Disconnect otherEVAP line from check valve near rear of tank (Fig.
33).
(c) If equipped with 35 gallon fuel tank, two
EVAP lines are connected to the fuel tank check
valves. Disconnect EVAP lines from check valves at
top-front and top-rear of fuel tank (Fig. 35).
(d) Disconnect fuel supply line at fuel filter/fuel
pressure regulator supply fitting (Fig. 33) or (Fig.
34). 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. 36).
(b) Disconnect fuel supply and fuel return lines
at the fuel tank module fittings (Fig. 36). 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.
Fig. 32 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
BR/BEFUEL DELIVERY - GASOLINE 14 - 19
FUEL TANK (Continued)

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-
Fig. 33 Fuel Pump ModuleÐGas Engine With 26 or
34 Gallon Tank
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - REAR FUEL TANK CHECK VALVE
4 - ELECTRICAL CONNECTOR
5 - FUEL PUMP MODULE
6 - FRONT FUEL TANK CHECK VALVE
7 - LOCKNUT
Fig. 34 Fuel Pump ModuleÐGas Engine With 35
Gallon Tank
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - ELECTRICAL CONNECTOR
4 - LOCKNUT
5 - FUEL PUMP MODULE
6 - AUXILIARY CAPPED FITTING
Fig. 35 Check Valve LocationsÐGas Engine With 35
Gallon Tank
1 - FRONT FUEL TANK CHECK VALVE
2 - FUEL PUMP MODULE
3 - REAR FUEL TANK CHECK VALVE
4 - FUEL TANK
Fig. 36 Fuel Tank
1 - AUXILIARY CAPPED FITTING
2 - FUEL PUMP MODULE
3 - FUEL SUPPLY/RETURN FITTINGS
4 - ELECTRICAL CONNECTOR
5 - LOCKNUT
6 - ROLLOVER VALVE
14 - 20 FUEL DELIVERY - GASOLINEBR/BE
FUEL TANK (Continued)

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.
(b) Connect fuel supply and fuel return lines to
fuel tank module fittings. Refer to Quick-Connect
Fittings in this group.
(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 bat-
tery(s).
FUEL TANK CHECK VALVE
DESCRIPTION
Diesel Powered Engine:One fuel tank check
valve is used. The check valve is located on the top of
the fuel tank module (Fig. 37). The valve may be ser-
viced separately.
Gasoline Powered Engines:If equipped with a
26 or 34 gallon fuel tank, two check valves are used.
One of the valves is permanently mounted to the top
of fuel tank (Fig. 38). If replacement of this particu-
lar valve is necessary, the fuel tank must be
replaced. The other check valve is located on the top
of the fuel pump module (Fig. 38). This valve may be
serviced separately. If replacement is necessary, refer
to the Removal/Installation section of this group.
If equipped with a 35 gallon fuel tank, two check
valves are used. Both valves are permanently
mounted to the top of fuel tank (Fig. 39). If replace-
ment is necessary, the fuel tank must be replaced.
Fig. 37 Check Valve LocationÐDiesel Powered
1 - AUXILIARY CAPPED FITTING
2 - FUEL PUMP MODULE
3 - FUEL SUPPLY/RETURN FITTINGS
4 - ELECTRICAL CONNECTOR
5 - LOCKNUT
6 - FUEL TANK CHECK VALVE
Fig. 38 Check Valve LocationsÐGas
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - REAR FUEL TANK CHECK VALVE
4 - ELECTRICAL CONNECTOR
5 - FUEL PUMP MODULE
6 - FRONT FUEL TANK CHECK VALVE
7 - LOCKNUT
BR/BEFUEL DELIVERY - GASOLINE 14 - 21
FUEL TANK (Continued)

REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE CHECK VALVE, FUEL
SYSTEM PRESSURE MUST BE RELEASED (GASO-
LINE POWERED ENGINES ONLY). REFER TO THE
FUEL PRESSURE RELEASE PROCEDURE IN
GROUP 14, FUEL SYSTEM.
(1)Diesel Powered Engine:One checkr valve is
used. The valve is located on top of fuel tank module
(Fig. 40) and may be serviced separately.
(a) Disconnect both negative battery cables at
both batteries.
(b) Remove fuel filler cap and drain fuel tank.
(c) Remove fuel tank. Refer to Fuel Tank Remov-
al/Installation in Fuel System.
(d) The check valve is seated into a rubber
grommet. Remove valve by prying one side upward
and then roll valve out of grommet.
(e) Discard old grommet.
(2)Gasoline Powered Engines:
If equipped with
a 26 or 34 gallon fuel tank, two check valves are used.
One of the valves is permanently mounted to top of
fuel tank (Fig. 41). If replacement of this particular
valve is necessary, fuel tank must be replaced. Refer
to Fuel Tank Removal/Installation in Group 14, Fuel
System. The other check valve is located on top of fuel
pump module (Fig. 41). This valve may be serviced
separately. Refer to following steps for procedures.
Fig. 39 Check Valve LocationsÐGas Powered with
35 Gallon Tank
1 - FRONT FUEL TANK CHECK VALVE
2 - FUEL PUMP MODULE
3 - REAR FUEL TANK CHECK VALVE
4 - FUEL TANK
Fig. 40 Check Valve Location - Diesel Powered
1 - AUXILIARY CAPPED FITTING
2 - FUEL PUMP MODULE
3 - FUEL SUPPLY/RETURN FITTINGS
4 - ELECTRICAL CONNECTOR
5 - LOCKNUT
6 - FUEL TANK CHECK VALVE
Fig. 41 Check Valve Locations - Gas Powered -
26/34 Gallon Tank
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - REAR FUEL TANK CHECK VALVE
4 - ELECTRICAL CONNECTOR
5 - FUEL PUMP MODULE
6 - FRONT FUEL TANK CHECK VALVE
7 - LOCKNUT
14 - 22 FUEL DELIVERY - GASOLINEBR/BE
FUEL TANK CHECK VALVE (Continued)

(8)Latch Clips:Depending on vehicle model and
engine, 2 different types of safety latch clips are used
(Fig. 50) or (Fig. 51). Type-1 is tethered to fuel line
and type-2 is not. A special tool will be necessary to
disconnect fuel line after latch clip is removed. The
latch clip may be used on certain fuel line/fuel rail
connection, or to join fuel lines together.
(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.
(9) 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.
BR/BEFUEL DELIVERY - GASOLINE 14 - 27
QUICK CONNECT FITTING (Continued)

FUEL INJECTION - GASOLINE
DIAGNOSIS AND TESTING
VISUAL INSPECTIONÐ5.9L ENGINES
A visual inspection for loose, disconnected or incor-
rectly routed wires and hoses should be made. This
should be done before attempting to diagnose or ser-
vice the fuel injection system. A visual check will
help spot these faults and save unnecessary test and
diagnostic time. A thorough visual inspection will
include the following checks:
(1) Verify that the three 32±way electrical connec-
tors are fully inserted into the connector of the pow-
ertrain control module (PCM) (Fig. 1).
(2) Inspect the battery cable connections. Be sure
that they are clean and tight.
(3) Inspect fuel pump relay and air conditioning
compressor clutch relay (if equipped). Inspect the
ASD relay connections. Inspect starter motor relay
connections. Inspect relays for signs of physical dam-
age and corrosion. The relays are located in the
Power Distribution Center (PDC) (Fig. 2). Refer to
label on PDC cover for relay location.
(4) Inspect ignition coil connections. Verify that
coil secondary cable is firmly connected to coil (Fig.
3).
(5) Verify that distributor cap is correctly attached
to distributor. Be sure that spark plug cables are
firmly connected to the distributor cap and the spark
plugs are in their correct firing order. Be sure that
coil cable is firmly connected to distributor cap and
coil. Be sure that camshaft position sensor wire con-nector (at the distributor) is firmly connected to har-
ness connector. Inspect spark plug condition. Refer to
8, Ignition. Connect vehicle to an oscilloscope and
inspect spark events for fouled or damaged spark
plugs or cables.
(6) Verify that generator output wire, generator
connector and ground wire are firmly connected to
the generator.
(7) Inspect the system body grounds for loose or
dirty connections. Refer to 8, Wiring for ground loca-
tions.
(8) Verify positive crankcase ventilation (PCV)
valve operation. Refer to 25, Emission Control Sys-
tem for additional information. Verify PCV valve
hose is firmly connected to PCV valve and manifold
(Fig. 4).
Fig. 1 Powertrain Control Module (PCM)
1 - PCM MOUNTING BOLTS (3)
2 - POWERTRAIN CONTROL MODULE (PCM)
3 - (3) 32±WAY CONNECTORS
Fig. 2 Power Distribution Center (PDC)
1 - POWER DISTRIBUTION CENTER (PDC)
Fig. 3 Ignition CoilÐ5.9L EnginesÐTypical
1 - ACCESSORY DRIVE BELT TENSIONER
2 - COIL CONNECTOR
3 - IGNITION COIL
4 - COIL MOUNTING BOLTS
BR/BEFUEL INJECTION - GASOLINE 14 - 29

(9) Inspect fuel tube quick-connect fitting-to-fuel
rail connections.
(10) Verify that hose connections to all ports of
vacuum fittings on intake manifold are tight and not
leaking.
(11) Inspect accelerator cable, transmission throt-
tle cable (if equipped) and cruise control cable con-
nections (if equipped). Check their connections to the
throttle arm of throttle body for any binding or
restrictions.
(12) If equipped with vacuum brake booster, verify
that vacuum booster hose is firmly connected to fit-
ting on intake manifold. Also check connection to
brake vacuum booster.
(13) Inspect the air cleaner inlet and air cleaner
element for dirt or restrictions.
(14) Inspect radiator grille area, radiator fins and
air conditioning condenser for restrictions.
(15) Verify that the intake manifold air tempera-
ture sensor wire connector is firmly connected to har-
ness connector (Fig. 5).
(16) Verify that MAP sensor electrical connector is
firmly connected to MAP sensor (Fig. 6). Also verify
that rubber L-shaped fitting from MAP sensor to the
throttle body is firmly connected (Fig. 7).
(17) Verify that fuel injector wire harness connec-
tors are firmly connected to injectors in the correct
order. Each harness connector is numerically tagged
with the injector number (INJ 1, INJ 2 etc.) of its
corresponding fuel injector and cylinder number.
(18) Verify harness connectors are firmly con-
nected to idle air control (IAC) motor, throttle posi-
tion sensor (TPS) and manifold absolute pressure
(MAP) sensor (Fig. 6).(19) Verify that wire harness connector is firmly
connected to the engine coolant temperature sensor
(Fig. 8).
(20) Raise and support the vehicle.
(21) Verify oxygen sensor wire connectors are
firmly connected to the sensors. Inspect sensors and
connectors for damage (Fig. 9), (Fig. 10) or (Fig. 11).
Fig. 4 PCV Valve
1 - P C V VA LV E
2 - PCV VALVE HOSE CONNECTIONS
Fig. 5 Air Temperature
1 - INTAKE MANIFOLD AIR TEMPERATURE SENSOR
2 - ELECTRICAL CONNECTOR
Fig. 6 Sensor and IAC Motor LocationÐTypical (V-8
Shown)
1 - MAP SENSOR
2 - IDLE AIR CONTROL MOTOR
3 - THROTTLE POSITION SENSOR
14 - 30 FUEL INJECTION - GASOLINEBR/BE
FUEL INJECTION - GASOLINE (Continued)

(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.
VISUAL INSPECTIONÐ8.0L ENGINE
A visual inspection for loose, disconnected or incor-
rectly routed wires and hoses should be made. This
should be done before attempting to diagnose or ser-
vice the fuel injection system. A visual check will
help spot these faults and save unnecessary test and
diagnostic time. A thorough visual inspection will
include the following checks:
(1) Verify that the three 32±way electrical connec-
tors are fully inserted into the connector of the pow-
ertrain control module (PCM) (Fig. 12).
(2) Inspect the battery cable connections. Be sure
that they are clean and tight.
(3) Inspect fuel pump relay and air conditioning
compressor clutch relay (if equipped). Inspect the
ASD relay connections. Inspect starter motor relay
connections. Inspect relays for signs of physical dam-
age and corrosion. The relays are located in the
Power Distribution Center (PDC) (Fig. 13). Refer to
label on PDC cover for relay location.
(4) Inspect ignition coil pack primary connections.
Verify that secondary cables are firmly connected to
coils (Fig. 14).
(5) Be sure that spark plug cables are firmly con-
nected and the spark plugs are in their correct firing
order. Be sure that camshaft position sensor wire
connector is firmly connected to harness connector.
Inspect spark plug condition. Refer to 8, Ignition.Connect vehicle to an oscilloscope and inspect spark
events for fouled or damaged spark plugs or cables.
(6) Verify that generator output wire, generator
connector and ground wire are firmly connected to
the generator.
(7) Inspect the system body grounds for loose or
dirty connections. Refer to 8, Wiring for ground loca-
tions.
(8) Verify crankcase ventilation (CCV) operation.
Refer to 25, Emission Control System for additional
information.
(9) Inspect fuel tube quick-connect fitting-to-fuel
rail connections.
(10) Verify that hose connections to all ports of
vacuum fittings on intake manifold are tight and not
leaking.
Fig. 11 Oxygen SensorsFig. 12 Powertrain Control Module (PCM)
1 - PCM MOUNTING BOLTS (3)
2 - POWERTRAIN CONTROL MODULE (PCM)
3 - (3) 32±WAY CONNECTORS
Fig. 13 Power Distribution Center (PDC)
1 - POWER DISTRIBUTION CENTER (PDC)
14 - 32 FUEL INJECTION - GASOLINEBR/BE
FUEL INJECTION - GASOLINE (Continued)