Jeep Grand Cherokee WK. Manual - part 398
4.7L V-8 ENGINE
The 4.7L V-8 engine uses a separate ignition coil for each cylinder. The one-piece coil bolts directly to the cylinder
head. Rubber boots seal the secondary terminal ends of the coils to the top of all 8 spark plugs. A separate elec-
trical connector is used for each coil.
Because of coil design, spark plug cables (secondary cables) are not used. A distributor is not used with the 4.7L
engine.
Two knock sensors (one for each cylinder bank) are used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery voltage to each ignition coil.
The ignition system consists of:
•
8 Spark Plugs
•
8 Separate Ignition Coils
•
2 Knock Sensors
•
Powertrain Control Module (PCM)
•
Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft
Position, Throttle Position, 2 knock and MAP Sensors
5.7L V-8 ENGINE
For additional information, also refer to Ignition
Coil Description and Operation.
The 5.7L V-8 engine is equipped with 16 spark plugs.
Two plugs are used for each cylinder. The 5.7L is also
equipped with 8 separate and independent ignition
coils. The one-piece coil bolts directly to the cylinder
head cover and attaches the coils secondary output
terminal directly to a spark plug using a rubber boot
seal. Each coil is also equipped with a second output
terminal. This second terminal connects a conven-
tional spark plug cable directly to a spark plug on the
opposite cylinder bank. A separate primary electrical
connector is used for each coil.
Eight conventional spark plug cables are used with the
5.7L. These cables connect a coil on one cylinder
bank, directly to a spark plug on the opposite cylinder
bank. The cables are placed and routed in a special
plastic loom to keep them separated. This loom is
clipped to the intake manifold. To prevent a miss-
match of cables, a corresponding spark plug / coil
number is displayed on each plug cable: 1/6, 2/3, 4/7
and 5/8. These numbers (2) and (3) can also be found
on the top of the intake manifold (1) to the right of the throttle body.
Two knock sensors (one for each cylinder bank) are used to help control spark knock.
The 5.7L engine will not use a conventional distributor.
The ignition system consists of:
•
16 Spark Plugs (2 per cylinder)
•
8 Separate, Dual-Secondary Output, Ignition Coils
•
2 Knock Sensors
•
8 Secondary Ignition Cables
•
Powertrain Control Module (PCM)
•
Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft
Position, Throttle Position, 2 knock and MAP Sensors
8I - 12
IGNITION SYSTEM - SERVICE INFORMATION
WK