General Information; Introduction; Description And Operation - Chrysler Stratus RHD 1997 Interactive Electronic Service Manual

8D - 2 IGNITION SYSTEM

GENERAL INFORMATION

INTRODUCTION

This group describes the ignition systems for the
2.0, 2.4 and 2.5L engines.
On Board Diagnostics is described in Group 25 -
Emission Control Systems.
Group 0 - Lubrication and Maintenance, contains
general maintenance information for ignition related
items. The Owner's Manual also contains mainte-
nance information.

DESCRIPTION AND OPERATION

IGNITION SYSTEM
NOTE: The 2.0, 2.4, and 2.5L engines use a fixed
ignition timing system. Basic ignition timing is not
adjustable. All spark advance is determined by the
Powertrain Control Module (PCM).
The distributorless
2.0/2.4L engines is refered to as the Direct Ignition
System (DIS). Basic ignition timing is not adjust-
able. The system's three main components are the
coil pack, crankshaft position sensor, and camshaft
position sensor.
The crankshaft position sensor and camshaft posi-
tion sensor are hall effect devices. The camshaft posi-
tion sensor and crankshaft position sensor generate
pulses that are inputs to the PCM. The PCM deter-
mines crankshaft position from these sensors. The
PCM calculates injector sequence and ignition timing
from crankshaft position. For a description of both
sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor in this section.
The 2.5L engine uses a distributor, crankshaft sen-
sor and ignition coil. Basic ignition timing is not
adjustable. The system's main components are the
distributor, distributor
crankshaft signal and ignition coil.
The crankshaft position sensor and camshaft posi-
tion sensor are hall effect devices. The camshaft posi-
tion sensor and crankshaft position sensor generate
pulses that are inputs to the PCM. The PCM deter-
mines crankshaft position from these sensors. The
PCM calculates injector sequence and ignition timing
from crankshaft position. For a description of both
sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor in this section.
POWERTRAIN CONTROL MODULE (PCM)
The PCM regulates the ignition system (Fig. 1).
The PCM supplies battery voltage to the ignition coil
through the Auto Shutdown (ASD) Relay. The PCM
also controls the ground circuit for the ignition coil
ignition system used
pickup, camshaft signal,
POWER DISTRIBUTION CENTER
(2.0/2.4L). By switching the ground path for the coil
on and off, the PCM adjusts ignition timing to meet
changing engine operating conditions.
On a 2.5L The PCM controls ignition timing by
turning on and off a tranisistor in the distributor.
Refer to 2.5L Ignition Coil in this Group for more
information.
During the crank-start period the PCM maintains
spark advance at 9° BTDC. During engine operation
the following inputs determine the amount of spark
advance provided by the PCM.
• Intake air temperature
• Coolant temperature
• Engine RPM
• Intake manifold vacuum
• Knock sensor (2.0/2.4L Engines)
The PCM also regulates the fuel injection system.
Refer to the Fuel Injection sections of Group 14.
on
Fig. 1 Powertrain Control Module
SPARK PLUGS—2.0/2.4L
All engines use resistor spark plugs. They have
resistance values ranging from 6,000 to 20,000 ohms
when checked with at least a 1000 volt spark plug
tester.
Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.
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. An iso-
lated plug displaying an abnormal condition indicates
that a problem exists in the corresponding cylinder.
POWERTRAIN CON-
TROL MODULE
JA