NOTE: All engines use a fixed ignition timing sys-
tem. Basic ignition timing is not adjustable. All
spark advance is determined by the Powertrain
Control Module (PCM).

The ignition system used on these engines is

referred to as the Direct Ignition System (DIS). The
system’s four main components are the coils, crank-
shaft position sensor, spark plugs, and camshaft posi-
tion sensor. If equipped with the coil on plug ignition
system it utilizes an ignition coil for every cylinder
and is mounted directly over the each spark plug.

OPERATION - IGNITION SYSTEM

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 engine position from these sensors. The PCM
calculates injector sequence and ignition timing from
crankshaft & camshaft position. For a description of
both sensors, refer to Camshaft Position Sensor and
Crankshaft Position Sensor.

IGNITION CONTROL

8I - 1

SPECIFICATIONS

TORQUE

DESCRIPTION

N·m

Ft. Lbs.

In. Lbs.

SKREEM Module Screws

1.8

Ignition Switch Mounting

Nuts

3.4

Spark Plug 3.5l

Spark Plug 3.8L

17.5

Ignition Coils 3.5L

6.7

Ignition Coil Nuts 3.8L

11.8

105

Camshaft Position Sensor

Bolt 3.5L

106

Camshaft Position Sensor

Bolt 3.8L

14.1

125

Knock Sensor 3.5L

15.2

Knock Sensor 3.8L

SPARK PLUG

Engine

Spark Plug

Gap

Thread Size

3.5L

ZFR5LP-13G

0.048 TO 0.053

14mm (3/4 in.) reach

3.8L

re14PLP5

0.048 TO 0.053

14mm (3/4 in.) reach

SPARK PLUG CABLE RESISTANCE

3.8L

CABLE

Maximum Resistance

22.5K ohms

22.8K ohms

19.3K ohms

13.6K ohms

16.4K ohms

8I - 2

IGNITION CONTROL

IGNITION CONTROL (Continued)

CAMSHAFT POSITION
SENSOR

OPERATION

The camshaft position sensor contains a hall effect

device that provides cylinder identification to the
Powertrain Control Module (PCM) (1) (Fig. 1) and
(Fig. 2). The sensor generates pulses as groups of
notches on the camshaft sprocket pass underneath it.
The PCM keeps track of crankshaft rotation and
identifies each cylinder by the pulses generated by
the notches on the camshaft sprocket.

When metal aligns with the sensor, voltage goes

low (less than 0.3 volts). When a notch aligns with
the sensor, voltage spikes high (5.0 volts). As a group
of notches pass under the sensor, the voltage
switches from low (metal) to high (notch) then back

to low. The number of notches determine the amount
of pulses. If available, an oscilloscope can display the
square wave patterns of each timing event.

REMOVAL

3.5L

(1) Disconnect the negative battery cable.
(2) Remove air cleaner box.
(3) Unlock the camshaft sensor electrical connector

(Fig. 3).

(4) Disconnect the electrical connectors to the cam-

shaft sensor.

(5) Remove the mounting bolts.

Fig. 1 Camshaft Position Sensor—3.5L

Fig. 2 CAMSHAFT POSITION SENSOR — 3.8L

Fig. 3 CAM SENSOR LOCATION

Fig. 4 CAM SENSOR REMOVED

IGNITION CONTROL

8I - 3

(6) Remove camshaft sensor (Fig. 4).

3.8L

(1) Disconnect the negative battery cable.
(2) Unlock the camshaft sensor electrical connec-

tor.

(3) Disconnect the electrical connectors to the cam-

shaft sensor (Fig. 5).

(4) Loosen the mounting bolts (Fig. 6).
(5) Remove camshaft sensor (Fig. 7).
(6) Camshaft Position Sensor removed (Fig. 8).

Fig. 5 MOUNTING BOLT LOOSE

Fig. 6 CAMSHAFT POSITION SENSOR LOCATION

Fig. 7 SENSOR REMOVED

Fig. 8 CAMSHAFT POSITION SENSOR

8I - 4

IGNITION CONTROL

CAMSHAFT POSITION SENSOR (Continued)

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