1993 CHEVROLET DYNASTY oil

The coil's low primary resistance allows the PCM to
fully charge the coil for each firing.
COOLANT TEMPERATURE SENSOR
On 2.2L Turbo III engines, the coolant temperature
sensor is installed into the thermostat housing (Fig. 30).
On 3.3L and 3.8L engines, the coolant temperature sensor
is located next to the thermostat housing (Fig. 31).
The coolant temperature sensor provides an input
voltage to the powertrain control module (PCM). The
sensor is a variable resistance (thermistor) with a
range of -40ÉC to 130ÉC (-40ÉF to 265ÉF). As coolant
temperature varies, the sensor resistance changes,
resulting in a different input voltage to the PCM.
The PCM contains different spark advance schedules
for cold and warm engine operation. The schedules reduce
engine emission and improve driveability.
The PCM demands slightly richer air-fuel mixtures
and higher idle speeds until the engine reaches normal
operating temperature. The coolant sensor input is also used for cooling
fan control.
KNOCK SENSORÐTURBO III ENGINE
Turbo III engines use a knock sensor. The sensor gen-
erates a signal when spark detonation occurs in the
combustion chambers. The sensor is mounted on the in-
take manifold behind the PCV breather (Fig. 32). The
sensor provides input voltage used by the powertrain
control module (PCM) to modify spark advance and
boost schedules in order to eliminate detonation.
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 output voltage to change.
The change in MAP sensor output voltage results in
a different input voltage to the PCM.
The input voltage level supplies the PCM with infor-
mation relating to ambient barometric pressure during
engine start-up (cranking) and engine load while its op-
erating. The PCM uses this input along with inputs
from other sensors to adjust air-fuel mixture.
On Turbo III engines, the MAP sensor is mounted
to the front right fender (Fig. 33) On 3.3L and 3.8L
engines, the MAP sensor (Fig. 34) is mounted to the
side of the intake manifold, below the positive crank-
case ventilation (PCV) valve. The sensor is connected
to the PCM electrically.
AUTO SHUTDOWN (ASD) RELAY AND FUEL PUMP
RELAY
The powertrain control module (PCM) operates the
auto shutdown (ASD) relay and fuel pump relay
through one ground path. The PCM operates the re-
lays by switching the ground path on and off. Both
relays turn on and off at the same time.
Fig. 32 Knock SensorÐTurbo III Engine
Fig. 30 Coolant Temperature SensorÐTurbo III En- gines
Fig. 31 Coolant Temperature SensorÐ3.3L and 3.8LEngines
8D - 32 IGNITION SYSTEMS Ä

The ASD relay connects battery voltage to the fuel
injector and ignition coil. The fuel pump relay con-
nects battery voltage to the fuel pump and oxygen
sensor heating element. The PCM turns the ground path off when the igni-
tion switch is in the Off position. Both relays are off.
When the ignition switch is in the On or Crank po-
sition, the PCM monitors the camshaft position sen-
sor and crankshaft position sensor signals. From
these inputs, the PCM determines engine speed and
ignition timing (coil dwell). If the PCM does not re-
ceive a camshaft position sensor signal when the ig-
nition switch is in the Run position, it will de-
energize both relays. When the relays are de-
energized, battery voltage is not supplied to the fuel
injector, ignition coil, fuel pump and oxygen sensor
heating element. On AC, AG, AJ and AY models, the ASD relay and
fuel pump relay are located in the power distribution
center (Fig. 35, 36, 37, or 38). On AA and AP models, the ASD relay and fuel
pump relay are mounted on the drivers side fender
well, next to the strut tower (Fig. 39).
Fig. 33 MAP SensorÐTurbo III Engine
Fig. 34 Map SensorÐ3.3L and 3.8L Engines
Fig. 35 Power Distribution Center (PDC) (AC Body)
Fig. 36 Relay Identification (AC Body)
Fig. 37 Power Distribution Center (PDC) (AG and AJ Body)
Ä IGNITION SYSTEMS 8D - 33

2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMÐDIAGNOSTIC PROCEDURES INDEX
page page
Check Coil TestÐ3.3L and 3.8L Engines ...... 36
Check Coil TestÐTurbo III Engine ........... 35
Coolant Temperature Sensor Test ............ 38
Crankshaft Position Sensor and Camshaft Position Sensor Tests .......................... 38 Failure to Start Test
...................... 37
Failure to Start TestÐTurbo III Engine ........ 36
Manifold Absolute Pressure (MAP) Sensor Test . 38
Testing for Spark at CoilÐ3.3L and 3.8L Engines . 36
Testing for Spark at CoilÐTurbo III Engine ..... 35
TESTING FOR SPARK AT COILÐTURBO III ENGINE
WARNING: THE DIRECT IGNITION SYSTEM GENER-
ATES APPROXIMATELY 40,000 VOLTS. PERSONAL
INJURY COULD RESULT FROM CONTACT WITH
THIS SYSTEM.
The coil pack contains 2 independent coils. Each
coil must be checked individually.
CAUTION: Spark plug wire damage may occur if the
spark plug is moved more than 1/4 inch away from
the engine ground.
Remove the cable from number 1 spark plug. Insert
a clean spark plug into the spark plug boot, and
ground plug to the engine (Fig. 1).
CAUTION: Spark plug wire damage may occur if the
spark plug is moved more than 1/4 inch away from
the engine ground. Crank the engine and look for spark across the
electrodes of the spark plug. Repeat the above test
for the remaining cylinders. If there is no spark dur-
ing the cylinder tests, proceed to the failure to start
test. If one or more cylinders have irregular, weak, or
no spark, proceed to Check Coil Test.
CHECK COIL TESTÐTURBO III ENGINE
Cylinder s1&4,and2&3are grouped together.
(1) Remove the ignition cables and measure the
resistance of the cables. Resistance must be between
3,000 to 12,000 ohms per foot of cable. Replace any
cable not within tolerance. (2) Disconnect the electrical connector from the coil
pack (Fig. 2).
(3) Measure the primary resistance of each coil. At
the coil, connect an ohmmeter between the B+ pin and
the pin corresponding to the cylinders in question (Fig.
3). Resistance on the primary side of each coil should be
0.5-0.7 ohm. Replace the coil if resistance is not within
tolerance.
(4) Remove ignition cables from the secondary tow-
ers of the coil. Measure the secondary resistance of the
coil between the towers of each individual coil
Fig. 1 Testing For Spark
Fig. 2 Ignition Coil Electrical ConnectionÐTurbo III Engine
Fig. 3 Ignition Coil Terminal Identification
Ä IGNITION SYSTEMS 8D - 35

(Fig. 4). Secondary resistance should be 11,600 to
15,800 ohms. Replace the coil if resistance is not
within tolerance.
FAILURE TO START TESTÐTURBO III ENGINE
(1) Determine that sufficient battery voltage (12.4
volts nominal) is present for the cranking and igni-
tion systems. (2) Connect a voltmeter to the wiring harness coil
connector at the B+ pin (Fig. 5).
(3) Crank the engine for 5 seconds while monitor-
ing the voltage at the B+ connector terminal. If the
voltage remains near zero during the entire period of
cranking, check the auto shutdown relay and PCM.
Refer to DRBII scan tool and the appropriate Power-
train Diagnostic Procedures manual. Refer to Group
14 for description of On Board Diagnostics. (4) If voltage is at near-battery voltage, and drops
to zero after 1-2 seconds of cranking, check the cam-
shaft position sensor and crankshaft position sensor
and their circuits. Refer to the DRBII scan tool and
the appropriate Powertrain Diagnostic Procedure
manual. Refer to Group 14 for a description of On-
Board Diagnostics. (5) If voltage remains at near-battery voltage dur-
ing the entire 5 seconds, turn the key off, remove the PCM 60-way connector. Check the 60-way for any
terminals loose from the connector (push-out).
TESTING FOR SPARK AT COILÐ3.3L AND 3.8L
ENGINES
WARNING: THE ENGINE DIRECT IGNITION SYSTEM
GENERATES APPROXIMATELY 40,000 VOLTS. PER-
SONAL INJURY COULD RESULT FROM CONTACT
WITH THIS SYSTEM.
The coil pack contains 3 independent coils. Each coil
must be checked individually.
CAUTION: Spark plug wire damage may occur if the
spark plug is moved more than 1/4 inch away from the
engine ground.
Remove the cable from number 2 spark plug. Insert a
clean spark plug into the spark plug boot, and ground
plug to the engine (Fig. 1). Crank the engine and look for spark across the
electrodes of the spark plug. Repeat the above test for
the five remaining cylinders. If there is no spark
during all cylinder tests, proceed to the failure to start
test. If one or more tests indicate irregular, weak, or no
spark, proceed to Check Coil Test.
WARNING: THE DIRECT IGNITION SYSTEM GENER-
ATES APPROXIMATELY 40,000 VOLTS. PERSONAL
INJURY COULD RESULT FROM CONTACT WITH THIS
SYSTEM.
CHECK COIL TESTÐ3.3L 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. Each coil tower is labeled with the number of the
corresponding cylinder. (1) Remove the ignition cables and measure the
resistance of the cables. Resistance must be between
3,000 to 12,000 ohms per foot of cable. Replace any
cable not within tolerance. (2) Disconnect the electrical connector from the coil
pack (Fig. 6). (3) Measure the primary resistance of each coil. At
the coil, connect an ohmmeter between the B+ pin and
the pin corresponding to the cylinders in question (Fig.
7). Resistance on the primary side of each coil should be
0.5 - 0.7 ohm. Replace the coil if resistance is not within
tolerance. (4) Remove ignition cables from the secondary tow-
ers of the coil. Measure the secondary resistance of the
coil between the towers of each individual coil (Fig. 8).
Refer to the Coil Specifications Chart in the Specifica-
tions section of this group. Replace the coil if resistance
is not within tolerance.
Fig. 4 Checking Ignition Coil Secondary ResistanceÐTurbo III Engines
Fig. 5 Wiring Harness Coil ConnectorÐTurbo III Engine
8D - 36 IGNITION SYSTEMS Ä

FAILURE TO START TEST
This no-start test checks the camshaft position sen-
sor and crankshaft position sensor. The powertrain control module (PCM) supplies 8.0
volts to the camshaft position sensor and crankshaft
position sensor through one circuit. If the 8.0-volt
supply circuit shorts to ground, neither sensor will
produce a signal (output voltage to the PCM). When the ignition key is turned and left in the On
position , the PCM automatically energizes the auto shutdown (ASD) relay. However, the PCM de-energizes
the relay within one second because it has not received
a crankshaft position sensor signal indicating engine
rotation.
During cranking, the ASD relay will not energize
until the PCM receives a crankshaft signal. Secondly,
the ASD relay remains energized only if the PCM
senses a camshaft position sensor signal immediately
after detecting the crankshaft position sensor signal. (1) Check battery voltage. Voltage should approxi-
mately 12.66 volts or higher to perform failure to start
test. (2) Disconnect the harness connector from the coil
pack (Fig. 2). (3) Connect a test light to the B+ (battery voltage)
terminal of the coil electrical connector and ground.
The wire for the B+ terminal is dark green with a black
tracer. (4) Turn the ignition key to the ON position.The
test light should flash On and then Off. Do not turn
the Key to off position, leave it in the On position .
(a) If the test light flashes momentarily, the PCM
grounded the auto shutdown (ASD) relay. Proceed to
step 5. (b) If the test light did not flash, the ASD relay did
not energize. The cause is either the relay or one of
the relay circuits. Use the DRBII scan tool to test the
ASD relay and circuits. Refer to the appropriate
Powertrain Diagnostics Procedure Manual. Refer to
the wiring diagrams section for circuit information.
(5) Crank the engine. If the key was placed in the off
position after step 4, place the key in the On position
before cranking. Wait for the test light to flash once,
then crank the engine. (a) If the test light momentarily flashes during
cranking, the PCM is not receiving a camshaft posi-
tion sensor signal. Use the DRBII scan tool to test the
camshaft position sensor and sensor circuits. Refer to
the appropriate Powertrain Diagnostics Procedure
Manual. Refer to the wiring diagrams section for
circuit information. (b) If the test light did not flash during cranking,
unplug the camshaft position sensor connector. Turn
the ignition key to the off position. Turn the key to
the On position, wait for the test light to momen-
tarily flash once, then crank the engine. If the test
light momentarily flashes, the camshaft position
sensor is shorted and must be replaced. If the light
did not flash, the cause of the no-start is in either the
crankshaft position sensor/camshaft position sensor
8.0-volt supply circuit, or the crankshaft position
sensor 5-volt output or ground circuits. Use the
DRBII scan tool to test the crankshaft position sen-
sor and the sensor circuits.
Fig. 6 Ignition Coil Electrical Connection
Fig. 7 Ignition Coil Terminal Identification
Fig. 8 Checking Ignition Coil Secondary Resistance
Ä IGNITION SYSTEMS 8D - 37

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

(2) With engine running, move test probe along
entire length of all cables (approximately 0 to 1/8
inch gap). If punctures or cracks are present there
will be a noticeable spark jump from the faulty area
to the probe. Cracked, leaking or faulty cables should
be replaced. Use the following procedure when removing the
high tension cable from the spark plug. First, remove
the cable from the retaining bracket. Then grasp the
terminal as close as possible to the spark plug. Ro-
tate the cover (boot) slightly and pull straight back.
Do not use pliers and do not pull the cable at an
angle. Doing so will damage the insulation, cable
terminal or the spark plug insulator. Wipe spark
plug insulator clean before reinstalling cable
and cover. Resistance cables are identified by the words Elec-
tronic Suppression .
Use an ohmmeter to check cables for opens, loose
terminals or high resistance. (a) Remove cable from spark plug.
(b) Remove cable from the coil tower.
(c) Connect the ohmmeter between spark plug
end terminal and the coil end terminal. Resistance
should be within tolerance shown in the cable re-
sistance chart. If resistance is not within tolerance,
replace cable assembly. Test all spark plug cables
in same manner.
SPARK PLUG SERVICE
When replacing the spark plug cables, route the ca-
bles correctly and secure them in the appropriate re-
tainers. Incorrectly routed cables can cause the radio
to reproduce ignition noise. It can also cause cross ig-
nition 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. (3) Inspect the spark plug condition. Refer to
Spark Plug Condition in this section.
SPARK PLUG GAP ADJUSTMENT
Check the spark plug gap with a gap gauge. If the
gap is not correct, adjust it by bending the ground
electrode (Fig. 6).
SPARK PLUG INSTALLATION
(1) To avoid cross threading, start the spark plug
into the cylinder head by hand. (2) Tighten spark plugs to 28 N Im (20 ft. lbs.)
torque. (3) Install spark plug cables over spark plugs.
IDLE RPM TEST
WARNING: BE SURE TO APPLY PARKING BRAKE
AND/OR BLOCK WHEELS BEFORE PERFORMING
ANY ENGINE RUNNING TESTS.
Engine idle set rpmshould be tested and recorded
as it is when the vehicle is first brought into shop
for testing. This will assist in diagnosing complaints
of engine stalling, creeping and hard shifting on ve-
hicles equipped with automatic transaxle. Refer to the
Throttle Body Minimum Airflow procedures in Group
14.
IGNITION TIMING PROCEDURE
Ignition timing cannot be changed or set on Turbo
III, 3.3L or 3.8L engines. For diagnostic information,
refer to the DRBII scan tool and the appropriate
Powertrain Diagnostics Procedures manual.
CABLE RESISTANCE CHART
Fig. 6 Setting Spark Plug GapÐTypical
Ä IGNITION SYSTEMS 8D - 41