1993 DODGE TRUCK crankshaft sensor

•

IGNITION
SYSTEMS
8D
- 1
CONTENTS

page page
COMPONENT IDENTIFICATION/SYSTEM DIAGNOSTICS/SERVICE PROCEDURES
7
OPERATION
1
IGNITION SWITCH
25

COMPONENT REMOVAL/INSTALLATION
..... 18
SPECIFICATIONS
28

COMPONENT
IDENTIFICATION/SYSTEM OPERATION
INDEX
page

Automatic
Shut Down (ASD) Relay
1
Camshaft Position Sensor
2

Crankshaft Position Sensor
2

Distributors
3

Engine Coolant
Temperature
Sensor
...........
4

General
Information
1
page

Ignition
Coil
3
Intake
Manifold Charge
Air
Temperature
Sensor
. . 4

Manifold Absolute Pressure (MAP) Sensor
4
Powertrain
Control
Module (PCM)
. 5

Throttle
Position Sensor
5

GENERAL
INFORMATION
Throughout this group, references
are
made
to
par­
ticular vehicle models
by
alphabetical designation
or

by
the
particular vehicle nameplate.
A
chart showing a breakdown
of
alphabetical designations
is
included
in
the
Introduction group
at the
beginning
of
this
manual. 5.9L
gas
powered engines will
be
referred
to as ei­

ther: LDC (Light Duty Cycle),
or
HDC (Heavy Duty Cycle). This section
of the
group, Component Identifica­
tion/System Operation, will discuss ignition system operation
and
will identify ignition system compo­

nents.
For diagnostic procedures
and
adjustments, refer
to

the Diagnostics/Service Procedures section
of
this
group.
For removal
and
installation
of
ignition system
components, refer
to the
Component Removal/Instal­
lation section
of
this group. For other useful information, refer
to
On-Board
Di­

agnostics
in the
General Diagnosis sections
of
Group
14,
Fuel System
in
this manual. For operation
of the DRB II
Diagnostic Scan Tool,
refer
to the
appropriate Powertrain Diagnostic Proce­
dures service manual.
An Ignition specifications section
is
included
at the

end
of
this group.
A
general Maintenance Schedule (mileage intervals)
for
ignition related items
can be
found
in
Group
0,
Lubrication and Maintenance. This
schedule
can
also
be
found
in the
Owners Manual.

IGNITION
SYSTEMS
The ignition systems used
on all
engines
are
basi­
cally identical. Similarities
and
differences between
the systems will
be
discussed.
A sequential multi-port fuel injection system
is

used
on all gas
powered engines.
The ignition system
is
controlled
by the
powertrain
control module (PCM)
on all
engines.
The
PCM
was

formerly referred
to as the
SBEC
or
engine control­ ler.
The ignition system consists
of:

• Spark Plugs
• Ignition Coil
• Secondary Ignition Cables
• Ignition distributor. Contains rotor
and
camshaft
position sensor • Powertrain Control Module (PCM)
• Crankshaft Position Sensor

AUTOMATIC SHUT DOWN (ASD) RELAY
The automatic shut down (ASD) relay
is
located
in

the engine compartment (Fig.
1). As one of its
func­

tions,
the ASD
relay will supply battery voltage
to
the ignition coil.
The
ground circuit
for the
ASD
re­

lay
is
controlled
by the
powertrain control module (PCM).
The PCM
regulates
ASD
relay operation
by
switching
the
ground circuit on-and-off.

IGNITION
SYSTEMS

8D
- 2
IGNITION
SYSTEMS

•

A/C
CLUTCH RELAY STARTER RELAY
DATA LINK CONTROL

CONNECTOR
MODULE J9314-164
Fig.
1
Auto
Shut Down
Relay

CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the igni­
tion distributor (Fig. 2) on all engines.
Fig.
2 Camshaft Position
Sensor—
Typical

The camshaft position sensor contains a hall effect
device called a sync signal generator to generate a
fuel sync signal. This sync signal generator detects a
rotating pulse ring (shutter) on the distributor shaft.
The pulse ring rotates 180 degrees 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 re­ spective cylinders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following oc­

curs:
The interruption of magnetic field causes the
voltage to switch high resulting in a sync signal of approximately 5 volts.
When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following oc­

curs:
The change of the magnetic field causes the sync signal voltage to switch low to 0 volts. For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group. For removal and installation of this component, re­
fer to the Component Removal/Installation section of this group.

CRANKSHAFT
POSITION
SENSOR
The sensor is bolted to the top of cylinder block
near the rear of the right cylinder head (Fig. 3).

Fig.
3 Crankshaft Position Sensor—Typical

*
Engine speed and crankshaft position are provided
through the crankshaft position sensor. The sensor generates pulses that are the input sent to the pow­
ertrain control module (PCM). The PCM interprets
the sensor input to determine the crankshaft posi­
tion. The PCM then uses this position, along with other inputs, to determine injector sequence and ig­
nition timing.
The sensor is a hall effect device combined with an
internal magnet. It is also sensitive to steel within a
certain distance from it.

SENSOR
OPERATION-3.9L
ENGINE
The flywheel/drive plate has groups of notches at
its outer edge. On 3.9L V-6 engines, there are three sets of double notches and three sets of single
notches (Fig.
4).

The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input to the PCM.
The engine will not operate if the PCM does not re­
ceive a crankshaft position sensor input.
For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group.

•

IGNITION
SYSTEMS
8D - 3 For removal and installation of this sensor, refer to
the Component Removal/Installation section of this
group.
CRANKSHAFT
POSITION
SENSOR

NOTCHES- FLYWHEEL CRANKSHAFT
POSITION-
SENSOR

NOTCHES* .FLYWHEEL

J9314-88
—^^j^jV^
J9314-89

Fig.
4
Sensor
Operation—3.9L
Engine

SENSOR
OPERATION'-5.2U5.9L
ENGINES On 5.2L and 5.9L engines, the flywheel/drive plate
has 8 single notches, spaced every 45 degrees, at its outer edge (Fig. 5).
The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input to the PCM. For each engine revolution, there are 8
pulses generated on V-8 engines.
The engine will not operate if the PCM does not re­
ceive a crankshaft position sensor input. For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group.
For removal and installation of this component, re­
fer to the Component Removal/Installation section of
this group.

DISTRIBUTORS
For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group.

ALL
ENGINES All engines are equipped with a camshaft driven
mechanical distributor, containing a shaft driven dis­
tributor rotor. They are equipped with an internal camshaft position (fuel sync) sensor. This sensor pro­
vides fuel injection synchronization and cylinder identification.
Distributors do not have built in centrifugal or vac­
uum assisted advance. Base ignition timing and all
timing advance is controlled by the powertrain con­
trol module (PCM). Because ignition timing is con-
Fig.
5
Sensor
Opera tion—5.2L/5.9L
Engine

trolled by the PCM, base ignition timing is not adjustable on any of these engines.
The distributor is held to the engine in the conven­
tional method using a holddown clamp and bolt. Al­
though the distributor can be rotated, it will
have no effect on ignition timing.
All distributors contain an internal oil seal that
prevents oil from entering the distributor housing.
The seal is not serviceable.
For removal and installation of this component, re­
fer to the Component Removal/Installation section of
this group.

IGNITION
COIL
Battery voltage is supplied to the ignition coil pos­
itive terminal from the ASD relay. The powertrain control module (PCM) opens and
closes the ignition coil ground circuit for ignition coil operation. Base ignition timing is not adjustable on any
engine. By controlling the coil ground circuit, the
PCM is able to set the base timing and adjust the ig­ nition timing advance. This is done to meet changing engine operating conditions. The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat and vibration resistance that allows the ignition coil
to be mounted on the engine. • 3.9L/5.2L/5.9L LDC-Gas Engines: The coil is
mounted to a bracket that is bolted to the front of the right engine cylinder head (Fig. 6). This bracket is also used to mount the automatic belt tensioner.

•

IGNITION
SYSTEMS
80 - 7
DIAGNOSTICS/SERW1CE
PROCEDURES

INDEX

page

Automatic Shut Down (ASD) Relay
7
Camshaft Position
Sensor
Test
...............
7

Crankshaft Position
Sensor
Test
8

Distributor
Cap
8

Distributor
Rotor
8
Engine
Coolant Temperature
Sensor
Test
10

General
Information
7

Ignition
Coil
8

Ignition
Secondary
Circuit
Diagnosis
10

GENERAL
INFORMATION
This section
of the
group, Diagnostics/Service Pro­
cedures, will discuss basic ignition system diagnos­
tics
and
service adjustments. For system operation
and
component identification,
refer
to the
Component Identification/System Opera­
tion section
of
this group. For removal
or
installation
of
ignition system com­
ponents, refer
to the
Component Removal/Installa­
tion section
of
this group. For other useful information, refer
to
On-Board
Di­

agnostics
in the
General Diagnosis sections
of
Group
14,
Fuel System
in
this manual. For operation
of the DRB II
Diagnostic Scan Tool,
refer
to the
appropriate Powertrain Diagnostic Proce­
dures service manual.

AUTOMATIC SHUT DOWN
(ASD)
RELAY
Refer
to
Relays—Operation/Testing
in the
Group

14,
Fuel System section
of
this service manual.

CAMSHAFT POSITION SENSOR TEST
The camshaft position sensor
is
located
in the
dis­
tributor
on all
engines. To perform
a
complete test
of
this sensor
and its

circuitry, refer
to the DRB II
diagnostic scan tool.
Also refer
to the
appropriate Powertrain Diagnostics
Procedures manual.
To
test
the
sensor only, refer
to

the following: For this test,
an
analog (non-digital) voltmeter
is needed.
Do not
remove
the
distributor connector from
the
distributor. Using small paper clips, insert
them into
the
backside
of the
distributor wire har­ ness connector
to
make contact with
the
terminals.
Be sure that
the
connector
is not
damaged when
in­
serting
the
paper clips. Attach voltmeter leads
to

these paper clips. (1) Connect
the
positive (
+
)
voltmeter lead into
the sensor output wire. This
is at
done
the
distribu­ tor wire harness connector.
For
wire identification,
refer
to
Group
8W,
Wiring Diagrams.
page

Ignition
Timing
12

Intake Manifold Charge
Air
Temperature
Sensor
Test
12

Manifold Absolute Pressure (MAP)
Sensor
Test
. 12

Oxygen
Sensor
Tests
17
Powertrain Control Module (PCM)
............
14

Spark
Plug Secondary Cables
16

Spark
Plugs
............................
14

Throttle
Position
Sensor
Test
17

(2) Connect
the
negative
(-)
voltmeter lead into
the

ground wire.
For
wire identification, refer
to
Group
8W, Wiring Diagrams.
(3)
Set the
voltmeter
to the 15
Volt
DC
scale. (4) Remove distributor
cap
from distributor
(two

screws). Rotate (crank)
the
engine until
the
distribu­
tor rotor
is
pointed towards
the
rear
of
vehicle.
The

movable pulse ring should
now be
within
the
sensor
pickup.
(5) Turn ignition
key to ON
position. Voltmeter
should read approximately
5.0
volts.
(6)
If
voltage
is not
present, check
the
voltmeter
leads
for a
good connection.
(7)
If
voltage
is
still
not
present, check
for
voltage
at
the
supply wire.
For
wire identification, refer
to

Group
8W,
Wiring Diagrams.
(8)
If
voltage
is not
present
at
supply wire, check
for voltage
at
pin-7
of
powertrain control module (PCM) 60-way connector. Leave
the PCM
connector
connected
for
this test. (9)
If
voltage
is
still
not
present, perform vehicle
test using
the DRB II
diagnostic scan tool. (10)
If
voltage
is
present
at
pin-7,
but not at the

supply wire: (a) Check continuity between
the
supply wire.
This
is
checked between
the
distributor connector and pin-7
at the PCM. If
continuity
is not
present,
repair
the
harness
as
necessary. (b) Check
for
continuity between
the
camshaft
position sensor output wire
and
pin-44
at the PCM.
If continuity
is not
present, repair
the
harness
as
necessary. (c) Check
for
continuity between
the
ground cir­
cuit wire
at the
distributor connector
and
ground.
If continuity
is not
present, repair
the
harness
as
necessary. (11) While observing
the
voltmeter, crank
the en­

gine with ignition switch.
The
voltmeter needle should fluctuate between
0 and 5
volts while
the en­

gine
is
cranking. This verifies that
the
camshaft
po­
sition sensor
in the
distributor
is
operating properly
and
a
sync pulse signal
is
being generated.

8D
- 8
IGNITION
SYSTEMS

• If sync pulse signal is not present, replacement of
the camshaft position sensor is necessary. For removal or installation of ignition system com­
ponents, refer to the Component Removal/Installa­
tion section of this group.
For system operation and component identification,
refer to the Component Identification/System Opera­
tion section of this group.

CRANKSHAFT POSITION
SENSOR
TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB II diagnostic scan tool.
Also refer to the appropriate Powertrain Diagnostics
Procedures manual. To test the sensor only, refer to
the following: The sensor is located on the top of cylinder block
near the rear of right cylinder head (Fig. 1). (1) Near the rear of intake manifold, disconnect
sensor pigtail harness connector from main wiring
harness. Fig. 1 Crankshaft Position Sensor—Typical
(2) Place an ohmmeter across terminals B and C
(Fig. 2). Ohmmeter should be set to lK-to-lOK scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi­ cated.

DISTRIBUTOR
CAP INSPECTION Remove the distributor cap and wipe it clean with
a dry lint free cloth. Visually inspect the cap for
cracks, carbon paths, broken towers, or damaged ro­
tor button (Figs. 3 and 4). Also check for white de­
posits on the inside (caused by condensation entering VIEW LOOKING INTO

CPS
CONNECTOR
J938D-7

Fig. 2 Sensor Connector the cap through cracks). Replace any cap that dis­
plays charred or eroded terminals. The machined surface of a terminal end (faces toward rotor) will in­
dicate some evidence of erosion from normal opera­
tion. Examine the terminal ends for evidence of mechanical interference with the rotor tip. Fig. 3 Cap Inspection—External—Typical

DISTRIBUTOR ROTOR
Visually inspect the rotor (Fig. 5) for cracks, evi­
dence of corrosion, or the effects of arcing on the
metal tip. Also check for evidence of mechanical in­
terference with the cap. Some charring is normal on
the end of the metal tip. The silicone-dielectric-var­ nish-compound applied to the rotor tip for radio in­
terference noise suppression, will appear charred.
This is normal. Do not remove the charred com­ pound. Test the spring for insufficient tension. Re­
place a rotor that displays any of these adverse conditions.
IGNITION COIL

To perform a complete test of the ignition coil and
its circuitry, refer to the DRB II diagnostic scan tool.

8D
- 18
IGNITION
SYSTEMS

•
COMPONENT REMGWAL/INSTALLATION

INDEX

page

Automatic
Shut Down (ASD) Relay
18
Camshaft
Position
Sensor
, 18

Crankshaft Position
Sensor
18
Distributor
Service
20
Engine
Coolant Temperature
Sensor
20

General
Information
18
Ignition
Coil
21
page

Intake
Manifold Charge
Air
Temperature
Sensor
. 22

Manifold Absolute Pressure (MAP)
Sensor
..... 22

Oxygen
(02)
Sensor
22
Powertrain
Control
Module (PCM)
22

Spark
Plug Secondary Cables
24

Spark
Plugs
23

Throttle
Position
Sensor
(TPS)
24

GENERAL
INFORMATION
This section
of the
group, Component Removal/In­
stallation, will discuss
the
removal
and
installation
of ignition system components. For basic ignition system diagnostics
and
service
adjustments, refer
to the
Diagnostics/Service Proce­
dures section
of
this group. For system operation
and
component identification,
refer
to the
Component Identification/System Opera­
tion section
of
this group.

AUTOMATIC
SHUT DOWN
(ASb)
RELAY
The automatic shut down
(ASD)
relay
is
located
in

the engine compartment
(Fig. 1).
TORQUE CONVERTER
CLUTCH RELAY
A/C
CLUTCH RELAY STARTER RELAY

AUTO
SHUTDOWN RELAY FUEL PUMP RELAY DATA UNK
CONNECTOR POWERTRAIN
CONTROL
MODULE
J9314-164

Fig.
1
Auto
Shut Down
Relay
REMOVAL

(1) Disconnect negative battery cable
at
battery.

(2)
Remove
the
relay
by
pulling from connector.

INSTALLATION
(1) Check
the
terminals
in the
relay connector
for

corrosion
or
damage before installation.

(2)
Push
the
relay into
the
connector.

CAMSHAFT POSITION SENSOR
The camshaft position sensor
is
located
in the
dis­
tributor
(Fig. 2).
REMOVAL

Distributor removal
is not
necessary
to
remove
camshaft position sensor.

CAMSHAFT POSITION
SENSOR
SYNC

SIGNAL

GENERATOR
DISTRIBUTOR
ASSEMBLY
J9314-82

Fig.
2
Camshaft Position Sensor—Typical
(1) Disconnect negative battery cable
at
battery.

(2)
Remove distributor
cap
from distributor
(two

screws).
(3) Disconnect camshaft position sensor wiring
harness from main engine wiring harness.
(4) Remove distributor rotor from distributor shaft.

(5)
Lift
the
camshaft position sensor assembly from
the distributor housing
(Fig. 2).

INSTALLATION
(1) Install camshaft position sensor
to
distributor.
Align sensor into notch
on
distributor housing.
(2)
Connect wiring harness.
(3) Install rotor.
(4) Install distributor
cap.
Tighten mounting
screws.

CRANKSHAFT
POSITION SENSOR
REMOVAL The sensor
is
bolted
to the top of the
cylinder block
near
the
rear
of
right cylinder head
(Fig. 3).

•

Fig.
3 Crankshaft Position Sensor—Typical (1) Remove the spark plug cable loom and spark
plug cables from valve cover mounting stud at rear of right valve cover (Fig. 3). Position spark plug ca­
bles to top of valve cover.
(2) Disconnect 2 hoses at Exhaust Gas Recircula­
tion (EGR) valve. Note position of hoses at EGR valve before removal.
(3) Disconnect electrical connector and hoses at
electric EGR transducer (EET). Note position of
hoses at EET before removal.
(4) Remove 2 EGR valve mounting bolts and re­
move EGR valve. Discard old EGR gasket.
(5) Disconnect electrical connector at engine oil
pressure sending unit.
(6) To prevent damage to oil pressure sending unit,
a special tool, such as number C-4597 must be used (Fig. 4). Remove sending unit from engine.
(7) Loosen EGR tube mounting nut at intake man­
ifold.
(8) Remove 2 EGR tube mounting bolts at exhaust
manifold (Fig. 3) and remove EGR tube. Discard old
gasket at exhaust manifold.
(9) Disconnect crankshaft position sensor pigtail
harness from main wiring harness.
(10) Remove 2 sensor (recessed hex head) mount­
ing bolts (Fig. 3) and remove sensor.

INSTALLATION
(1) Position crankshaft position sensor to engine
and install mounting bolts. Tighten bolts to 8 N#m (70 in. lbs.) torque. (2) Connect main harness electrical connector to
sensor.
IGNITION
SYSTEMS
80-19

Fig.
4 Oil
Pressure
Sending
Unit—Removal/Installation (3) Clean the EGR tube and exhaust manifold (at
EGR tube mounting point) of any old gasket mate­

rial.
(4) Install a new gasket to exhaust manifold end of
EGR tube and install EGR tube to both manifolds.
Tighten mounting nut at intake manifold. Tighten 2 mounting bolts at exhaust manifold to 23 N#m (204 in. lbs.) torque.
(5) Coat the threads of the oil pressure sending
unit with thread sealant. Do not allow any of the
thread sealant to get into the sending unit opening, or the opening at the engine. Install sending unit to
engine and tighten to 14 N»m (130 in. lbs.) torque.
Install electrical connector to sending unit.
(6) Clean the intake manifold and EGR valve of
any old gasket material.
(7) Install a new EGR valve gasket at intake man­
ifold. (8) Install EGR valve to intake manifold. Tighten
2 bolts to 23 N«m (200 in. lbs.) torque.
(9) Position EET and install its electrical connec­
tor. Connect hoses between EGR valve and EET. Connect hose between main vacuum harness and
EET.
(10) Install spark plug cable loom and spark plug
cables to valve cover mounting stud.

8D
- 20
IGNITION
SYSTEMS

•
ENGINE
COOLANT
TEMPERATURE
SENSOR

WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOV­
ING THE COOLANT TEMPERATURE SENSOR. RE­
FER TO GROUP 7, COOLING.

REMOVAL
(1) Partially drain cooling system. Refer to Group
7, Cooling.

(2)
Disconnect electrical connector from sensor
(Fig. 5). Engines with air conditioning: When removing
the connector from sensor, do not pull directly on
wiring harness. Fabricate an L-shaped hook tool
from a coat hanger (approximately eight inches
long).
Place the hook part of tool under the connector
for removal. The connector is snapped onto the sen­ sor. It is not equipped with a lock type tab.
(3) Remove sensor from intake manifold.
Fig. 5 Coolant Temperature
Sensor—
Typical

INSTALLATION
(1) Install sensor.
(2) Tighten to 7 Nnn (5.5 ft. lbs.) torque.
(3) Connect electrical connector to sensor.
The sensor connector is symmetrical (not indexed).
It can be installed to the sensor in either direction. (4) Replace any lost engine coolant. Refer to Group
7, Cooling System.

DISTRIBUTOR
SERVICE

REMOVAL

CAUTION:
Base
ignition timing
is not
adjustable
on

any
engine. Distributors
do not
have
built
in
centrif­
ugal
or
vacuum assisted advance.
Base
ignition
timing
and
timing advance
are
controlled
by the
powertrain control module
(PCM).
Because
a
con­
ventional timing light can
not be
used
to
adjust
dis­

tributor
position
after
installation, note position
of
distributor before removal.

(1) Disconnect negative battery cable at battery.
(2) Remove distributor cap from distributor (two
screws).
(3) Mark the position of distributor housing in
relationship to engine or dash panel. This is done
to aid in installation. Before distributor is removed, the number one cyl­
inder must be brought to the top dead center (TDC)
firing position. (4) Attach a socket to the Crankshaft Vibration
Damper mounting bolt.
(5) Slowly rotate engine clockwise, as viewed from
front, until indicating mark on crankshaft vibration damper is aligned to 0 degree (TDC) mark on timing
chain cover (Fig. 6).
Fig. 6 Damper-To-Cover Alignment Marks—Typical (6) The distributor rotor should now be aligned to
the CYL. NO. 1 alignment mark (stamped) into the camshaft position sensor (Fig. 7). If not, rotate the
crankshaft through another complete 360 degree

turn.
Note the position of the number one cylinder spark plug cable (on the cap) in relation to rotor. Ro­
tor should now be aligned to this position.
(7) Disconnect camshaft position sensor wiring
harness from main engine wiring harness.
(8) Remove distributor rotor from distributor shaft. (9) Remove distributor holddown clamp bolt and
clamp (Fig. 8). Remove distributor from vehicle.
CAUTION: Do not
crank engine
with
distributor
re­
moved.
Distributor/crankshaft relationship
will
be

lost.