torque DODGE RAM 2002 Service Repair Manual

Starter Motor and Solenoid
Solenoid Closing Maximum
Voltage Required7.5 Volts 7.5 Volts 8.0 Volts
* Cranking Amperage Draw
Test125 - 250 Amperes 125 - 250 Amperes 450 - 700 Amperes
* Test at operating temperature. Cold engine, tight (new) engine, or heavy oil will increase starter amperage draw.
SPECIFICATIONS - TORQUE - STARTING
SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Battery Cable Eyelet Nut
at Solenoid (large nut -
gas engines)25 19 221
Battery Cable Eyelet Nut
at Solenoid (large nut -
diesel engine)14 - 120
Starter Solenoid Nut
(small nut - diesel engine)6-55
Starter Mounting Bolts -
Gas Engines68 50 -
Starter Mounting Nut -
Gas Engines68 50 -
Starter Mounting Bolts -
Diesel43 32 -
STARTER MOTOR
DESCRIPTION
The starter motors used for the 5.9L diesel engine
and the 8.0L gasoline engine available in this model
are not interchangeable with each other, or with the
starter motors used for the other available engines.
The starter motor for the 5.9L diesel engine is
mounted with three screws to the flywheel housing
on the left side of the engine. The starter motor for
the 8.0L gasoline engine is mounted with two screws
to the flange on the left rear corner of the engine
block, while the starter motor for the 5.9L Gas
engine is mounted with one screw, a stud and a nut
to the manual transmission clutch housing or auto-
matic transmission torque converter housing and is
located on the left side of the engine.
Each of these starter motors incorporates several
of the same features to create a reliable, efficient,
compact, lightweight and powerful unit. The electric
motors of all of these starters have four brushes con-
tacting the motor commutator, and feature four elec-
tromagnetic field coils wound around four pole shoes.
The 5.9L and 8.0L gasoline engine starter motors are
rated at 1.4 kilowatts (about 1.9 horsepower) outputat 12 volts, while the 5.9L diesel engine starter
motor is rated at 2.7 kilowatts (about 3.6 horse-
power) output at 12 volts.
All of these starter motors are serviced only as a
unit with their starter solenoids, and cannot be
repaired. If either component is faulty or damaged,
the entire starter motor and starter solenoid unit
must be replaced.
OPERATION
These starter motors are equipped with a gear
reduction (intermediate transmission) system. The
gear reduction system consists of a gear that is inte-
gral to the output end of the electric motor armature
shaft that is in continual engagement with a larger
gear that is splined to the input end of the starter
pinion gear shaft. This feature makes it possible to
reduce the dimensions of the starter. At the same
time, it allows higher armature rotational speed and
delivers increased torque through the starter pinion
gear to the starter ring gear.
The starter motors for all engines are activated by
an integral heavy duty starter solenoid switch
mounted to the overrunning clutch housing. This
electromechanical switch connects and disconnects
BR/BESTARTING 8F - 37
STARTING (Continued)

the feed of battery voltage to the starter motor, also
engaging and disengaging the starter pinion gear
with the starter ring gear.
All starter motors use an overrunning clutch and
starter pinion gear unit to engage and drive a starter
ring gear that is integral to the flywheel (manual
transmission), torque converter or torque converter
drive plate (automatic transmission) mounted on the
rear crankshaft flange.
DIAGNOSIS AND TESTING - STARTER MOTOR
Correct starter motor operation can be confirmed
by performing the following free running bench test.
This test can only be performed with starter motor
removed from vehicle. Refer to Starter Specifications
for starter motor specifications.
(1) Remove starter motor from vehicle. Refer to
Starter MotorRemoval and Installation.
(2) Mount starter motor securely in a soft-jawed
bench vise. The vise jaws should be clamped on
mounting flange of starter motor. Never clamp on
starter motor by field frame.
(3) Connect suitable volt-ampere tester and 12-volt
battery to starter motor in series, and set ammeter to
100 ampere scale (250 ampere scale for diesel engine
starters). See instructions provided by manufacturer
of volt-ampere tester being used.
(4) Install jumper wire from solenoid terminal to
solenoid battery terminal. The starter motor should
operate. If starter motor fails to operate, replace
faulty starter motor assembly.
(5) Adjust carbon pile load of tester to obtain free
running test voltage. Refer to Specifications for the
starter motor free running test voltage specifications.
(6) Note reading on ammeter and compare this
reading to free running test maximum amperage
draw. Refer to Specifications for starter motor free
running test maximum amperage draw specifica-
tions.
(7) If ammeter reading exceeds maximum amper-
age draw specification, replace faulty starter motor
assembly.
STARTER MOTOR SOLENOID
This test can only be performed with starter motor
removed from vehicle.
(1) Remove starter motor. Refer toStarter Motor
Removal and Installation.
(2) Disconnect wire from solenoid field coil termi-
nal.
(3) Check for continuity between solenoid terminal
and solenoid field coil terminal with continuity tester
(Fig. 7). There should be continuity. If OK, go to Step
4. If not OK, replace faulty starter motor assembly.(4) Check for continuity between solenoid terminal
and solenoid case (Fig. 8). There should be continuity.
If not OK, replace faulty starter motor assembly.
REMOVAL
5.9L GASOLINE ENGINE
(1) Disconnect and isolate negative battery cable.
(2) Raise and support vehicle.
(3) Remove nut and lock washer securing starter
motor to mounting stud (Fig. 9).
(4) While supporting starter motor, remove upper
mounting bolt from starter motor.
(5) If equipped with automatic transmission, slide
cooler tube bracket forward on tubes far enough for
starter motor mounting flange to be removed from
lower mounting stud.
(6) Move starter motor towards front of vehicle far
enough for nose of starter pinion housing to clear
housing. Always support starter motor during this
process, do not let starter motor hang from wire har-
ness.
(7) Tilt nose downwards and lower starter motor
far enough to access and remove nut that secures
battery positive cable wire harness connector eyelet
Fig. 7 Continuity Test Between Solenoid Terminal
and Field Coil Terminal - Typical
1 - OHMMETER
2 - SOLENOID TERMINAL
3 - FIELD COIL TERMINAL
Fig. 8 Continuity Test Between Solenoid Terminal
and Solenoid Case - Typical
1 - SOLENOID TERMINAL
2 - OHMMETER
3 - SOLENOID
8F - 38 STARTINGBR/BE
STARTER MOTOR (Continued)

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION - 8.0L V-10.................2
OPERATION
OPERATION - 8.0L V-10.................2
OPERATION - V-8......................2
SPECIFICATIONS
SPECIFICATIONS - TORQUE - IGNITION....2
SPARK PLUG CABLE ORDERÐ8.0L V-10
ENGINE..............................3
ENGINE FIRING ORDERÐ5.9L V-8
ENGINES............................3
SPARK PLUG CABLE RESISTANCE........3
SPARK PLUGS........................3
IGNITION COIL RESISTANCEÐ5.9L
ENGINES............................3
IGNITION COIL RESISTANCEÐ8.0L V-10
ENGINE..............................4
IGNITION TIMING......................4
AUTOMATIC SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............4
OPERATION
OPERATION - PCM OUTPUT.............4
OPERATION - ASD SENSE - PCM INPUT....4
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................4
REMOVAL.............................5
INSTALLATION..........................5
CAMSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - DIESEL.................6
DESCRIPTION - 5.9L....................6
DESCRIPTION - 8.0L....................6
OPERATION
OPERATION - DIESEL...................6
OPERATION - 5.9L.....................7
OPERATION - 8.0L.....................7
REMOVAL
REMOVAL - DIESEL....................7
REMOVAL - 5.9L.......................7
REMOVAL - 8.0L.......................8
INSTALLATION
INSTALLATION - DIESEL.................9INSTALLATION - 5.9L..................10
INSTALLATION - 8.0L..................10
DISTRIBUTOR
DESCRIPTION.........................11
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................13
DISTRIBUTOR CAP
DIAGNOSIS AND TESTING - DISTRIBUTOR
CAP ................................14
DISTRIBUTOR ROTOR
DIAGNOSIS AND TESTING - DISTRIBUTOR
ROTOR .............................14
IGNITION COIL
DESCRIPTION
DESCRIPTION - 5.9L...................15
DESCRIPTION - 8.0L...................15
OPERATION
OPERATION - 5.9L....................15
OPERATION - 8.0L....................15
REMOVAL
REMOVAL - 5.9L......................15
REMOVAL - 8.0L......................16
INSTALLATION
INSTALLATION - 5.9L..................16
INSTALLATION - 8.0L..................16
SPARK PLUG
DESCRIPTION.........................16
OPERATION...........................16
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................17
REMOVAL.............................19
CLEANING............................20
INSTALLATION.........................20
SPARK PLUG CABLE
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING - SPARK PLUG
CABLES............................20
REMOVAL.............................21
INSTALLATION.........................21
BR/BEIGNITION CONTROL 8I - 1

IGNITION CONTROL
DESCRIPTION - 8.0L V-10
The ignition system used on the 8.0L V±10 engine
does not use a conventional mechanical distributor.
The system will be referred to as a distributor-less
ignition system.
OPERATION
OPERATION - 8.0L V-10
The ignition coils are individually fired, but each
coil is a dual output. Refer to Ignition Coil for addi-
tional information.
The ignition system is controlled by the Powertrain
Control Module (PCM) on all engines.
The ignition system consists of:
²Spark Plugs
²Ignition Coil packs containing individual coils
²Secondary Ignition Cables²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position and MAP Sen-
sors
OPERATION - V-8
The ignition system is controlled by the Powertrain
Control Module (PCM) on all engines.
The ignition system consists of:
²Spark Plugs
²Ignition Coil
²Secondary Ignition Cables
²Distributor (contains rotor and camshaft position
sensor)
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position and MAP Sen-
sors
SPECIFICATIONS
SPECIFICATIONS - TORQUE - IGNITION
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Camshaft Position
SensorÐ8.0L Engine6
-50
Crankshaft Position
SensorÐAll Engines8-70
Distributor Hold Down Bolt 23 17 -
Ignition Coil MountingÐ
5.9L EnginesÐif tapped
bolts are used5-50
Ignition Coil MountingÐ
5.9L EnginesÐif nuts/bolts
are used11 - 100
Ignition Coil MountingÐ
8.0L Engine10 - 90
Spark Plugs (all engines) 41 - 30
8I - 2 IGNITION CONTROLBR/BE

(4) Install mounting bolt and tighten to 20 Nm (15
ft. lbs.) torque.
(5) Install electrical connector to CMP.
(6) Connect both negative cables to both batteries.
INSTALLATION - 5.9L
The camshaft position sensor is located in the dis-
tributor (Fig. 11).
(1) Install camshaft position sensor to distributor.
Align sensor into notch on distributor housing.
(2) Connect wiring harness.
(3) Install rotor.
(4) Install distributor cap. Tighten mounting
screws.
(5) Install air cleaner assembly.
INSTALLATION - 8.0L
If Replacing Old Sensor With Original
The camshaft position sensor is located on the tim-
ing chain case/cover on the left-front side of the
engine (Fig. 12).
When installing a used camshaft position sensor,
the sensor depth must be adjusted to prevent contact
with the camshaft gear (sprocket).
(1) Observe the face of the sensor. If any of the
original rib material remains (Fig. 13), it must be cut
down flush to the face of the sensor with a razor
knife. Remove only enough of the rib material until
the face of the sensor is flat. Do not remove more
material than necessary as damage to sensor may
result. Due to a high magnetic field and possible elec-
trical damage to the sensor, never use an electric
grinder to remove material from sensor.
(2) From the parts department, obtain a peel-and-
stick paper spacer (Fig. 13). These special paper
spacers are of a certain thickness and are to be used
as a tool to set sensor depth.
(3) Clean the face of sensor and apply paper
spacer (Fig. 13).
(4) Apply a small amount of engine oil to the sen-
sor o-ring (Fig. 14).
A low and high area are machined into the cam-
shaft drive gear (Fig. 15). The sensor is positioned in
the timing gear cover so that a small air gap (Fig.
15) exists between the face of sensor and the high
machined area of cam gear.
Before the sensor is installed, the cam gear may
have to be rotated. This is to allow the high
machined area on the gear to be directly in front of
the sensor mounting hole opening on the timing gear
cover.
Do not install sensor with gear positioned at
low area (Fig. 16) or (Fig. 15). When the engine
is started, the sensor will be broken.(5) Using a 1/2 in. wide metal ruler, measure the
distance from the cam gear to the face of the sensor
mounting hole opening on the timing gear cover (Fig.
16).
(6) If the dimension is approximately 1.818 inches,
it is OK to install sensor. Proceed to step Step 9.
(7) If the dimension is approximately 2.018 inches,
the cam gear will have to be rotated.
(8) Attach a socket to the vibration damper mount-
ing bolt and rotate engine until the 1.818 inch
dimension is attained.
(9) Install the sensor into the timing case/cover
with a slight rocking action until the paper spacer
contacts the camshaft gear. Do not install the sensor
mounting bolt. Do not twist the sensor into position
as damage to the o-ring or tearing of the paper
spacer may result.
(10) Scratch a scribe line into the timing chain
case/cover to indicate depth of sensor (Fig. 14).
(11) Remove the sensor from timing chain case/
cover.
(12) Remove the paper spacer from the sensor.
This step must be followed to prevent the paper
spacer from getting into the engine lubrication sys-
tem.
(13) Again, apply a small amount of engine oil to
sensor o-ring.
Fig. 15 Sensor OperationÐ8.0L V-10 Engine
1 - CAM DRIVE GEAR
2 - LOW MACHINED AREA
3 - HIGH MACHINED AREA
4 - CAMSHAFT POSITION SENSOR
5 - AIR GAP
8I - 10 IGNITION CONTROLBR/BE
CAMSHAFT POSITION SENSOR (Continued)

(14) Again, install the sensor into the timing case/
cover with a slight rocking action until the sensor is
aligned to scribe line.
(15) Install sensor mounting bolt and tighten to 6
N´m (50 in. lbs.) torque.
(16) Connect engine wiring harness to sensor.
Replacing With a New Sensor
(1) Apply a small amount of engine oil to the sen-
sor o-ring (Fig. 14).
A low and high area are machined into the cam-
shaft drive gear (Fig. 15). The sensor is positioned in
the timing gear cover so that a small air gap (Fig.
15) exists between the face of sensor and the high
machined area of cam gear.
Before the sensor is installed, the cam gear may
have to be rotated. This is to allow the high
machined area on the gear to be directly in front of
the sensor mounting hole opening on the timing gear
cover.
Do not install sensor with gear positioned at
low area (Fig. 16) or (Fig. 15). When the engine
is started, the sensor will be broken.(2) Using a 1/2 in. wide metal ruler, measure the
distance from the cam gear to the face of the sensor
mounting hole opening on the timing gear cover (Fig.
16).
(3) If the dimension is approximately 1.818 inches,
it is OK to install sensor. Proceed to step Step 9.
(4) If the dimension is approximately 2.018 inches,
the cam gear will have to be rotated.
(5) Attach a socket to the vibration damper mount-
ing bolt and rotate engine until the 1.818 inch
dimension is attained.
(6) Install the sensor into the timing case/cover
with a slight rocking action. Do not twist the sensor
into position as damage to the o-ring may result.
Push the sensor all the way into the cover until the
rib material on the sensor (Fig. 13) contacts the cam-
shaft gear.
(7) Install the mounting bolt and tighten to 6 N´m
(50 in. lbs.) torque.
(8) Connect sensor wiring harness to engine har-
ness.
When the engine is started, the rib material will be
sheared off the face of sensor. This will automatically
set sensor air gap.
DISTRIBUTOR
DESCRIPTION
All 5.9L engines are equipped with a camshaft
driven mechanical distributor (Fig. 17) containing a
shaft driven distributor rotor. All distributors are
equipped with an internal camshaft position (fuel
sync) sensor (Fig. 17).
Fig. 16 Sensor Depth Dimensions
1 - 2.018©© DO NOT INSTALL SENSOR
2 - SENSOR MOUNTING HOLE OPENING
3 - SENSOR CENTER LINE
4 - TIMING CHAIN COVER
5 - 1.818©© OK TO INSTALL SENSOR
6 - CAM DRIVE GEAR
7 - HIGH MACHINED AREA
8 - LOW MACHINED AREA
Fig. 17 Distributor and Camshaft Position Sensor
1 - SYNC SIGNAL GENERATOR
2 - CAMSHAFT POSITION SENSOR
3 - PULSE RING
4 - DISTRIBUTOR ASSEMBLY
BR/BEIGNITION CONTROL 8I - 11
CAMSHAFT POSITION SENSOR (Continued)

INSTALLATION
If engine has been cranked while distributor is
removed, establish the relationship between distribu-
tor shaft and number one piston position as follows:
Rotate crankshaft in a clockwise direction, as
viewed from front, until number one cylinder piston
is at top of compression stroke (compression should
be felt on finger with number one spark plug
removed). Then continue to slowly rotate engine
clockwise until indicating mark (Fig. 18) is aligned to
0 degree (TDC) mark on timing chain cover.
(1) Clean top of cylinder block for a good seal
between distributor base and block.
(2) Lightly oil the rubber o-ring seal on the distrib-
utor housing.
(3) Install rotor to distributor shaft.
(4) Position distributor into engine to its original
position. Engage tongue of distributor shaft with slot
in distributor oil pump drive gear. Position rotor to
the number one spark plug cable position.
(5) Install distributor holddown clamp and clamp
bolt. Do not tighten bolt at this time.
(6) Rotate the distributor housing until rotor is
aligned to CYL. NO. 1 alignment mark on the cam-
shaft position sensor (Fig. 19).(7) Tighten clamp holddown bolt (Fig. 20) to 22.5
N´m (200 in. lbs.) torque.
(8) Connect camshaft position sensor wiring har-
ness to main engine harness.
(9) Install distributor cap. Tighten mounting
screws.
(10) Refer to the following, Checking Distributor
Position.
Checking Distributor Position
To verify correct distributor rotational position, the
DRB scan tool must be used.
WARNING: WHEN PERFORMING THE FOLLOWING
TEST, THE ENGINE WILL BE RUNNING. BE CARE-
FUL NOT TO STAND IN LINE WITH THE FAN
BLADES OR FAN BELT. DO NOT WEAR LOOSE
CLOTHING.
(1) Connect DRB scan tool to data link connector.
The data link connector is located in passenger com-
partment, below and to left of steering column.
(2) Gain access to SET SYNC screen on DRB.
(3) Follow directions on DRB screen and start
engine. Bring to operating temperature (engine must
be in ªclosed loopº mode).
(4) With engine running atidle speed, the words
IN RANGE should appear on screen along with 0É.
This indicates correct distributor position.
(5) If a plus (+) or a minus (-) is displayed next to
degree number, and/or the degree displayed is not
zero, loosen but do not remove distributor holddown
clamp bolt. Rotate distributor until IN RANGE
appears on screen. Continue to rotate distributor
until achieving as close to 0É as possible. After
adjustment, tighten clamp bolt to 22.5 N´m (200 in.
lbs.) torque.
The degree scale on SET SYNC screen of DRB is
referring to fuel synchronization only.It is not
referring to ignition timing.Because of this, do
not attempt to adjust ignition timing using this
method. Rotating distributor will have no effect on
ignition timing. All ignition timing values are con-
trolled by powertrain control module (PCM).
After testing, install air cleaner assembly.
Fig. 20 Distributor Holddown Clamp
1 - CLAMP BOLT
2 - HOLDDOWN CLAMP
3 - DISTRIBUTOR HOUSING
BR/BEIGNITION CONTROL 8I - 13
DISTRIBUTOR (Continued)

REMOVAL - 8.0L
Two separate coil packs containing a total of five
independent coils are attached to a common mount-
ing bracket located above the right engine valve
cover (Fig. 26). The front and rear coil packs can be
serviced separately.
(1) Remove the secondary spark plug cables from
the coil packs. Note position of cables before removal.
(2) Disconnect the primary wiring harness connec-
tors at coil packs.(3) Remove the four (4) coil pack-to-coil mounting
bracket bolts for the coil pack being serviced (Fig.
26).
(4) Remove coil(s) from mounting bracket.
INSTALLATION
INSTALLATION - 5.9L
The ignition coil is an epoxy filled type. If the coil
is replaced, it must be replaced with the same type.
(1) Install the ignition coil to coil bracket. If nuts
and bolts are used to secure coil to coil bracket,
tighten to 11 N´m (100 in. lbs.) torque. If the coil
mounting bracket has been tapped for coil mounting
bolts, tighten bolts to 5 N´m (50 in. lbs.) torque.
(2) Connect all wiring to ignition coil.
INSTALLATION - 8.0L
(1) Position coil packs to mounting bracket (prima-
ry wiring connectors face downward).
(2) Install coil pack mounting bolts. Tighten bolts
to 10 N´m (90 in. lbs.) torque.
(3) Install coil pack-to-engine mounting bracket (if
necessary).
(4) Connect primary wiring connectors to coil
packs (four wire connector to front coil pack and
three wire connector to rear coil pack).
(5) Connect secondary spark plug cables to coil
packs. Refer to (Fig. 27) for correct cable order.
SPARK PLUG
DESCRIPTION
The 5.9L V-8 engines use resistor type spark plugs.
The 8.0L V-10 engine uses inductive type spark
plugs.
Spark plug resistance values range from 6,000 to
20,000 ohms (when checked with at least a 1000 volt
spark plug tester).Do not use an ohmmeter to
check the resistance values of the spark plugs.
Inaccurate readings will result.
OPERATION
To prevent possible pre-ignition and/or mechanical
engine damage, the correct type/heat range/number
spark plug must be used.
Always use the recommended torque when tighten-
ing spark plugs. Incorrect torque can distort the
spark plug and change plug gap. It can also pull the
plug threads and do possible damage to both the
spark plug and the cylinder head.
Remove the spark plugs and examine them for
burned electrodes and fouled, cracked or broken por-
celain insulators. Keep plugs arranged in the order
Fig. 25 Ignition CoilÐ5.9L V-8 HDC-Gas Engine
1 - COIL MOUNTING BOLTS
2 - IGNITION COIL
3 - COIL ELEC. CONNECTOR
4 - SECONDARY CABLE
Fig. 26 Ignition Coil PacksÐ8.0L V-10 Engine
8I - 16 IGNITION CONTROLBR/BE
IGNITION COIL (Continued)

cause of oil entry into that particular combustion
chamber.
ELECTRODE GAP BRIDGING
Electrode gap bridging may be traced to loose
deposits in the combustion chamber. These deposits
accumulate on the spark plugs during continuous
stop-and-go driving. When the engine is suddenly
subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 30).
This short circuits the electrodes. Spark plugs with
electrode gap bridging can be cleaned using standard
procedures.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 31). They may appear to be harmful, but
this is a normal condition caused by chemical addi-
tives in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy, but the deposits are easily removed. Spark
plugs with scavenger deposits can be considered nor-
mal in condition and can be cleaned using standard
procedures.
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation can also separate the insulator
from the center electrode (Fig. 32). Spark plugs with
this condition must be replaced.
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive
combustion chamber temperature. The center elec-
trode dissolves first and the ground electrode dis-
solves somewhat latter (Fig. 33). Insulators appear
relatively deposit free. Determine if the spark plug
has the correct heat range rating for the engine.
Determine if ignition timing is over advanced or if
other operating conditions are causing engine over-
heating. (The heat range rating refers to the operat-
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
temperature ranges. This depends upon the thick-
ness and length of the center electrodes porcelain
insulator.)
Fig. 29 Oil or Ash Encrusted
Fig. 30 Electrode Gap Bridging
1 - GROUND ELECTRODE
2 - DEPOSITS
3 - CENTER ELECTRODE
Fig. 31 Scavenger Deposits
1 - GROUND ELECTRODE COVERED WITH WHITE OR
YELLOW DEPOSITS
2 - CENTER ELECTRODE
8I - 18 IGNITION CONTROLBR/BE
SPARK PLUG (Continued)

(2) Prior to removing the spark plug, spray com-
pressed air around the spark plug hole and the area
around the spark plug. This will help prevent foreign
material from entering the combustion chamber.
(3) Remove the spark plug using a quality socket
with a rubber or foam insert.
(4) Inspect the spark plug condition. Refer to
Spark Plug Condition in the Diagnostics and Testing
section of this group.
CLEANING
The plugs may be cleaned using commercially
available spark plug cleaning equipment. After clean-
ing, file center electrode flat with a small point file or
jewelers file before adjusting gap.
CAUTION: Never use a motorized wire wheel brush
to clean spark plugs. Metallic deposits will remain
on spark plug insulator and will cause plug misfire.
INSTALLATION
Special care should be taken when installing spark
plugs into the cylinder head spark plug wells. Be
sure the plugs do not drop into the plug wells as elec-
trodes can be damaged.
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion resulting in a
change in the spark plug gap or a cracked porcelain
insulator.
When replacing the spark plug and ignition coil
cables, route the cables correctly and secure them in
the appropriate retainers. Failure to route the cables
properly can cause the radio to reproduce ignition
noise. It could cause cross ignition of the spark plugs
or short circuit the cables to ground.
(1) Start the spark plug into the cylinder head by
hand to avoid cross threading.
(2) Tighten spark plugs to 35-41 N´m (26-30 ft.
lbs.) torque.
(3) Install spark plug cables over spark plugs.
SPARK PLUG CABLE
DESCRIPTION
Spark plug cables are sometimes referred to as sec-
ondary ignition wires.
OPERATION
The spark plug cables transfer electrical current
from the ignition coil(s) and/or distributor, to individ-
ual spark plugs at each cylinder. The resistive spark
plug cables are of nonmetallic construction. The
cables provide suppression of radio frequency emis-
sions from the ignition system.
DIAGNOSIS AND TESTING - SPARK PLUG
CABLES
Cable routing is important on certain engines. To
prevent possible ignition crossfire, be sure the cables
are clipped into the plastic routing looms. Try to pre-
vent any one cable from contacting another. Before
removing cables, note their original location and
routing. Never allow one cable to be twisted around
another.
Check the spark plug cable connections for good
contact at the coil(s), distributor cap towers, and
spark plugs. Terminals should be fully seated. The
insulators should be in good condition and should fit
tightly on the coil, distributor and spark plugs. Spark
plug cables with insulators that are cracked or torn
must be replaced.
Clean high voltage ignition cables with a cloth
moistened with a non-flammable solvent. Wipe the
cables dry. Check for brittle or cracked insulation.
On 5.9L engines, spark plug cable heat shields are
pressed into the cylinder head to surround each
spark plug cable boot and spark plug (Fig. 36). These
shields protect the spark plug boots from damage
(due to intense engine heat generated by the exhaust
manifolds) and should not be removed. After the
spark plug cable has been installed, the lip of the
cable boot should have a small air gap to the top of
the heat shield (Fig. 36).
TESTING
When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer.
If an oscilloscope is not available, spark plug cables
may be tested as follows:
Fig. 36 Heat ShieldsÐ5.9L Engines
1 - AIR GAP
2 - SPARK PLUG BOOT HEAT SHIELD
8I - 20 IGNITION CONTROLBR/BE
SPARK PLUG (Continued)