²available manifold vacuum
²barometric pressure
²engine coolant temperature
²engine RPM
²intake air temperature (2.4L only)
²throttle position
The PCM also regulates the fuel injection system.
Refer to the Fuel Injection sections of Group 14.
IGNITION SYSTEM
NOTE: The 2.4, 3.0 and 3.3/3.8L 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 ignition system used on 2.4 and
3.3/3.8L engines is refered to as the Direct Ignition
System (DIS). The system's three main components
are the coil pack, crankshaft position sensor, and
camshaft position sensor. The crankshaft position
sensor and camshaft position sensor are hall effect
devices.
The 3.0L engine uses a distributor, crankshaft sen-
sor and ignition coil. The system's main components
are the distributor, distributor pickup, camshaft sig-
nal, crankshaft signal and ignition coil.
SPARK PLUGSÐ2.4/3.0L
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.
Replace spark plugs at the intervals recommended in
Group O - Lubrication and Maintenance.
Spark plugs that have low mileage may be cleaned
and reused if not otherwise defective, carbon or oil
fouled. Refer to the Spark Plug Condition section of
this group. After cleaning, file the center electrode
flat with a small flat point file or jewelers file. Adjust
the gap between the electrodes (Fig. 2) to the dimen-
sions specified in the chart at the end of this section.
Special care should be used when installing spark
plugs in the 2.4L cylinder head spark plug wells. Be
sure the plugs do not drop into the wells, damage to
the electrodes can occur.
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion resulting in a
change in the spark plug gap. Overtightening can
also damage the cylinder head. Tighten spark plugs
to 28 N´m (20 ft. lbs.) torque.SPARK PLUGSÐ3.3/3.8L
The 3.3/3.8L engines utilize platinum spark plugs.
Refer to the maintenance schedule in Group 0 of this
service manual.
Fig. 1 Powertrain Control Module
Fig. 2 Setting Spark Plug Electrode Gap
8D - 2 IGNITION SYSTEMNS
GENERAL INFORMATION (Continued)
engine is operating, the smaller the pulse width on
the oscilloscope.
By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu-
lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec-
ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in each
set represents 9 degrees before top dead center
(TDC).
The timing reference notches are machined to a
uniform width representing 13.6 degrees of crank-
shaft rotation. From the voltage pulse width the
PCM tells the difference between the timing refer-
ence notches and the 60 degree signature notch. The
60 degree signature notch produces a longer pulse
width than the smaller timing reference notches. If
the camshaft position sensor input switches from
high to low when the 60 degree signature notch
passes under the crankshaft position sensor, the
PCM knows cylinder number one is the next cylinder
at TDC.
The crankshaft position sensor mounts to the
engine block behind the generator, near the oil filter
(Fig. 8).
CAMSHAFT POSITION SENSOR
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 attaches to the rear
of the cylinder head (Fig. 2). A target magnet
attaches to the rear of the camshaft and indexes to
the correct position (Fig. 3). The target magnet has
four different poles arranged in an asymmetrical pat-
tern. As the target magnet rotates, the camshaft
position sensor senses the change in polarity (Fig. 4).
The sensor output switch switches from high (5.0
volts) to low (0.30 volts) as the target magnet rotates.
When the north pole of the target magnet passes
under the sensor, the output switches high. The sen-
sor output switches low when the south pole of the
target magnet passes underneath.
INTAKE AIR TEMPERATURE SENSORÐ2.4L
The intake air temperature sensor measures the
temperature of the air as it enters the engine. The
sensor supplies one of the inputs the PCM uses to
determine injector pulse width and spark advance.
The intake air temperature sensor threads into the
intake manifold (Fig. 5).
Fig. 2 Crankshaft Position Sensor
Fig. 3 Target Magnet
Fig. 4 Target Magnet Polarity
NSIGNITION SYSTEM 8D - 17
DESCRIPTION AND OPERATION (Continued)
(1) Install target magnet in end of camshaft.
Tighten mounting screw to 5.65 N´m (50 in. lbs.)
torque.
(2) Install a new O-ring on sensor.
(3) Install camshaft position sensor. Tighten sensor
mounting screws to 9.6 N´m (85 in. lbs.) torque.
(4) Attach engine harness connector to camshaft
position sensor.
(5) Install air cleaner inlet tube and filtered air
tube.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐ2.4/3.3/3.8L
REMOVAL
(1) Disconnect electrical connector from MAP sen-
sor (Fig. 12).
(2) Remove two screws holding sensor to the
intake manifold.
INSTALLATION
(1) Reverse the above procedure for installation.
THROTTLE POSITION SENSOR
Refer to Group 14, Fuel Injection Section, for
Removal/Installation.
ENGINE COOLANT TEMPERATURE SENSORÐ2.4L
The coolant sensor threads into the top of the ther-
mostat housing (Fig. 13). New sensors have sealant
applied to the threads.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
REFER TO GROUP 7- COOLING.
Fig. 10 Target Magnet
Fig. 11 Target Magnet Installation
Fig. 12 Map Absolute Pressure Sensor
Fig. 13 Engine Coolant Temperature SensorÐ2.4L
8D - 20 IGNITION SYSTEMNS
REMOVAL AND INSTALLATION (Continued)
3.0L ENGINE
INDEX
page page
DESCRIPTION AND OPERATION
CAMSHAFT POSITION SENSOR............ 23
FIRING ORDERÐ3.0L.................... 23
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR............................. 23
REMOVAL AND INSTALLATION
CRANKSHAFT POSITION SENSOR.......... 25
ENGINE COOLANT TEMPERATURE SENSORÐ
3.0L................................. 25
IGNITION COILÐ3.OL.................... 24
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐ3.0L........................ 24SPARK PLUG SERVICE................... 24
THROTTLE POSITION SENSOR............ 25
DISASSEMBLY AND ASSEMBLY
DISTRIBUTORÐ3.0L..................... 26
CLEANING AND INSPECTION
DISTRIBUTOR CAP...................... 26
DISTRIBUTOR ROTORÐ3.0L............... 27
SPECIFICATIONS
SPARK PLUG CABLE RESISTANCEÐ3.0L..... 27
SPARK PLUG........................... 27
TORQUE.............................. 27
DESCRIPTION AND OPERATION
FIRING ORDERÐ3.0L
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor reacts to absolute pressure in the
intake manifold and provides an input voltage to the
Powertrain Control Module (PCM). As engine load
changes, manifold pressure varies. The changes in
engine load cause the MAP sensors resistance to
change. The change in MAP sensor resistance results
in a different input voltage to the PCM.
The input voltage level supplies the PCM with
information relating to ambient barometric pressure
during engine start-up (cranking) and engine load
while its operating. Based on MAP sensor voltage
and inputs from other sensors, the PCM adjusts
spark advance and the air-fuel mixture.
CAMSHAFT POSITION SENSOR
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 3.0L 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. 1). This sensor provides fuel injec-
tion synchronization and cylinder identification to
the PCM.
The camshaft position sensor contains a hall effect
device callled 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.
SPARK PLUG WIRE ROUTINGÐ3.0L ENGINE
NSIGNITION SYSTEM 8D - 23
INSTALLATION
(1) Reverse the above procedure for installation.
ENGINE COOLANT TEMPERATURE SENSORÐ3.0L
The sensor is installed next to the thermostat
housing (Fig. 3).
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
REFER TO GROUP 7- COOLING.
REMOVAL
(1) With the engine cold, drain coolant until level
drops below cylinder head. Refer to Group 7, Cooling
System.
(2) Disconnect coolant sensor electrical connector.
(3) Remove coolant sensor.
INSTALLATION
(1) Install coolant sensor. Tighten sensor to 7 N´m
(60 in. lbs.) torque.
(2) Attach electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System.
CRANKSHAFT POSITION SENSOR
REMOVAL
(1) Raise and support vehicle.
(2) Disconnect crankshaft position sensor electrical
connector from the wiring harness connector (Fig. 4).
(3) Remove crankshaft position sensor retaining
bolt.
(4) Pull crankshaft position sensor straight up out
of the transaxle housing.
INSTALLATION
NOTE: If the removed sensor is to be reinstalled,
clean off the old spacer on the sensor face. A NEW
SPACER must be attached to the sensor face before
installation. If the sensor is being replaced, confirm
that the paper spacer is attached to the face of the
new sensor (Fig. 5).
(1) Install sensor in transaxle and push sensor
down until contact is made with the drive plate.
While holding the sensor in this position, and install
and tighten the retaining bolt to 11.9 N´m (105 in.
lbs.) torque.
(2) Raise and support vehicle.
(3) Connect crankshaft position sensor electrical
connector to the wiring harness connector.
THROTTLE POSITION SENSOR
Refer to Group 14, Fuel Injection Section, for
Removal/Installation.
Fig. 3 Manifold Absolute Pressure Sensor
Fig. 4 Crankshaft Position Sensor Connector
Fig. 5 Crankshaft Position Sensor and Spacer
NSIGNITION SYSTEM 8D - 25
REMOVAL AND INSTALLATION (Continued)
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
REMOVAL
(1) Disconnect electrical connector from MAP sen-
sor.
(2) Remove 2 screws holding sensor to intake man-
ifold (Fig. 9).
(3) Remove sensor from manifold.
INSTALLATION
Reverse the above procedure for installation.
ENGINE COOLANT TEMPERATURE SENSOR
The Engine Coolant Temperature (ECT) sensor is
located below the ignition coil (Fig. 10).
REMOVAL
(1) Drain cooling system until coolant level is
below sensor. Refer to Group 7, Cooling System.
(2) Remove electrical connector from coil (Fig. 11).
(3) Remove coil mounting screws.
(4) Rotate coil away from engine coolant tempera-
ture sensor.
(5) Disconnect electrical connector from engine
coolant temperature sensor.
(6) Remove sensor from engine.
INSTALLATION
(1) Tighten the sensor to 7 N´m (60 in. lbs.) torque.
(2) Connect electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System.
(4) Install coil. Tighten coil mounting screws to 12
N´m (105 in. lbs.) torque.
(5) Connect electrical connector to coil.
THROTTLE POSITION SENSOR
Refer to Group 14, Fuel Injection Section, for
Removal/Installation.
KNOCK SENSORÐ3.3/3.8L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 12).
Fig. 8 Camshaft Position Sensor and Spacer
Fig. 9 Manifold Absolute Pressure Sensor
Fig. 10 Engine Coolant Temperature Sensor
Fig. 11 Ignition Coil Removal
8D - 32 IGNITION SYSTEMNS
REMOVAL AND INSTALLATION (Continued)
INSTALLATION
Transfer speed control cable to replacement speed
control servo. Reverse the preceding operation.
SPEED CONTROL SWITCHES
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Remove airbag/horn pad from steering wheel,
refer to Group 8M, Restraint Systems for proper pro-
cedures.
(4) Disconnect wire connector from horn switch,
airbag, and speed control switches.
(5) Remove screws holding speed control switch to
airbag/horn pad (Fig. 11).
(6) Separate speed control switch from airbag/horn
pad.
INSTALLATION
Reverse the preceding operation.
STOP LAMP SWITCH
REMOVAL
Remove the switch from the bracket by depressing
the brake pedal and rotating the switch in a counter-
clockwise direction approximately 30 degrees. Pull
the switch rearward and remove from bracket. Dis-
connect wiring harness connector.
INSTALLATION
Before installing the switch, reset the adjustable
switch plunger by pulling on the plunger head until
the plunger reaches the end of its travel. A ratchet-
ing sound will be heard during this procedure.
Connect the wiring harness to the switch. Mount
the switch into the bracket by holding the switch
with the plunger facing forward in car. There is an
index key on the switch that mates with the bracket
slot at the top of the square hole. Align key and push
switch into square hole in bracket while depressing
the brake pedal. Once the switch is seated in the
hole, rotate clockwise approximately 30 degrees to
lock into place. The switch will automatically adjust
when the pedal is released. Pull back on the pedal to
assure correct adjustment.
SPEED CONTROL CABLE
REMOVAL
(1) Release hood latch and open hood.
(2) On vehicles with 3.3/3.8 L engine, remove air
cleaner resonator. Refer to Group 14, Fuel System for
proper procedure.
(3) Disconnect throttle and speed control cable
ends from throttle body (Fig. 8).
(4) Depress lock tabs holding speed control cable
casing to cable mount bracket (Fig. 12).
(5) Remove tie wrap holding vacuum line, throttle
cable, and speed control cable together.
(6) Remove nuts holding speed control cable case
to servo.
(7) Remove cable case from servo.
(8) Remove hairpin clip holding cable end to servo
diaphragm (Fig. 12).
(9) Remove speed control cable.
INSTALLATION
Reverse the preceding operation.
POWERTRAIN CONTROL MODULE
For Removal/Installation refer to Powertrain Con-
trol Module in Group 14, Fuel Injection System.
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE ORGINAL VEHICLES MILAGE. IF THIS
Fig. 10 Speed Control Servo
Fig. 11 Speed Control Switches
NSVEHICLE SPEED CONTROL SYSTEM 8H - 9
REMOVAL AND INSTALLATION (Continued)
STEP IS NOT DONE A DIAGONSTIC TROUBLE
CODE (DTC) MAY BE SET.
VACUUM RESEROIR
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove battery, Refer to Group 8B, for Battery
Removal/Installation
(3) Remove battery tray.
(4) Disconnect vacuum hoses from vacuum reser-
voir
INSTALLATION
(1) Connect vacuum hoses to vacuum reservoir.
(2) Install battery tray
(3) Install battery, Refer to Group 8B, for Battery
Removal/Installation.
(4) Connect negative cable to battery.
VEHICLE SPEED SENSOR
For Removal/Installation, refer to Vehicle Speed
Sensor in Group 14, Fuel Injections.
Fig. 12 Speed Control Cable
8H - 10 VEHICLE SPEED CONTROL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)