Dodge Dakota (R1). Manual — part 317
INSTALLATION - 3.9L/5.2L/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 - 4.7L
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install mounting stud nut and tighten to 8 N·m
(70 in. lbs.) torque.
(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube or
box.
SPARK PLUG
DESCRIPTION
All engines use resistor type spark plugs. 4.7L V-8
engines are equipped with “fired in suppressor seal”
type spark plugs using a copper core ground elec-
trode.
Because of the use of an aluminum cylinder head
on the 4.7L engine, spark plug torque is very critical.
To prevent possible pre-ignition and/or mechanical
engine damage, the correct type/heat range/number
spark plug must be used.
OPERATION
Remove the spark plugs and examine them for
burned electrodes and fouled, cracked or broken por-
celain insulators. Keep plugs arranged in the order
in which they were removed from the engine. A sin-
gle plug displaying an abnormal condition indicates
that a problem exists in the corresponding cylinder.
Replace spark plugs at the intervals recommended in
Lubrication and Maintenance.
Spark plugs that have low mileage may be cleaned
and reused if not otherwise defective, carbon or oil
fouled. Also refer to Spark Plug Conditions.
CAUTION: Never use a motorized wire wheel brush
to clean the spark plugs. Metallic deposits will
remain on the spark plug insulator and will cause
plug misfire.
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS
NORMAL OPERATING
The few deposits present on the spark plug will
probably be light tan or slightly gray in color. This is
evident with most grades of commercial gasoline
(Fig. 28). There will not be evidence of electrode
burning. On all engines except the 4.7L V-8, gap
growth will not average more than approximately
0.025 mm (.001 in) per 3200 km (2000 miles) of oper-
ation. On the 4.7L V-8, gap growth will not average
more than approximately .0015 in per 3200 km (2000
miles) of operation. Spark plugs that have normal
wear can usually be cleaned, have the electrodes
filed, have the gap set and then be installed.
Fig. 27 Ignition Coil Location—4.7L V–8 Engine
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
8I - 16
IGNITION CONTROL
AN
IGNITION COIL (Continued)
Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
for unleaded fuel. During combustion, fuel with MMT
causes the entire tip of the spark plug to be coated
with a rust colored deposit. This rust color can be
misdiagnosed as being caused by coolant in the com-
bustion chamber. Spark plug performance may be
affected by MMT deposits.
COLD FOULING/CARBON FOULING
Cold fouling is sometimes referred to as carbon
fouling. The deposits that cause cold fouling are basi-
cally carbon (Fig. 28). A dry, black deposit on one or
two plugs in a set may be caused by sticking valves
or defective spark plug cables. Cold (carbon) fouling
of the entire set of spark plugs may be caused by a
clogged air cleaner element or repeated short operat-
ing times (short trips).
WET FOULING OR GAS FOULING
A spark plug coated with excessive wet fuel or oil
is wet fouled. In older engines, worn piston rings,
leaking valve guide seals or excessive cylinder wear
can cause wet fouling. In new or recently overhauled
engines, wet fouling may occur before break-in (nor-
mal oil control) is achieved. This condition can usu-
ally be resolved by cleaning and reinstalling the
fouled plugs.
OIL OR ASH ENCRUSTED
If one or more spark plugs are oil or oil ash
encrusted (Fig. 29), evaluate engine condition for the
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.
Fig. 28 Normal Operation and Cold (Carbon) Fouling
1 - NORMAL
2 - DRY BLACK DEPOSITS
3 - COLD (CARBON) FOULING
Fig. 29 Oil or Ash Encrusted
Fig. 30 Electrode Gap Bridging
1 - GROUND ELECTRODE
2 - DEPOSITS
3 - CENTER ELECTRODE
AN
IGNITION CONTROL
8I - 17
SPARK PLUG (Continued)
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.)
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
34). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 2000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
REMOVAL
On 3.9L V-6 and 5.2/5.9L V-8 engines, spark plug
cable heat shields are pressed into the cylinder head
to surround each cable boot and spark plug (Fig. 35).
Fig. 31 Scavenger Deposits
1 - GROUND ELECTRODE COVERED WITH WHITE OR
YELLOW DEPOSITS
2 - CENTER ELECTRODE
Fig. 32 Chipped Electrode Insulator
1 - GROUND ELECTRODE
2 - CENTER ELECTRODE
3 - CHIPPED INSULATOR
Fig. 33 Preignition Damage
1 - GROUND ELECTRODE STARTING TO DISSOLVE
2 - CENTER ELECTRODE DISSOLVED
8I - 18
IGNITION CONTROL
AN
SPARK PLUG (Continued)
If removal of the heat shield(s) is necessary,
remove the spark plug cable and compress the sides
of shield for removal. Each shield is slotted to allow
for compression and removal. To install the shields,
align shield to machined opening in cylinder head
and tap into place with a block of wood.
4.7L V–8 Engine: Each individual spark plug is
located under each ignition coil. Each individual igni-
tion coil must be removed to gain access to each spark
plug. Refer to Ignition Coil Removal/Installation.
(1) Except 4.7L Engine: Prior to removing spark
plug, spray compressed air around spark plug hole
and area around spark plug. This will help prevent
foreign material from entering combustion chamber.
(2) 4.7L V–8 Engine: Prior to removing spark plug,
spray compressed air around base of ignition coil at
cylinder head. This will help prevent foreign material
from entering combustion chamber.
(3) Remove spark plug from cylinder head using a
quality socket with a rubber or foam insert. If
equipped with a 4.7L V-8 engine, also check condition
of coil o-ring and replace as necessary.
(4) Except 4.7L: Always remove spark plug or igni-
tion coil cables by grasping at the cable boot (Fig.
37). Turn the cable boot 1/2 turn and pull straight
back in a steady motion. Never pull directly on the
cable. Internal damage to cable will result.
(5) Inspect spark plug condition. Refer to Spark
Plug Conditions.
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
CAUTION: The 4.7L V–8 engine is equipped with
copper core ground electrode spark plugs. They
must be replaced with the same type/number spark
plug as the original. If another spark plug is substi-
tuted, pre-ignition will result.
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.
Except 4.7L Engine: 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 repro-
duce 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) Except 4.7L Engine: Tighten spark plugs to
35-41 N·m (26-30 ft. lbs.) torque.
(3) Except 4.7L Engine: Install spark plug cables
over spark plugs.
(4) 4.7L V–8 Engine: Tighten spark plugs to 27
N·m (20 ft. lbs.) torque.
(5) 4.7L V–8 Engine: Before installing coil(s), check
condition of coil o-ring and replace as necessary. To aid
in coil installation, apply silicone to coil o-ring.
(6) 4.7L V–8 Engine: Install ignition coil(s). Refer
to Ignition Coil Removal/Installation.
Fig. 34 Spark Plug Overheating
1 - BLISTERED WHITE OR GRAY COLORED INSULATOR
Fig. 35 Heat Shields—3.9/5.2/5.9L Engines
1 - AIR GAP
2 - SPARK PLUG BOOT HEAT SHIELD
AN
IGNITION CONTROL
8I - 19
SPARK PLUG (Continued)
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