1993 CHEVROLET DYNASTY ESP

(8) Plug in the demagnetizing tool, keeping it at
least 2 feet away from the compass unit. (9) Slowly approach the center of the roof panel at
the windshield with the demagnetizing tool plugged
in.
² Contact the roof panel with the tip of the tool.
² Using slow sweeping motions of 1/2 inch between
sweeps
² Move the tool approximately 4 inches either side of
the centerline, and at least 11 inches back from the
windshield. (10) With the demagnetizing tool still energized,
slowly back away from the roof panel until the tip is
at least two feet from the roof before unplugging the
tool. (11) Recalibrate compass.
COMPASS DIAGNOSTICS
To place the unit into the diagnostics mode, turn
the vehicle ignition off. Depress the Comp/Temp but-
ton while turning on the ignition/run switch. The
display will then show DO. There are three tests that
can be performed when in the diagnostics mode.
Press the U.S./Metric button to choose test desired
(Fig. 5).
Test 1 (d1) determines the magnetic field strength
at the compass. The compass displays compensation
numbers which, correspond to the current magnetic
field strength at the compass. The letter N is dis-
played in the compass portion of the display. While a
number which, corresponds to the magnetic field
strength in the North/South direction is displayed.
The temperature portion of the display or the letter
W is displayed in the compass portion of the display. A number which, corresponds to the magnetic field
strength in the East/West direction is displayed in
the temperature portion of the display. For proper
compass operation the numbers should be between 1
and 14. A number of 7 or 8 is ideal (no vehicle mag-
netism) while numbers approaching 1 or 14 show
that the vehicle is highly magnetic. If the numbers
show that the vehicle is highly magnetic, perform
the demagnetized procedure in this Group and retest
for magnetism at compass. Test 2 (d2) checks the electronic circuits of the
compass, temperature. If the test passes d2 will be
displayed, and if the test fails F2 will be displayed.
Refer to Body Diagnostic Procedure Manual for fur-
ther testing procedures. Test 3 (d3) performs a walking segment test which,
sequentially puts different directions and numbers on
the display. If any segment fails, replace the compass
module.
SELF-DIAGNOSTIC TEST
(1) With the ignition switch in the OFF position si-
multaneously press the Comp/Temp button and the
US/Metric button. (2) Turn ignition switch ON.
(3) Continue to hold both buttons until the display
performs a walking segment test. This checks for
open or shorted segments. To repeat the test press
the Comp/Temp button. (4) Press the US/Metric button, all segments will
light for about 2 seconds. To repeat the test press the
Comp/Temp button. (5) Press the US/Metric button to return to normal
operation.
OVERHEAD CONSOLE REPLACEMENT
(1) Unscrew the mounting screw in sun glass bin
compartment (Fig. 6).
(2) Slide console forward toward windshield until
the console unhooks from roof bracket. (3) Disconnect wire harness from console.
(4) For installation reverse above procedures.
Fig. 5 Terminal Identification
Fig. 6 Overhead Console Mounting
Ä OVERHEAD CONSOLE 8C - 5

(12) Recalibrate compass.
COMPASS DIAGNOSTICS
To place the unit into the diagnostics mode, turn
the vehicle ignition off. Depress the Comp/Temp but-
ton while turning on the ignition/run switch. The
display will then show DO. There are 3 tests that
can be performed when in the diagnostics mode.
Press the U.S./Metric button to choose test desired
(Fig. 6 and 7). Test 1 (d1) determines the magnetic field strength
at the compass. The compass displays compensation
numbers which, correspond to the current magnetic
field strength at the compass. The letter N is dis-
played in the compass portion of the display. While a
number which, corresponds to the magnetic field
strength in the North/South direction is displayed.
The temperature portion of the display or the letter
W is displayed in the compass portion of the display.
A number which, corresponds to the magnetic field
strength in the East/West direction is displayed in
the temperature portion of the display. For proper
compass operation the numbers should be between 1
and 14. A number of 7 or 8 is ideal (no vehicle mag-
netism) while numbers approaching 1 or 14 show
that the vehicle is highly magnetic. If the numbers
show that the vehicle is highly magnetic, perform
the demagnetized procedure in this Group and retest
for magnetism at compass. If the compass is not re-
ceiving information from the CCD bus, F1 will be
displayed 15 seconds after this test is requested. Re-
fer to AG and AJ Body Diagnostic Procedure Manual
for further testing procedures. Test 2 (d2) checks the electronic circuits of the
compass, temperature, and CCD bus. If the test
passes d2 will be displayed, and if the test fails F2
will be displayed. Refer to AG and AJ Body Diagnos-
tic Procedure Manual for further testing procedures. Test 3 (d3) performs a walking segment test which,
sequentially puts different directions and numbers on
the display. If any segment fails, replace the compass
module.
Fig. 6 Terminal Identification
8C - 18 OVERHEAD CONSOLE Ä

(3) Plug the demagnetizing tool into a standard
110/115 volt AC outlet, keeping the demagnetizing
tool at least 12 inches away from the compass area
when plugging it in. (4) Slowly approach the console mounting screw
with the plastic coated tip of the tool for at least 2
seconds. (5) With the demagnetizing tool still energized,
slowly back it away from the screw until the tip is at
least 12 inches from the screw head. (6) After you have pulled at least 12 inches from
the last screw, remove the demagnetizer tool from in-
side of the vehicle and disconnect it from the electri-
cal outlet. (7) Place an 8 1/2 X 11 inch piece of paper length-
wise on the roof of vehicle directly above compass.
The purpose of the paper is to protect the roof panel
from scratches and define the area to be demagne-
tized. (8) Plug in the demagnetizing tool, keeping it at
least 2 feet away from the compass unit. (9) Slowly approach the center of the roof panel at
the windshield with the demagnetizing tool plugged
in. (10) Contact the roof panel with the tip of the tool
and using slow sweeping motions of 1/2 inch between sweeps. Move the tool approximately 4 inches either
side of the centerline and at least 11 inches back
from the windshield. (11) With the demagnetizing tool still energized,
slowly back away from the roof panel until the tip is
at least 2 feet from the roof before unplugging the
tool. (12) Recalibrate compass.
COMPASS DIAGNOSTICS
To place the unit into the diagnostics mode, turn
the vehicle ignition off. Depress the Comp/Temp but-
ton while turning on the ignition/run switch. The
display will then show DO. There are 3 tests that
can be performed when in the diagnostics mode.
Press the U.S./Metric button to choose test desired.
Refer to Fig. 4 and 5.
Test 1 (d1) determines the magnetic field strength
at the compass. The compass displays compensation
numbers which, correspond to the current magnetic
field strength at the compass. The letter N is dis-
played in the compass portion of the display. While a
number which, corresponds to the magnetic field
strength in the North/South direction is displayed.
The temperature portion of the display or the letter
W is displayed in the compass portion of the display.
A number which, corresponds to the magnetic field
strength in the East/West direction is displayed in
the temperature portion of the display. For proper
compass operation the numbers should be between 1
and 14. A number of 7 or 8 is ideal (no vehicle mag-
netism) while numbers approaching 1 or 14 show
that the vehicle is highly magnetic. If the numbers
show that the vehicle is highly magnetic, perform
the demagnetized procedure in this Group and retest
for magnetism at compass. If the numbers show that
the vehicle is highly magnetic, perform the demagne-
tizing procedure in this section and retest for magne-
tism at compass. The compass is not on the CCD bus,
if not functioning properly, refer to the Overhead
Console and Thermometer diagnosis. Test 2 (d2) checks the electronic circuits of the
compass, temperature, and CCD bus. If the test
passes d2 will be displayed, and if the test fails F2
will be displayed. Refer to AG and AJ Body Diagnos-
tic Procedure Manual for further testing procedures.
Fig. 3 Variance Zone MapFig. 4 Overhead Console Connector
Ä OVERHEAD CONSOLE 8C - 23

IGNITION SYSTEMS
CONTENTS
page page
2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNITION SYSTEMSÐDIAGNOSTIC PROCEDURES
..... 11
2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNI- TION SYSTEMSÐSERVICE PROCEDURES . 14
2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNI- TION SYSTEMSÐSYSTEM OPERATION .... 1
2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMÐDIAGNOSTIC PROCEDURES
.... 35
2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMÐSYSTEM OPERATION ......... 24
2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMSÐSERVICE PROCEDURES ...... 39
IGNITION SWITCH ...................... 45
SPECIFICATIONS ....................... 47
GENERAL INFORMATION
Throughout this group, references are made to par-
ticular vehicles by letter designation. A chart ex-
plaining the designations appears in the Introduction
Section of this manual.
2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNITION SYSTEMSÐSYSTEM OPERATION
INDEX
page page
Auto Shutdown (ASD) Relay and Fuel Pump Relay . 8
Coolant Temperature Sensor ................. 7
Distributor Cap ........................... 1
Distributor Pick-UpÐ3.0L Engine .............. 7
Distributor Pick-UpÐPCM Input ............... 6
General Information ........................ 1 Ignition Coil
.............................. 9
Manifold Absolute Pressure (MAP) Sensor ...... 8
Powertrain Control Module (PCM) ............. 6
Rotor .................................. 2
Spark Plug Cables ........................ 2
Spark Plugs ............................. 3
GENERAL INFORMATION
This section describes the ignition systems of the
2.2L TBI, 2.5L TBI, 2.5L MPI (flexible fuel AA-body)
and 3.0L engines. The Fuel Injection sections of Group 14 explain On
Board Diagnostics. Group 0, Lubrication and Maintenance, contains
general maintenance information for ignition related
items. The Owner's Manual also contains mainte-
nance information.
DISTRIBUTOR CAP
Remove the distributor cap and inspect the inside
for flash over, cracking of carbon button, lack of
spring tension on carbon button, cracking of cap, and
burned, worn terminals (Fig. 1). Also check for bro-
ken distributor cap towers. If any of these conditions
are present the distributor cap and/or cables should
be replaced. When replacing the distributor cap, transfer cables
from the original cap to the new cap one at a time.
Ensure each cable is installed into the corresponding tower of the new cap. Fully seat the wires into the
towers. If necessary, refer to the appropriate engine
firing order diagram (Fig. 2 or Fig. 3).
Fig. 1 Distributor Cap Inspection
Ä
IGNITION SYSTEMS 8D - 1

When testing secondary cables for punctures and
cracks with an oscilloscope follow the equipment
manufacturers instructions. If an oscilloscope is not available, secondary cables
can be tested as follows:
CAUTION: Do not leave any one spark plug cable
disconnected any longer than necessary during test-
ing. Excessive heat could damage the catalytic con-
verter. Total test time must not exceed ten minutes.
(a) With the engine not running, connect one end
of a test probe to a good ground. Use a probe made of
insulated wire with insulated alligator clips on each
end. (b) 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. Check the coil cable the same way.
Replace cracked, leaking or faulty cables.
When replacing cables, install the new high
tension cable and nipple assembly over cap or
coil tower. When entering the terminal into the
tower, push lightly, then pinch the large diam-
eter of nipple to release air trapped between the
nipple and tower. Continue pushing on the cable
and nipple until cables are properly seated in the
cap towers. A snap should be heard as terminal
goes into place. Use the same procedure to install cable in coil tower.
Wipe the spark plug insulator clean before reinstalling
cable and cover. 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 ter-
minal as close as possible to the spark plug. Rotate the
cover and pull the cable straight back. Pulling on the
cable itself will damage the conductor and termi-
nal connection. 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 in-
sulator. Wipe spark plug insulator clean before
reinstalling cable and cover. Resistance type cable is identified by the words
Electronic Suppression printed on the cable jacket.
Use an ohmmeter to check resistance type cable for
open circuits, loose terminals or high resistance as
follows: (a) Remove cable from spark plug.
(b) Lift distributor cap from distributor with
cables intact. Do not remove cables from cap. The
cables must be removed from the spark plugs. (c) Connect the ohmmeter between spark plug end
terminal and the corresponding electrode inside the
cap, make sure ohmmeter probes are in good contact.
Resistance should be within tolerance shown in the cable resistance chart. If resistance is
not within tolerance, remove cable at cap tower
and check the cable. If resistance is still not within
tolerance, replace cable assembly. Test all spark
plug cables in same manner.
To test coil to distributor cap high tension cable,
remove distributor cap with the cable intact. Do not
remove cable from the cap. Connect the ohmmeter
between center contact in the cap and remove the ca-
ble at coil tower and check cable resistance. If resis-
tance is not within tolerance, replace the cable.
SPARK PLUGS
Resistor spark plugs are used in all engines and
have resistance values of 6,000 to 20,000 ohms when
checked with at least a 1000 volt tester. 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 indi-
cates that a problem exists in the corresponding
cylinder. Replace spark plugs at the intervals recom-
mended in Group O. Undamaged low milage spark plugs can be cleaned
and reused. Refer to the Spark Plug Condition sec-
tion of this group. After cleaning, file the center elec-
trode flat with a small point file or jewelers file.
Adjust the gap between the electrodes (Fig. 6) to the
dimensions specified in the chart at the end of this
section. Always tighten spark plugs to the specified torque.
Over tightening can cause distortion and change
spark plug gap. Tighten spark plugs to 28 N Im (20 ft.
lbs.) torque.
SPARK PLUG CONDITION
NORMAL OPERATING CONDITIONS
The few deposits present will be probably light tan
or slightly gray in color with most grades of commer-
cial gasoline (Fig. 7). There will not be evidence of
electrode burning. Gap growth will not average more
than approximately 0.025 mm (.001 in) per 1600 km
(1000 miles) of operation. Spark plugs that have nor-
mal wear can usually be cleaned, have the electrodes
filed and regapped, and then reinstalled. Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
CABLE RESISTANCE CHART
Ä IGNITION SYSTEMS 8D - 3

tance. The cables provide suppression of radio fre-
quency emissions from the ignition system.Check the spark plug cable connections for good
contact at the coil and distributor cap towers and at
the spark plugs. Terminals should be fully seated.
The nipples and spark plug covers should be in good
condition. Nipples should fit tightly on the coil and
distributor cap towers and spark plug cover should
fit tight around spark plug insulators. Loose cable
connections can cause ignition malfunctions by per-
mitting water to enter the towers, corroding, and in-
creasing resistance.
SPARK PLUGS
The 2.2L Turbo III, 3.3L and 3.8L engines use re-
sistor spark plugs. They have resistance values of
6,000 to 20,000 ohms when checked with at least a
1000 volt tester. 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 indi-
cates that a problem exists in the corresponding
cylinder. Replace spark plugs at the intervals recom-
mended in Group O. Spark plugs that have low milage may be cleaned
and reused if not otherwise defective. Refer to the
Spark Plug Condition section of this group. After
cleaning, file the center electrode flat with a small
point file or jewelers file. Adjust the gap between the
electrodes (Fig. 8) to the dimensions specified in the
chart at the end of this section.
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion and change
spark plug gap. Tighten 2.2L Turbo III, 3.3L and
3.8L spark plugs to 28 N Im (20 ft. lbs.) torque.
SPARK PLUG CONDITION
NORMAL OPERATING CONDITIONS
The few deposits present will be probably light tan
or slightly gray in color with most grades of commer-
cial gasoline (Fig. 9). There will not be evidence of
electrode burning. Gap growth will not average more
than approximately 0.025 mm (.001 in) per 1600 km
(1000 miles) of operation. Spark plugs that have nor-
Fig. 6 Spark Plug Wire RoutingÐ3.3L and 3.8L Engines
Fig. 7 Powertrain Control Module (PCM)
Fig. 8 Setting Spark Plug Electrode GapÐTypical
8D - 26 IGNITION SYSTEMS Ä

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