Ignition System - Jeep 1997 Grand Cherokee Service Manual

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GENERAL INFORMATION
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION AND OPERATION
AUTOMATIC SHUTDOWN (ASD) RELAY . . . . . . 3
CAMSHAFT POSITION SENSOR . . . . . . . . . . . . 3
CRANKSHAFT POSITION SENSOR-4.0L
ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CRANKSHAFT POSITION SENSOR-5.2L/5.9L
V-8 ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . 3
DISTRIBUTOR . . . . . . . . . . . . . . . . . . . . . . . . . . 2
ENGINE COOLANT TEMPERATURE SENSOR . . 4
IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . 3
IGNITION SWITCH AND KEY LOCK CYLINDER . 4

IGNITION SYSTEM

INTAKE MANIFOLD AIR TEMPERATURE
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
POWERTRAIN CONTROL MODULE (PCM) . . . . 2
SPARK PLUG CABLES
SPARK PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . 2
THROTTLE POSITION SENSOR . . . . . . . . . . . . 4
DIAGNOSIS AND TESTING
AUTOMATIC SHUTDOWN (ASD) RELAY TEST
CAMSHAFT POSITION SENSOR . . . . . . . . . . . . 7
CRANKSHAFT POSITION SENSOR . . . . . . . . . . 7
DISTRIBUTOR CAP . . . . . . . . . . . . . . . . . . . . . . 6
DISTRIBUTOR ROTOR
ENGINE COOLANT TEMPERATURE SENSOR . . 8
FAILURE TO START TEST . . . . . . . . . . . . . . . . . 5
IGNITION COIL TEST . . . . . . . . . . . . . . . . . . . . . 5
IGNITION TIMING . . . . . . . . . . . . . . . . . . . . . . . 7
INTAKE MANIFOLD AIR TEMPERATURE
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
MAP SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SPARK PLUG CABLES
GENERAL INFORMATION
INTRODUCTION
This group describes the ignition systems for 5.2L/
5.9L V-8 and 4.0L 6-cylinder engines.
On Board Diagnostics is described in Group 25,
Emission Control Systems.
Group 0, Lubrication and Maintenance, contains
general maintenance information (in time or mileage
intervals) for ignition related items. The Owner's
Manual also contains maintenance information.
IGNITION SYSTEM
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CONTENTS
page
SPARK PLUG CONDITIONS
TESTING FOR SPARK AT COIL . . . . . . . . . . . . . 4
REMOVAL AND INSTALLATION
AUTOMATIC SHUTDOWN (ASD) RELAY . . . . . 14
CAMSHAFT POSITION SENSOR . . . . . . . . . . . 15
CRANKSHAFT POSITION SENSOR-4.0L
ENGINE
CRANKSHAFT POSITION SENSOR-5.2L/5.9L
ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
DISTRIBUTOR-4.0L ENGINE . . . . . . . . . . . . . 17
DISTRIBUTOR-5.2L/5.9L ENGINES
ENGINE COOLANT TEMPERATURE SENSOR . 15
IGNITION COIL-4.0L ENGINE . . . . . . . . . . . . . 13
IGNITION COIL-5.2L/5.9L ENGINES . . . . . . . . 13
IGNITION SWITCH AND KEY CYLINDER . . . . . 20
INTAKE MANIFOLD AIR TEMPERATURE
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
POWERTRAIN CONTROL MODULE (PCM) . . . 20
SHIFTER/IGNITION INTERLOCK . . . . . . . . . . . 23
SPARK PLUG CABLES . . . . . . . . . . . . . . . . . . . 11
SPARK PLUGS
. 4 THROTTLE POSITION SENSOR
SPECIFICATIONS
ENGINE FIRING ORDER-4.0L 6-CYLINDER
ENGINE
ENGINE FIRING ORDER-5.2L/5.9L V-8
ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
IGNITION COIL RESISTANCE
IGNITION TIMING
SPARK PLUG CABLE RESISTANCE
SPARK PLUGS
TORQUE CHART . . . . . . . . . . . . . . . . . . . . . . . 23
VECI LABEL . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
DESCRIPTION AND OPERATION
IGNITION SYSTEM
The ignition systems used on 5.2L/5.9L V-8 and
4.0L 6-cylinder engines are basically identical. Simi-
larities and differences between the systems will be
discussed.
The ignition system is controlled by the powertrain
control module (PCM) on all engines.
The ignition system consists of:
• Spark Plugs
IGNITION SYSTEM
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8D - 1
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