ignition DODGE RAM 2001 Service Repair Manual

DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTINGÐCYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing)
²Leaks between adjacent cylinders or into water
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn OFF the
engine.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or oil filler cap opening.
Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
Refer to CYLINDER COMBUSTION PRESSURE
LEAKAGE DIAGNOSIS CHART below
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
BR/BEENGINE 8.0L 9 - 179
ENGINE 8.0L (Continued)

(6) Remove the serpentine belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOV-
AL).
(7) Remove the A/C compressor with the lines
attached (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/A/C COMPRESSOR -
REMOVAL). Set aside.
(8) If equipped, remove the condenser (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING/
A/C CONDENSER - REMOVAL).
(9) Remove the washer fluid reservoir bottle (Refer
to 8 - ELECTRICAL/WIPERS/WASHERS -
REMOVAL AND INSTALLATION).
(10) Disconnect the top radiator hose.
(11) Remove the fan (Refer to 7 - COOLING/EN-
GINE/RADIATOR FAN - REMOVAL).
(12) Remove the fan shroud.
(13) Disconnect the lower radiator hose.
(14) Disconnect the transmission cooler lines.
(15) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(16) Remove the generator with the wire connec-
tions (Refer to 8 - ELECTRICAL/CHARGING/GEN-
ERATOR - REMOVAL).
(17) Remove the air cleaner.
(18) Disconnect the throttle linkage.
(19) Remove throttle body (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/THROTTLE BODY -
REMOVAL).
(20) Remove the upper intake manifold (Refer to 9
- ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(21) Remove the coil assemblies with the ignition
cables.
(22) Disconnect the heater hoses.
(23) Disconnect the power steering hoses, if
equipped.
(24) Perform the Fuel System Pressure release
procedure (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). Disconnect
the fuel line (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(25) On Manual Transmission vehicles, remove the
shift lever.
(26) Raise and support the vehicle on a hoist.
(27) Remove the drain plug and drain the engine
oil.
(28) Loosen front engine mount thru-bolt nuts.
(29) Remove the transmission cooler line brackets
from oil pan.
(30) Disconnect exhaust pipe at manifold.
(31) Disconnect the starter wires. Remove starter
motor (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - REMOVAL).
(32) Remove transmission.(33) Lower vehicle.
CAUTION: DO NOT lift the engine by the intake
manifold.
(34) Install an engine lifting fixture.
(35) Remove engine from vehicle and install
engine assembly on a repair stand.
INSTALLATION
(1) Remove engine from the repair stand and posi-
tion in the engine compartment. Position the thru-
bolt into the support cushion brackets.
(2) Install an engine support fixture.
(3) Raise and support the vehicle on a hoist.
(4) Install Transmission.
(5) Install the starter and connect the starter
wires (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - INSTALLATION).
(6) Install exhaust pipe to manifold.
(7) Install the transmission cooler line brackets
from oil pan.
(8) Tighten the Front mount thru-bolts and nuts to
102N´m (75 ft. lbs.).
(9) Install the drain plug and tighten to 34 N´m
(25 ft. lbs.) torque.
(10) Prime oil pump by squirting oil in the oil fil-
ter mounting hole and filling the J-trap of the front
timing cover. When oil is running out, install oil filter
that has been filled with oil.
(11) Lower the vehicle.
(12) Remove engine lifting fixture.
(13) On Manual Transmission vehicles, install the
shift lever.
(14) Connect the fuel lines (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE).
(15) Connect the heater hoses.
(16) Install the upper intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(17) Install the coil assemblies with the ignition
cables.
(18) Using a new gasket, install throttle body
(Refer to 14 - FUEL SYSTEM/FUEL INJECTION/
THROTTLE BODY - INSTALLATION).
(19) Connect the throttle linkage.
(20) Install the air cleaner box.
(21) Install the generator and wire connections
(Refer to 8 - ELECTRICAL/CHARGING/GENERA-
TOR - INSTALLATION).
(22) Install the upper crossmember.
(23) Install radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - INSTALLATION).
(24) Connect the lower radiator hose.
9 - 182 ENGINE 8.0LBR/BE
ENGINE 8.0L (Continued)

ARM / ADJUSTER ASSY - REMOVAL). Identify to
ensure installation in original locations.
(21) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(22) Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads. Be sure material does not fall into the lifters
and surrounding valley.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
Clean the exhaust manifold to cylinder head mat-
ing areas.
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. The out-of-flatness
specifications are 0.0007 mm/mm (0.0004 inch/inch),
0.127 mm/152 mm (0.005 inch/6 inches) any direction
or 0.254 mm (0.010 inch) overall across head. If
exceeded, either replace head or lightly machine the
head surface.
The cylinder head surface finish should be
1.78-4.57 microns (15-80 microinches).
Inspect push rods. Replace worn or bent rods.
Inspect rocker arms. Replace if worn or scored.
INSTALLATION
(1) Position the new cylinder head gaskets onto
the cylinder block.
(2) Position the cylinder heads onto head gaskets
and cylinder block.
(3) Tighten the cylinder head bolts in two steps
(Fig. 10):
²Step 1ÐTighten all cylinder head bolts, in
sequence, to 58 N´m (43 ft. lbs.) torque.
²Step 2ÐTighten all cylinder head bolts, in
sequence, to 143 N´m (105 ft. lbs.) torque.
²
CAUTION: When tightening the rocker arm bolts,
make sure the piston in that cylinder is NOT at
TDC. Contact between the valves and piston could
occur.
(4) Install push rods and rocker arm assemblies in
their original position (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARM / ADJUSTER ASSY -
INSTALLATION).
(5) Install lower intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).(6) Install the upper intake manifold onto the
lower intake manifold (Refer to 9 - ENGINE/MANI-
FOLDS/INTAKE MANIFOLD - INSTALLATION).
(7) Install the exhaust manifolds and new gaskets
(Refer to 9 - ENGINE/MANIFOLDS/EXHAUST
MANIFOLD - INSTALLATION).
(8) Install exhaust pipe to the exhaust manifold.
Tighten the bolts to 34 n´m (25 ft. lbs.) torque.
(9) Using a new gasket, position the EGR tube to
the intake manifold and the exhaust manifold.
Tighten the EGR tube nut to 34 N´m (25 ft. lbs.)
torque. Tighten the bolts to 20 N´m (174 in. lbs.)
torque.
(10) Install the heat shields and the washers.
Make sure that heat shields tabs hook over the
exhaust gasket.Tighten the nuts to 15 N´m (132 in.
lbs.) torque.
(11) Adjust and Install the spark plugs (Refer to 8
- ELECTRICAL/IGNITION CONTROL/SPARK
PLUG - INSTALLATION).
(12) Install coil packs and bracket. Tighten the
bracket bolts to 21 N´m (190 in. lbs.) torque. Connect
the coil wires.
(13) Connect heat indicator sending unit wire.
(14) Connect the heater hoses and bypass hose.
(15) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(16) Install the fuel line (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE).
(17) Install the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - INSTALLATION)
and drive belt (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - INSTALLATION).
(18) Install the intake manifold-to-generator
bracket support rod. Tighten the bolts to 41 N´m (30
ft. lbs.) torque.
(19) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.For the
left side the number tab is at the front of
engine with the number up. For the right side
the number tab is at the rear of engine with the
number up.
Fig. 10 Cylinder Head Bolt Tightening Sequence
BR/BEENGINE 8.0L 9 - 193
CYLINDER HEAD (Continued)

(3) Inspect the valve seat with Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seat LIGHTLY with Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to the top edge of valve face, lower valve seat
with a 15É stone. If the blue is transferred to bottom
edge of valve face raise valve seat with a 60É stone.
(4) When seat is properly positioned the width of
valve seats should be 1.016-1.524 mm (0.040-0.060
inch).
VALVE SPRING INSPECTION
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested. As an example the compression length of
the spring to be tested is 1-5/16 inch. Turn table of
Universal Valve Spring Tester Tool until surface is in
line with the 1-5/16 inch mark on the threaded stud.
Be sure the zero mark is to the front (Fig. 19). Place
spring over stud on the table and lift compressing
lever to set tone device. Pull on torque wrench until
ping is heard. Take reading on torque wrench at this
instant. Multiply this reading by 2. This will give the
spring load at test length. Fractional measurements
are indicated on the table for finer adjustments.
Refer to specifications to obtain specified height and
allowable tensions. Discard the springs that do not
meet specifications.
REMOVALÐVALVE STEM SEALS
NOTE: This procedure is done with the cylinder
head installed.
(1) Disconnect the negative cable from the battery.
(2) Set engine basic timing to Top Dead Center
(TDC) and remove air cleaner.
(3) Remove cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL) and spark plugs (Refer to 8
- ELECTRICAL/IGNITION CONTROL/SPARK
PLUG - REMOVAL).
(4) Using suitable socket and flex handle at crank-
shaft retaining bolt, turn engine so that the piston of
the cylinder to be worked on, is at TDC on the com-
pression stroke.
(5) Remove rocker arms (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARM / ADJUSTER
ASSY - REMOVAL).
(6) With air hose attached to an adapter installed
in the spark plug hole, apply 620-689 kPa (90-100
psi) air pressure.
(7) Using Valve Spring Compressor Tool
MD-998772A with adapter 6716A (Fig. 20), compress
valve spring and remove retainer valve locks and
valve spring.
(8) Remove the valve stem seal.
REMOVALÐVALVES AND VALVE SPRINGS
(1) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Special studs must be used to adapt the Valve
Spring Compressor Tool to the V-10 cylinder head
(Fig. 21). Install the metric end into the Special Tool
MD998772A and the 5/16 end into the cylinder head.
Fig. 18 Intake and Exhaust Valves
1 - MARGIN
2 - VALVE SPRING RETAINER LOCK GROOVE
3 - STEM
4-FACE
Fig. 19 Testing Valve Spring for Compressed
1 - TORQUE WRENCH
2 - VALVE SPRING TESTER
BR/BEENGINE 8.0L 9 - 197
INTAKE/EXHAUST VALVES & SEATS (Continued)

(6) Remove the air cleaner cover and filter.
Remove the air cleaner housing (Fig. 70). Discard the
gasket.
(7) Perform the Fuel System Pressure release pro-
cedure (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY - STANDARD PROCEDURE). Disconnect the
fuel lines (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(8) Disconnect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(9) Remove the coil assemblies with the ignition
wires.
(10) Disconnect the vacuum lines.
(11) Disconnect the heater hoses and bypass hose.
(12) Remove the closed crankcase ventilation and
evaporation control systems.
(13) Remove the throttle body bolts and lift the
throttle body off the upper intake manifold (Fig. 71).
Discard the gasket.
(14) Remove upper intake manifold bolts.
(15) Lift the upper intake manifold out of the
engine compartment (Fig. 71). Discard the gasket.
(16) Remove the lower intake manifold bolts and
remove the manifold (Fig. 72).
(17) Discard the lower intake manifold gaskets
(Fig. 73).
CLEANING
Clean manifold in solvent and blow dry with com-
pressed air.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
The plenum pan rail must be clean and dry (free of
all foreign material).
INSPECTION
Inspect manifold for cracks.
Inspect mating surfaces of manifold for flatness
with a straightedge.
INSTALLATION
(1) Install the intake manifold side gaskets. Be
sure that the locator dowels are positioned in the
head (Fig. 74).
(2) Insert MopartGEN II Silicone Rubber Adhe-
sive Sealant, or equivalent, into the four corner joints
an excessive amount of sealant is not required to
ensure a leak proof seal. However, an excessive
amount of sealant may reduce the effectiveness of
the flange gasket. The sealant should be approxi-
mately 5 mm (0.2 in.) in diameter. (Fig. 73).
Fig. 70 Air Intake Housing
1 - AIR INTAKE HOUSING
Fig. 71 Upper Intake Manifold and Throttle Body
1 - UPPER INTAKE MANIFOLD
2 - THROTTLE BODY (MPI)
3 - LOWER INTAKE MANIFOLD
Fig. 72 Lower Intake Manifold
BR/BEENGINE 8.0L 9 - 223
INTAKE MANIFOLD (Continued)

(3) Position the cross-over gaskets and press firmly
onto the block (Fig. 73).BE SURE THE BLOCK IS
OIL FREE..
(4) The lower intake manifold MUST be installed
within 3 minutes of sealant application. Carefully
lower intake manifold into position on the cylinder
block and heads. After intake manifold is in place,
inspect to make sure seals and gaskets are in place.
Finger start all the lower intake bolts.
(5) Tighten the lower intake manifold bolts in
sequence to 54 N´m (40 ft. lbs.) torque (Fig. 72).Recheck all bolts are tightened to 54 N´m (40 ft. lbs.)
torque.
(6) Using a new gasket, position the upper intake
manifold onto the lower intake manifold.
(7) Finger start all bolts, alternate one side to the
other.
(8) Tighten upper intake manifold bolts in
sequence to 22 N´m (16 ft. lbs.) torque (Fig. 71).
(9) Using a new gasket, install the throttle body
onto the upper intake manifold. Tighten the bolts to
23 N´m (200 in. lbs.) torque.
(10) Install closed crankcase ventilation and evap-
oration control systems.
(11) Connect the heater hoses and bypass hose.
(12) Connect the vacuum lines.
(13) Install the coil assemblies and the ignition
wires.
(14) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(15) Install the fuel lines (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE).
(16) Using a new gasket, install the air cleaner
housing. Tighten the nuts to 11 N´m (96 in. lbs.)
torque. Install the air cleaner filter and cover.
(17) Install the A/C compressor (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
COMPRESSOR - INSTALLATION). Position the com-
pressor brace and install the bolts. Tighten the brace
bolts to 41 N´m (30 ft. lbs.) torque.
(18) Install the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - INSTALLATION).
Position the generator brace and install the bolts.
Tighten the brace bolts to 41 N´m (30 ft. lbs.) torque.
(19) Install the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(20) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(21) Connect the negative cable to the battery.
(22) Start engine check for leaks.
EXHAUST MANIFOLD
DESCRIPTION
Engine exhaust manifolds (Fig. 75) are made of
high molybdenum ductile cast iron. A special ribbed
design helps control permanent dimensional changes
during heat cycles.
OPERATION
The exhaust manifolds collect the engine exhaust
exiting the combustion chambers, then channels the
Fig. 73 Lower Intake Manifold Gaskets
1 - INTAKE MANIFOLD GASKET
2 - SEALANT
3 - CROSS-OVER GASKETS
4 - SEALANT
5 - LOCATOR DOWELS
Fig. 74 Intake Manifold Flange
1 - LOCATOR DOWELS
2 - INTAKE MANIFOLD GASKETS
3 - LOCATOR DOWELS
9 - 224 ENGINE 8.0LBR/BE
INTAKE MANIFOLD (Continued)

(4) Connect the 0-414 kPa (0-60 psi) fuel pressure
test gauge (from Gauge Set 5069) to the test port on
the appropriate Adaptor Tool.The DRBtIII Scan
Tool along with the PEP module, the 500 psi
pressure transducer, and the transducer-to-test
port adapter may also be used in place of the
fuel pressure gauge.
The fittings on both tools must be in good
condition and free from any small leaks before
performing the proceeding test.
(5) Start engine and bring to normal operating
temperature.
(6) Observe test gauge. Normal operating pressure
should be 339 kPa +/±34 kPa (49.2 psi +/±5 psi).
(7) Shut engine off.
(8) Pressure should not fall below30 psi for five
minutes.
(9) If pressure falls below 30 psi, it must be deter-
mined if a fuel injector, the check valve within the
fuel pump module, or a fuel tube/line is leaking.
(10) Again, start engine and bring to normal oper-
ating temperature.
(11) Shut engine off.
(12)Testing for fuel injector or fuel rail leak-
age:Clamp off the rubber hose portion of Adaptor
Tool between the fuel rail and the test port ªTº on
Adapter Tool. If pressure now holds at or above 30
psi, a fuel injector or the fuel rail is leaking.
(13)Testing for fuel pump check valve, filter/
regulator check valve or fuel tube/line leakage:
Clamp off the rubber hose portion of Adaptor Tool
between the vehicle fuel line and test port ªTº on
Adapter Tool. If pressure now holds at or above 30
psi, a leak may be found at a fuel tube/line. If no
leaks are found at fuel tubes or lines, one of the
check valves in either the electric fuel pump or filter/
regulator may be leaking.
Note: A quick loss of pressure usually indicates a
defective check valve in the filter/regulator. A slow
loss of pressure usually indicates a defective check
valve in the electric fuel pump.
The electric fuel pump is not serviced separately.
Replace the fuel pump module assembly. The filter/
regulator may be replaced separately on certain
applications. Refer to Fuel Filter/Fuel Pressure Reg-
ulator Removal/Installation for additional informa-
tion.STANDARD PROCEDURE - FUEL SYSTEM
PRESSURE RELEASE
Use following procedure if the fuel injector
rail is, or is not equipped with a fuel pressure
test port.
(1) Remove fuel fill cap.
(2) Remove fuel pump relay from Power Distribu-
tion Center (PDC). For location of relay, refer to label
on underside of PDC cover.
(3) Start and run engine until it stalls.
(4) Attempt restarting engine until it will no
longer run.
(5) Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to
relieve high pressure fuel from within fuel rail. Do
not attempt to use following steps to relieve this
pressure as excessive fuel will be forced into a cyl-
inder chamber.
(6) Unplug connector from any fuel injector.
(7) Attach one end of a jumper wire with alligator
clips (18 gauge or smaller) to either injector terminal.
(8) Connect other end of jumper wire to positive
side of battery.
(9) Connect one end of a second jumper wire to
remaining injector terminal.
CAUTION: Powering an injector for more than a few
seconds will permanently damage the injector.
(10) Momentarily touch other end of jumper wire
to negative terminal of battery for no more than a
few seconds.
(11) Place a rag or towel below fuel line quick-con-
nect fitting at fuel rail.
(12) Disconnect quick-connect fitting at fuel rail.
Refer to Quick-Connect Fittings.
(13) Return fuel pump relay to PDC.
(14) One or more Diagnostic Trouble Codes (DTC's)
may have been stored in PCM memory due to fuel
pump relay removal. The DRBtscan tool must be
used to erase a DTC.
BR/BEFUEL DELIVERY - GASOLINE 14 - 3
FUEL DELIVERY - GASOLINE (Continued)

(7) 3.9L (V-6) engine only: Disconnect electrical
connector at intake manifold air temperature sensor.
Do not remove sensor.
(8) Disconnect fuel tube (line) at side of fuel rail.
Refer to Quick-Connect Fittings for procedures,
(9) Remove the remaining fuel rail mounting bolts.
(10) Gently rock and pull theleftfuel rail until
the fuel injectors just start to clear the intake mani-
fold. Gently rock and pull therightfuel rail until
the fuel injectors just start to clear the intake mani-
fold. Repeat this procedure (left/right) until all fuel
injectors have cleared the intake manifold.
(11) Remove fuel rail (with injectors attached)
from engine.
(12) Remove the clip(s) retaining the injector(s) to
fuel rail (Fig. 30) or (Fig. 31).
REMOVAL - 8.0L
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE EVEN WITH THE ENGINE OFF.
BEFORE SERVICING FUEL RAIL, FUEL SYSTEM
PRESSURE MUST BE RELEASED.
(1) Remove negative battery cable at battery.
(2) Remove air cleaner housing and tube.
(3) Perform fuel pressure release procedure. Refer
to Fuel Delivery System section of this group.
(4) Disconnect throttle body linkage and remove
throttle body from intake manifold. Refer to Throttle
Body removal in this group.
(5) Remove ignition coil pack and bracket assem-
bly (Fig. 32) at intake manifold and right engine
valve cover (four bolts).
(6) Remove upper half of intake manifold. Refer to
Engines for procedures.
Fig. 30 Fuel Injector MountingÐTypical
1 - CLIP
2 - INJECTOR
3 - FUEL RAIL
Fig. 31 Injector Retaining ClipsÐTypical Injector
1 - PLIERS
2 - INJECTOR CLIP
3 - FUEL INJECTOR
4 - FUEL RAIL
Fig. 32 Ignition Coil Pack and Mounting BracketÐ
8.0L V-10 Engine
1 - COIL PACKS AND BRACKET
2 - MOUNTING BOLTS (4)
BR/BEFUEL DELIVERY - GASOLINE 14 - 17
FUEL RAIL (Continued)

INSTALLATION - 8.0L
(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.
NOTE: The fuel injector electrical connectors on all
10 injectors should be facing to the right (passen-
ger) side of the vehicle (Fig. 34).
(3) Position the fuel rail/fuel injector assembly to
the injector openings on the intake manifold.
(4) Guide each injector into the intake manifold.
Be careful not to tear the injector o-ring.
(5) Push therightfuel rail down until fuel injec-
tors have bottomed on injector shoulder. Push the
leftfuel rail down until fuel injectors have bottomed
on injector shoulder.
(6) Install the six fuel rail mounting bolts into the
lower half of intake manifold. Tighten bolts to 15
N´m (136 in. lbs.) torque.
(7) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 33). 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. The injector wir-
ing harness is numerically tagged.
(8) Install upper half of intake manifold. Refer to
Engines for procedures.
(9) Connect main fuel line at fuel rail. Refer to
Quick-Connect Fittings for procedures.
(10) Install ignition coil pack and bracket assem-
bly at intake manifold and right engine valve cover
(four bolts).
(11) Install throttle body to intake manifold. Refer
to Throttle Body removal in this group.
(12) Install throttle body linkage to throttle body.
(13) Install air cleaner tube and housing.
(14) Install negative battery cable at battery.
(15) Start engine and check for leaks.
FUEL TANK
DESCRIPTION
The fuel tank is constructed of a plastic material.
Its main functions are for fuel storage and for place-
ment of the fuel pump module.
OPERATION
All models pass a full 360 degree rollover test
without fuel leakage. To accomplish this, fuel and
vapor flow controls are required for all fuel tank con-
nections.A rollover valve(s) is mounted into the top of the
fuel tank (or pump module). Refer to Emission Con-
trol System for rollover valve information.
An evaporation control system is connected to the
rollover valve(s) to reduce emissions of fuel vapors
into the atmosphere. When fuel evaporates from the
fuel tank, vapors pass through vent hoses or tubes to
a charcoal canister where they are temporarily held.
When the engine is running, the vapors are drawn
into the intake manifold. Certain models are also
equipped with a self-diagnosing system using a Leak
Detection Pump (LDP). Refer to Emission Control
System for additional information.
REMOVAL
WARNING: GASOLINE POWERED ENGINES: THE
FUEL SYSTEM IS UNDER A CONSTANT PRESSURE
EVEN WITH THE ENGINE OFF. BEFORE SERVICING
THE FUEL TANK, FUEL SYSTEM PRESSURE MUST
BE RELEASED. REFER TO THE FUEL SYSTEM
PRESSURE RELEASE PROCEDURE BEFORE SER-
VICING THE FUEL TANK.
Two different procedures may be used to drain fuel
tank (lowering tank or using DRB scan tool). When
equipped with a diesel engine, the DRB scan tool
cannot be used (no electric fuel pump).
The quickest draining procedure involves lowering
the fuel tank.
Gasoline Powered Engines:As an alternative
procedure, the electric fuel pump may be activated
allowing tank to be drained at fuel rail connection.
Refer to DRB scan tool for fuel pump activation pro-
cedures. Before disconnecting fuel line at fuel rail,
release fuel pressure. Refer to the Fuel System Pres-
sure Release Procedure in this group for procedures.
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.
BR/BEFUEL DELIVERY - GASOLINE 14 - 19
FUEL RAIL (Continued)

FUEL INJECTION - GASOLINE
TABLE OF CONTENTS
page page
FUEL INJECTION - GASOLINE
DIAGNOSIS AND TESTING.................28
VISUAL INSPECTION - 3.9L/5.2L/5.9L
ENGINES.............................28
VISUAL INSPECTION - 8.0L ENGINE........32
SPECIFICATIONS........................35
SPECIAL TOOLS.........................36
ACCELERATOR PEDAL
REMOVAL..............................37
INSTALLATION...........................37
CRANKSHAFT POSITION SENSOR
DESCRIPTION...........................38
OPERATION.............................38
REMOVAL..............................39
INSTALLATION...........................40
FUEL PUMP RELAY
DESCRIPTION...........................41
OPERATION.............................41
REMOVAL..............................41
INSTALLATION...........................41
IDLE AIR CONTROL MOTOR
DESCRIPTION...........................41
OPERATION.............................41
REMOVAL..............................42
INSTALLATION...........................42
INTAKE AIR TEMPERATURE SENSOR
DESCRIPTION...........................43
OPERATION.............................43
REMOVAL..............................43
INSTALLATION...........................43
MANIFOLD ABSOLUTE PRESSURE SENSOR
DESCRIPTION...........................44OPERATION.............................44
REMOVAL..............................45
INSTALLATION...........................45
O2 SENSOR
DESCRIPTION...........................46
OPERATION.............................46
REMOVAL..............................47
INSTALLATION...........................48
PTO SWITCH
DESCRIPTION...........................48
OPERATION.............................48
THROTTLE BODY
DESCRIPTION...........................48
OPERATION.............................48
REMOVAL..............................48
INSTALLATION...........................49
THROTTLE CONTROL CABLE
REMOVAL..............................50
INSTALLATION...........................50
THROTTLE POSITION SENSOR
DESCRIPTION...........................51
OPERATION.............................51
REMOVAL..............................51
INSTALLATION...........................52
FUEL INJECTOR
DESCRIPTION...........................53
OPERATION.............................53
DIAGNOSIS AND TESTING.................53
FUEL INJECTOR TEST...................53
REMOVAL..............................53
INSTALLATION...........................53
FUEL INJECTION - GASOLINE
VISUAL INSPECTIONÐ3.9L/5.2L/5.9L
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).
14 - 28 FUEL INJECTION - GASOLINEBR/BE