Dodge Durango (HB). Manual - part 297

4. Remove coil mounting nut (2) from mounting stud.

5. Carefully pull up coil from cylinder head opening

with a slight twisting action.

6. Remove coil from vehicle.

4.7L V-8

An individual ignition coil (1) is used for each spark
plug. The coil fits into machined holes in the cylinder
head. A mounting stud/nut (3) secures each coil to the
top of the intake manifold . The bottom of the coil is
equipped with a rubber boot to seal the spark plug to
the coil. Inside each rubber boot is a spring. The
spring is used for a mechanical contact between the
coil and the top of the spark plug. These rubber boots
and springs are a permanent part of the coil and are
not serviced separately. An o-ring is used to seal the
coil at the opening into the cylinder head.

1. Depending on which coil is being removed, the

throttle body air intake tube or intake box may
need to be removed to gain access to coil.

2. Disconnect electrical connector (2) from coil by

pushing downward on release lock on top of con-
nector and pull connector from coil.

3. Clean area at base of coil with compressed air

before removal.

4. Remove coil mounting nut (3) from mounting stud.

5. Carefully pull up coil from cylinder head opening

with a slight twisting action.

6. Remove coil from vehicle.

IGNITION SYSTEM - SERVICE INFORMATION

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5.7L V-8

Before removing or disconnecting any spark plug
cables, note their original position. Remove cables
one-at-a-time. To prevent ignition crossfire, spark plug
cables MUST be placed in cable tray (routing loom)
into their original position.

An individual ignition coil (1) is used at each cylinder.
The coil mounts to the top of the valve cover with two
bolts (2). The bottom of the coil is equipped with a
rubber boot (3) to seal the spark plug to the coil.
Inside each rubber boot is a spring. The spring is used
for a mechanical contact between the coil and the top
of the spark plug.

1. Depending on which coil is being removed, the

throttle body air intake tube or intake box may
need to be removed to gain access to coil.

2. Unlock electrical connector (4) by moving slide lock

(1) first. Press on release lock (3) while pulling
electrical connector from coil.

3. Disconnect secondary high-voltage cable (2) from

coil with a twisting action.

4. Clean area at base of coil with compressed air

before removal.

5. Remove two mounting bolts (6) (note that mounting

bolts are retained to coil).

6. Carefully pull up coil from cylinder head opening

with a slight twisting action.

7. Remove coil from vehicle.

8. Before installing spark plug cables to either the

spark plugs or coils, or before installing a coil to a
spark plug, apply dielectric grease to inside of
boots.

INSTALLATION

3.7L V-6

1. Using compressed air, blow out any dirt or contaminants 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 coil mounting stud nut. Refer to torque specifications.

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IGNITION SYSTEM - SERVICE INFORMATION

5. Connect electrical connector to coil by snapping into position.

6. If necessary, install throttle body air tube.

4.7L V-8

1. Using compressed air, blow out any dirt or contaminants 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 coil mounting stud nut. Refer to torque specifications.

5. Connect electrical connector to coil by snapping into position.

6. If necessary, install throttle body air tube.

5.7L V-8

1. Using compressed air, blow out any dirt or contaminants from around top of spark plug.

2. Before installing spark plug cables to either the spark plugs or coils, or before installing a coil to a spark plug,

apply dielectric grease to inside of boots.

3. Position ignition coil into cylinder head opening and push onto spark plug. Twist coil into position.

4. Install 2 coil mounting bolts. Refer to torque specifications.

5. Connect electrical connector to coil by snapping into position.

6. Install cable to coil. To prevent ignition crossfire, spark plug cables MUST be placed in cable tray (routing loom)

into their original position. Refer to Spark Plug Cable Removal for a graphic.

7. If necessary, install throttle body air tube.

SENSOR-KNOCK

DESCRIPTION

The sensors are used only with 3.7L V-6, 4.7L V-8 and 5.7L V-8 engines. On 3.7L V-6 and 4.7L V-8 engines, the 2
knock sensors are bolted into the cylinder block under the intake manifold.

On 5.7L V-8 engines, 2 knock sensors are also used. These are bolted into each side of the cylinder block (outside)
under the exhaust manifold.

OPERATION

3.7L V-6 / 4.7L V-8 / 5.7L V-8 Engines Only

Two knock sensors are used; one for each cylinder bank. When the knock sensor detects a knock in one of the
cylinders on the corresponding bank, it sends an input signal to the Powertrain Control Module (PCM). In response,
the PCM retards ignition timing for all cylinders by a scheduled amount.

Knock sensors contain a piezoelectric material which constantly vibrates and sends an input voltage (signal) to the
PCM while the engine operates. As the intensity of the crystal’s vibration increases, the knock sensor output voltage
also increases.

The voltage signal produced by the knock sensor increases with the amplitude of vibration. The PCM receives the
knock sensor voltage signal as an input. If the signal rises above a predetermined level, the PCM will store that
value in memory and retard ignition timing to reduce engine knock. If the knock sensor voltage exceeds a preset
value, the PCM retards ignition timing for all cylinders. It is not a selective cylinder retard.

The PCM ignores knock sensor input during engine idle conditions. Once the engine speed exceeds a specified
value, knock retard is allowed.

Knock retard uses its own short term and long term memory program.

Long term memory stores previous detonation information in its battery-backed RAM. The maximum authority that
long term memory has over timing retard can be calibrated.

IGNITION SYSTEM - SERVICE INFORMATION

8I - 21

Short term memory is allowed to retard timing up to a preset amount under all operating conditions (as long as rpm
is above the minimum rpm) except at Wide Open Throttle (WOT). The PCM, using short term memory, can respond
quickly to retard timing when engine knock is detected. Short term memory is lost any time the ignition key is turned
off.

NOTE: Over or under tightening the sensor mounting bolts will affect knock sensor performance, possibly
causing improper spark control. Always use the specified torque when installing the knock sensors.

REMOVAL

3.7L V-6

The 2 knock sensors are bolted into the cylinder block
under the intake manifold (1) and (2).

NOTE: The left sensor is identified by an identifi-
cation tag (LEFT). It is also identified by a larger
bolt head. The Powertrain Control Module (PCM)
must have and know the correct sensor left/right
positions. Do not mix the sensor locations.

1. Disconnect knock sensor dual pigtail harness from

engine wiring harness. This connection is made
near rear of engine.

2. Remove intake manifold. Refer to Engine section.

3. Remove sensor mounting bolts (2). Note foam strip

on bolt threads. This foam is used only to retain the
bolts to sensors for plant assembly. It is not used
as a sealant. Do not apply any adhesive, sealant or
thread locking compound to these bolts.

4. Remove sensors from engine.

4.7L V-8

The two knock sensors (1) are bolted into the cylinder
block under the intake manifold (3).

1. Disconnect knock sensor dual pigtail harness from

engine wiring harness. This connection is made
near rear of engine.

2. Remove intake manifold. Refer to Engine section.

3. Remove sensor mounting bolts (2). Note foam strip

on bolt threads. This foam is used only to retain the
bolts to sensors for plant assembly. It is not used
as a sealant. Do not apply any adhesive, sealant or
thread locking compound to these bolts.

4. Remove sensors from engine.

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IGNITION SYSTEM - SERVICE INFORMATION

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