Chrysler Stratus Convertible. Manual - part 234

IGNITION SYSTEM

TABLE OF CONTENTS

page

DESCRIPTION AND OPERATION

REMOVAL AND INSTALLATION

SPARK PLUGS AND CABLES—2.5L . . . . . . . . . . 5
IGNITION COIL—2.5L . . . . . . . . . . . . . . . . . . . . . 6
AUTOMATIC SHUTDOWN RELAY. . . . . . . . . . . . . 6
CRANKSHAFT POSITION SENSOR—2.5L . . . . . . 6

DISTRIBUTOR—2.5L . . . . . . . . . . . . . . . . . . . . . . 7
DISTRIBUTOR CAP—2.5L . . . . . . . . . . . . . . . . . . 9
DISTRIBUTOR ROTOR—2.5L. . . . . . . . . . . . . . . . 9
IGNITION SWITCH . . . . . . . . . . . . . . . . . . . . . . . . 9
LOCK KEY CYLINDER. . . . . . . . . . . . . . . . . . . . . 12
IGNITION INTERLOCK . . . . . . . . . . . . . . . . . . . . 13
LOCK CYLINDER HOUSING . . . . . . . . . . . . . . . . 13

SPECIFICATIONS

VEHICLE EMISSION CONTROL

INFORMATION LABEL . . . . . . . . . . . . . . . . . . . 13

FIRING ORDER . . . . . . . . . . . . . . . . . . . . . . . . . . 13
TORQUE SPECIFICATION . . . . . . . . . . . . . . . . . . 13
SPARK PLUG CABLE RESISTANCE—2.5L. . . . . 14
SPARK PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . . 14
IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . . 14

DESCRIPTION AND OPERATION

IGNITION SYSTEM

DESCRIPTION

NOTE: The 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 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

pickup,

camshaft

signal,

crankshaft signal and ignition coil.

OPERATION

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.

SPARK PLUGS PLATINUM

DESCRIPTION

The engine utilize platinum spark plugs. Refer to

the maintenance schedule.

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.

The spark plugs are double platinum and have a

recommended service life of 100,000 miles for normal
driving conditions per schedule A in this manual. The
spark plugs have a recommended service life of
75,000 miles for severe driving conditions per sched-
ule B in this manual. A thin platinum pad is welded
to both electrode ends as show in (Fig. 1). Extreme
care must be used to prevent spark plug cross
threading, mis-gaping and ceramic insulator damage
during plug removal and installation.

CAUTION: Cleaning of the platinum plug may dam-
age the platinum tip.

IGNITION SYSTEM

8D - 1

SPARK PLUG CABLES

DESCRIPTION

Spark Plug cables are sometimes referred to as

secondary ignition wires. They transfer electrical cur-
rent from the distributor or coil pack, to individual
spark plugs at each cylinder. The resistor type, non-
metallic spark plug cables provide suppression of
radio frequency emissions from the ignition system.

Check the spark plug cable connections for good

contact at the coil or coil pack and distributor cap
towers and at the spark plugs. Terminals should be

fully seated. The nipples and spark plug covers
should be in good condition. Nipples should fit tightly
on the coil or coil pack and distributor cap towers
and spark plug cover should fit tight around spark
plug insulators. Loose cable connections can cause
ignition malfunctions by permitting water to enter
the towers, corroding, and increasing resistance. To
maintain proper sealing at the terminal connec-
tions, the connections should not be broken
unless testing indicates high resistance, an
open circuit or other damage.

Clean high tension cables with a cloth moistened

with a non-flammable solvent and wipe dry. Check
for brittle or cracked insulation. Plastic clips in vari-
ous locations protect the cables from damage. When
the cables are replaced the clips must be used to pre-
vent damage to the cables.

IGNITION COIL—2.5L

DESCRIPTION

The ignition coil is located inside the distributor.

The distributor is mounted to the right end of the
engine block behind the thermostat housing (Fig. 3).

OPERATION

The 2.5L engine uses an epoxy type coil. The coils

are not oil filled. The windings are embedded in a
heat and vibration resistant epoxy compound.

On a 2.5L The PCM controls ignition timing by

turning on and off the transistor in the distributor.

Fig. 1 Platinum Pads

1 – APPLY ANTI-SEIZE COMPOUND HERE ONLY
2 – PLATINUM SPARK SURFACE

Fig. 2 Setting Spark Plug Electrode Gap

1 – TAPER GAUGE

Fig. 3 Ignition Coil—2.5L Engine

1 – HIGH TENSION TOWER
2 – IGNITION COIL

8D - 2

IGNITION SYSTEM

DESCRIPTION AND OPERATION (Continued)

By switching the ground path for the coil on and off,
the PCM adjusts ignition timing to meet changing
engine operating conditions.

The PCM operates the ignition coil through the

Auto Shutdown (ASD) relay. When the relay is ener-
gized by the PCM, battery voltage is connected to the
ignition coil positive terminal. The PCM will de-ener-
gize the ASD relay if it does not receive an input
from the distributor pick-up. Refer to Auto Shutdown
(ASD) Relay and Fuel Pump Relay in this section.

AUTOMATIC SHUTDOWN RELAY

DESCRIPTION

The ASD relay is located in the PDC (Fig. 4). The

inside top of the PDC cover has a label showing relay
and fuse identification.

OPERATION

The Automatic Shutdown (ASD) relay supplies bat-

tery voltage to the fuel injectors, generator field, elec-
tronic ignition coil and the heating elements in the
oxygen sensors.

Refer to the Wiring Diagrams for circuit informa-

tion.

The PCM controls the ASD relay by switching the

ground path for the solenoid side of the relay on and
off. The PCM turns the ground path off when the
ignition switch is in the Off position unless the O2
Heater Monitor test is being run. Refer to the

On-Board Diagnostics in the Emission Control sec-
tion. When the ignition switch is in On or Start, the
PCM momentarily turns on the ASD relay. While the
relay is on the PCM monitors the crankshaft and
camshaft position sensor signals to determine engine
speed and ignition timing (coil dwell). If the PCM
does not receive crankshaft and camshaft position
sensor signals when the ignition switch is in the Run
position, it will de-energize the ASD relay.

CRANKSHAFT POSITION SENSOR—2.5L

DESCRIPTION

The crankshaft sensor is located on the rear of the

transmission housing, above the differential housing
(Fig. 5). The sensor connector has a christmas tree
attached to the heater tube bracket. The bottom of
the sensor is positioned next to the drive plate.

OPERATION

The crankshaft position sensor (Fig. 6) detects slots

cut into the transmission driveplate extension. There
are 3 sets of slots. Each set contains 4 slots, for a
total of 12 slots (Fig. 7). Basic timing is set by the
position of the last slot in each group. Once the Pow-
ertrain Control Module (PCM) senses the last slot, it
determines crankshaft position (which piston will
next be at TDC) from the camshaft position sensor
input. The 4 pulses generated by the crankshaft posi-
tion sensor represent the 69°, 49°, 29°, and 9° BTDC
marks. It may take the PCM one engine revolution to
determine crankshaft position.

The PCM uses crankshaft position reference to

determine injector sequence, ignition timing and the
presence of misfire. Once the PCM determines crank-
shaft position, it begins energizing the injectors in
sequence.

Fig. 4 Power Distribution Center (PDC)

1 – POWER DISTRIBUTION CENTER
2 – POWERTRAIN CONTROL MODULE

Fig. 5 Crankshaft Position Sensor Location—Typical

1 – CRANKSHAFT POSITION SENSOR
2 – TRANSAXLE HOUSING

IGNITION SYSTEM

8D - 3

DESCRIPTION AND OPERATION (Continued)

CAMSHAFT POSITION SENSOR—2.5L

DESCRIPTION

The 2.5L engine is equipped with a camshaft

driven mechanical distributor, containing a shaft
driven distributor rotor. The distributor is also
equipped with an internal camshaft position (fuel
sync) sensor (Fig. 8). This sensor provides fuel injec-
tion synchronization and cylinder identification to
the PCM.

OPERATION

The PCM determines fuel injection synchronization

and cylinder identification from inputs provided by
the camshaft position sensor and crankshaft position
sensor. From the two inputs, the PCM determines
crankshaft position.

The camshaft position sensor contains a hall effect

device called a sync signal generator. This sync sig-
nal generator detects a rotating pulse ring (shutter)
on the distributor shaft. The pulse ring rotates 180
through the sync signal generator. Its signal is used
in conjunction with the crankshaft position sensor to
differentiate between fuel injection and spark events.
It is also used to synchronize the fuel injectors with
their respective cylinders.

When the leading edge of the shutter enters the

sync signal generator, the interruption of magnetic
field causes the voltage to switch high. This causes a
sync signal of approximately 5 volts.

When the trailing edge of the shutter leaves the

sync signal generator, the change of magnetic field
causes the sync signal voltage to switch low to 0
volts.

Since the shutter rotates at half crankshaft speed,

it may take 1 engine revolution during cranking for
the PCM to determine the position of piston number
6.

KNOCK SENSOR

DESCRIPTION

The knock sensor threads into the cylinder block.

Fig. 6 Crankshaft Position Sensor—Adjustable

1 – PUSH ON CLIP
2 – CRANKSHAFT POSITION SENSOR
3 – PAPER SPACER
4 – ADJUSTMENT HOLE

Fig. 7 Timing Slots

1 – TORQUE CONVERTER DRIVE PLATE
2 – SLOTS

Fig. 8 Camshaft Position Sensor—2.5L Engine

1 – PULSE RING
2 – SYNC SIGNAL GENERATOR
3 – DISTRIBUTOR

8D - 4

IGNITION SYSTEM

DESCRIPTION AND OPERATION (Continued)

Content .. 232 233 234 235 ..