1993 CHEVROLET DYNASTY service

REMOVAL
(1) Disconnect the coil to distributor ignition cable
(Fig. 4). (2) Disconnect the wiring harness connector from
the coil. (3) Remove ignition coil mounting screws.
INSTALLATION
(1) Install ignition coil onto the bracket. Tighten
the screws to 9.5 N Im (85 in. lbs.) torque. (2) Connect the wiring harness connector.
(3) Connect the coil to distributor ignition cable.
IGNITION COILÐ3.0L ENGINES
The ignition coil is located at the back of the intake
manifold (Fig. 5).
REMOVAL
(1) Remove air cleaner assembly.
(2) Disconnect ignition cable from coil.
(3) Disconnect wiring harness connector from coil.
(4) Remove coil mounting screws.
INSTALLATION
(1) Loosely install ignition coil on intake manifold.
Tighten the intake manifold fastener to 13 N Im(115
in. lbs.) torque. Tighten ignition coil bracket fasteners
to 10 N Im (96 in. lbs.) torque.
(2) Connect the wiring harness connector.
(3) Connect the coil to distributor ignition cable.
(4) Install the air cleaner assembly. Tighten the air
cleaner fasteners to 25 N Im (225 in. lbs.) torque.
SPARK PLUG SERVICE
When replacing the spark plug and coil cables, route
the cables correctly and secure them in the appropriate
retainers. Incorrectly routed cables can cause the radio
to reproduce ignition noise. It can also cause cross
ignition of the spark plugs or short circuit the cables to
ground.
SPARK PLUG REMOVAL
Always remove cables by grasping at boot, rotating
the boot 1/2 turn, and pulling straight back in a steady
motion. (1) Prior to removing the spark plug spray com-
pressed air around the spark plug hole and the area
around the spark plug. (2) Remove the spark plug using a quality socket
with a rubber or foam insert.
Fig. 3 Coolant Temperature SensorÐ3.0L Engine
Fig. 4 Ignition CoilÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines
Fig. 5 Ignition CoilÐ3.0L Engine
Ä IGNITION SYSTEMS 8D - 15

INSTALLATION
(1) Position distributor in engine. Make certain that
the O-ring is properly seated on distributor. If O-ring is
cracked or nicked, replace it with new one. (2) Carefully engage distributor drive with auxiliary
shaft drive. When distributor is installed properly,
rotor will be pointing toward cylinder block. If engine
has been cranked while distributor is removed,
establish proper relationship between the dis-
tributor shaft and Number 1 piston position as
follows: (a) Rotate the crankshaft until number one piston
is at top of compression stroke. Pointer on clutch
housing should be in line with the O(TDC)mark on
flywheel. (b) Rotate rotor to a position just ahead of the
number one distributor cap terminal. (c) Lower the distributor into the opening, engag-
ing distributor drive with drive on auxiliary shaft. With distributor fully seated on engine, rotor should
be under the cap number 1 tower.
(3) Install the distributor cap. Ensure all high ten-
sion wires snap firmly in the cap towers. (4) Install hold-down arm screw and finger tighten.
(5) Install splash shield.
(6) Connect distributor pick-up connector lead wire
at wiring harness connector. (7) Set ignition timing to specification. Refer to Ig-
nition Timing.
DISTRIBUTOR PICK-UPÐ2.2L TBI, 2.5L TBI AND
2.5L MPI ENGINES
REMOVAL
(1) Remove splash shield and cap. Refer to Distribu-
tor Removal. (2) Remove rotor from shaft (Fig. 15).
(3) Remove Hall effect pick-up assembly (Fig.
16).
INSTALLATION
(1) Place pick-up assembly into distributor housing
(Fig. 16). The distributor pick-up wires may be damaged
if not properly reinstalled. (2) Install rotor (Fig. 15).
(3) Install cap and splash shield. Refer to Distribu-
tor Installation.
DISTRIBUTOR SERVICEÐ3.0L ENGINE
REMOVAL
(1) Disconnect distributor connector from wiring
harness connector (Fig. 17).
Fig. 12 Splash ShieldÐ2.5L Engine
Fig. 13 Distributor Cap Retaining ScrewsÐ2.5L En- gine
Fig. 14 Distributor CapÐ2.5L Engine
8D - 18 IGNITION SYSTEMS Ä

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
SERVICEÐ2.5L TBI AND 3.0L ENGINES
(1) Remove vacuum hose and remove mounting
screws from sensor (Fig. 35, 36 and 37). (2) Remove wiring harness and remove sensor.
(3) Reverse the above procedure for installation.
Check that vacuum hose is attached to vacuum
source.
Fig. 30 Marks on Drive Gear and Shaft
Fig. 31 Drive Gear Roll Pin
Fig. 32 Drive Gear
Fig. 33 Distributor Shaft
8D - 22 IGNITION SYSTEMS Ä

tion (Fig. 16 or Fig. 17). The sensor generates pulses
that are the input sent to the PCM. The PCM inter-
prets the camshaft position sensor input (along with
the crankshaft position sensor input) to determine
crankshaft position. The PCM uses the crankshaft
position sensor input to determine injector sequence
and ignition timing.
The camshaft position sensor determines when a slot
in the camshaft gear passes beneath it (Fig. 18 or Fig.
19). When metal aligns with the sensor, voltage goes
low (less than 0.5 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 events. The camshaft position sensor is mounted to the top
of the timing case cover (Fig. 20 or Fig. 21). The bot-
tom of the sensor is positioned above the camshaft
sprocket. The distance between the bottom of
sensor and the camshaft sprocket is critical to
the operation of the system. When servicing the
camshaft position sensor, refer to the Turbo III, 3.3L and 3.8L Ignition SystemÐService Proce-
dures section in this Group.
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor senses slots cut into
the transaxle driveplate extension (Fig. 22 or Fig. 23).
On Turbo III, there ar e a 2 sets of slots. Each set
contains 4 slots, for a total of 8 slots (Fig. 24). On 3.3L
and 3.8L engines, there ar e a 3 sets of slots. Each set
contains 4 slots, for a total of 12 slots (Fig. 25).
Fig. 16 Camshaft Position SensorÐTurbo III Engine
Fig. 17 Camshaft Position SensorÐ3.3L and 3.8L Engines
Fig. 18 Camshaft GearÐTurbo III Engine
Fig. 19 Camshaft GearÐ3.3L and 3.8L Engines
Ä IGNITION SYSTEMS 8D - 29

tion timing from the crankshaft position sensor. Once
crankshaft position has been determined, the PCM
begins energizing the injectors in sequence.On Turbo III engines, the crankshaft position sensor
is located in the transaxle housing, below the throttle
body (Fig. 26). On 3.3L and 3.8L engines, the crank-
shaft position sensor is located in the transaxle hous-
ing (Fig. 27). The bottom of the sensor is positioned next to the
drive plate. The distance between the bottom of
sensor and the drive plate is critical to the op-
eration of the system. When servicing the crank-
shaft sensor, refer to the 3.3L Ignition
SystemÐService Procedures section in this
Group.IGNITION COIL
WARNING: THE DIRECT IGNITION SYSTEM GENER-
ATES APPROXIMATELY 40,000 VOLTS. PERSONAL
INJURY COULD RESULT FROM CONTACT WITH
THIS SYSTEM.
The 3.3L and 3.8L coil assembly consists of 3 coils
molded together (Fig. 28). The assembly is mounted
on the intake manifold. The 2.2L Turbo III coil as-
sembly consists of 2 coils molded together (Fig. 29).
The assembly is mounted at the front of the engine.
For all engines, the number of each coil appears on
the front of the coil pack.
High tension leads route to each cylinder from the
coil. The coil fires two spark plugs every power
stroke. One plug is the cylinder under compression,
the other cylinder fires on the exhaust stroke. The
PCM determines which of the coils to charge and fire
at the correct time. On 3.3L and 3.8L engines, coil one fires cylinders 1
and 4, coil two fires cylinders 2 and 5, coil three fires
cylinders three and six.
Fig. 28 Coil PackÐ2.2L Turbo III Engine
Fig. 29 Coil PackÐ3.3L and 3.8L Engines
Fig. 26 Crankshaft Position Sensor LocationÐTurbo III Engines
Fig. 27 Crankshaft Position Sensor LocationÐ3.3Land 3.8L Engines
Ä IGNITION SYSTEMS 8D - 31

Refer to the appropriate Powertrain Diagnostics Pro-
cedure Manual. Refer to the wiring diagrams section
for circuit information.
COOLANT TEMPERATURE SENSOR TEST
(1) With key off, disconnect wire connector from
coolant temperature sensor (Fig. 9).
(2) Connect one lead of ohmmeter to one terminal of
coolant temperature sensor. (3) Connect the other lead of ohmmeter to remaining
terminal of coolant temperature sensor. The ohmmeter
should read as follows;
² Engine/Sensor hot at normal operating temperature
around 200ÉF should read approximately 700 to 1,000
ohms.
² Engine/Sensor at room temperature around 70ÉF,
ohmmeter should read approximately 7,000 to 13,000
ohms. To test the coolant temperature sensor circuits,
refer to the DRBII scan tool and the appropriate
Powertrain Diagnostic Service manual.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to the appropriate Powertrain Diagnostic Pro-
cedure manual.
CRANKSHAFT POSITION SENSOR AND CAMSHAFT
POSITION SENSOR TESTS
Refer to the appropriate Powertrain Diagnostic Pro-
cedure manual.
Fig. 9 Coolant Temperature Sensor Test
8D - 38 IGNITION SYSTEMS Ä

2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMSÐSERVICE PROCEDURES INDEX
page page
Camshaft Position Sensor ServiceÐTurbo III Engine.42Camshaft Position SensorÐ3.3L and 3.8L Engines.43
Coolant Temperature SensorÐ3.3L and 3.8L Engines .............................. 39
Coolant Temperature SensorÐTurbo III ........ 39
Crankshaft Position SensorÐ3.3L and 3.8L Engines.42
Crankshaft Position SensorÐTurbo III Engine . . . 42
Idle RPM Test ........................... 41
Ignition Coil ServiceÐTurbo III Engine ........ 43 Ignition CoilÐ3.3L and 3.8L Engine
........... 43
Knock SensorÐTurbo III Engines ............ 40
Manifold Absolute Pressure (MAP) SensorÐ3.3L and 3.8L Engines ....................... 44
Manifold Absolute Pressure (MAP) SensorÐ Turbo III Engine ........................ 44
Powertrain Control Module (PCM) ............ 39
Spark Plug Cable Service .................. 40
Spark Plug Service ....................... 41
POWERTRAIN CONTROL MODULE (PCM)
REMOVAL
(1) Remove air cleaner duct or air cleaner assem-
bly. (2) Remove battery.
(3) Remove powertrain control module (PCM)
mounting screws (Fig. 1). (4) Remove 60-way connector from PCM. Remove
PCM.
INSTALLATION
(1) Connect 60-Way connector to PCM (Fig. 1).
(2) Install PCM on inside left front fender. Install
and tighten mounting screws. (3) Install the battery.
(4) Install air cleaner duct or air cleaner assembly.
COOLANT TEMPERATURE SENSORÐTURBO III
The coolant sensor threads into the thermostat
housing (Fig. 2).
REMOVAL
(1) Drain cooling system until coolant level is be-
low thermostat housing. Refer to Group 7, Cooling
System. (2) Remove air cleaner fresh air duct.
(3) Disconnect electrical connector from coolant
sensor. (4) Remove sensor from thermostat housing (Fig.
2).
INSTALLATION
(1) Install sensor. Tighten to 7 N Im (60 in. lbs.)
torque. (2) Connect electrical connector to coolant sensor
(3) Fill cooling system. Refer to Group 7, Cooling
System. (4) Install fresh air duct.
COOLANT TEMPERATURE SENSORÐ3.3L AND
3.8L ENGINES
The coolant temperature sensor is located below
the ignition coil (Fig. 3).
REMOVAL
(1) Drain cooling system until coolant level is be-
low coolant sensor. Refer to Group 7, Cooling System. (2) Remove electrical connector from coil (Fig. 4).
(3) Remove coil mounting screws.
(4) Rotate coil away from coolant temperature sen-
sor.
Fig. 1 Powertrain Control Module (PCM)
Fig. 2 Coolant Temperature SensorÐTurbo III
Ä IGNITION SYSTEMS 8D - 39

(5) Disconnect electrical connector from coolant
temperature sensor. (6) Remove sensor from engine.
INSTALLATION
(1) Tighten the coolant sensor to 7 N Im (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 Im (105 in. lbs.) torque.
(5) Connect electrical connector to coil.
KNOCK SENSORÐTURBO III ENGINES
The knock sensor is located on the intake manifold,
behind the PCV breather (Fig. 5).
REMOVAL
(1) Remove PCV breather.
(2) Remove harness connector from the knock sen-
sor. (3) Remove knock sensor.
INSTALLATION
(1) Install knock sensor. Tighten sensor to 9 N Im
(7 ft. lbs) torque. (2) Connect harness connector to sensor.
(3) Install PCV breather.
SPARK PLUG CABLE SERVICE
Clean high tension cables with a cloth moistened
with a non-flammable solvent. Wipe the cables dry.
Check for brittle or cracked insulation. When testing cables for punctures and cracks with
an oscilloscope, follow the instructions of the equip-
ment manufacturers.
CAUTION: Do not leave any one spark plug cable
disconnected any longer than necessary during test
or possible heat damage to catalytic converter will
occur. Total test time must not exceed ten minutes. If an oscilloscope is not available, cables can be
tested as follows: (1) With the engine not running, connect one end
of a test probe to a good ground. Use a probe made of
insulated wire and insulated alligator clips on each
end.
WARNING: THE ENGINE DIRECT IGNITION SYSTEM
GENERATES APPROXIMATELY 40,000 VOLTS.
PERSONAL INJURY COULD RESULT FROM CON-
TACT WITH THIS SYSTEM.
Fig. 3 Coolant Temperature SensorÐ3.3L and 3.3L Engine
Fig. 4 Ignition Coil Removal
Fig. 5 Knock SensorÐTurbo III Engine
8D - 40 IGNITION SYSTEMS Ä