spark plugs replace CHEVROLET DYNASTY 1993 Service Manual

ENGINE INDEX
page page
Engine Oil Filter .......................... 9
Battery ................................ 15
Crankcase Ventilation System ............... 13
Drive Belts ............................. 14
Emission Control System ................... 14
Engine Air Cleaner ....................... 11
Engine Cooling System .................... 10 Engine Oil
............................... 8
Frequency of Engine Oil and Filter Changes ..... 8
Fuel Filter .............................. 14
Fuel Recommendations .................... 14
Ignition Cables, Distributor Cap, and Rotor ..... 14
Rubber and Plastic Component Inspection ...... 15
Spark Plugs ............................ 14
FREQUENCY OF ENGINE OIL AND FILTER
CHANGES
ENGINE OIL
Road conditions as well as your kind of driving af-
fect the interval at which your oil should be changed.
Check the following to determine if any apply to you:
² Frequent short trip driving less than 8 kilometers
(5 miles)
² Frequent driving in dusty conditions
² Frequent trailer towing
² Extensive idling (such as vehicle operation in stop
and go traffic)
² More than 50% of your driving is at sustained
high speeds during hot weather, above 32ÉC (90ÉF) If any of these apply to you then change your en-
gine oil every 4 800 kilometers (3,000 miles) or 3
months, whichever comes first. If none of these apply to you then change your oil
every 12 000 kilometers (7,500 miles) or 6 months,
whichever comes first. If none of these apply and the vehicle is in com-
mercial type service such as, Police, Taxi or Limou-
sine and principally used for highway driving of 40
kilometers (25 miles) or more between stations, the
engine oil should be changed every 8 000 kilometers
(5,000 miles) or 6 months, whichever comes first.
FLEXIBLE FUEL VEHICLES
Flexible fuel is corrosive and contributes to engine
oil contamination. When flexible fuel is being used,
the engine oil should be changed every 8 000 kilome-
ters (5,000 miles) or 6 months, whichever comes first.
OIL FILTER
The engine oil filter should be replaced with a new
filter at every second oil change.
ENGINE OIL
WARNING: NEW OR USED ENGINE OIL CAN BE IR-
RITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED
BY INTERNAL COMBUSTION, CAN BE HAZARDOUS TO YOUR HEALTH. THOROUGHLY WASH EX-
POSED SKIN WITH SOAP AND WATER. DO NOT WASH SKIN WITH GASOLINE, DIESEL
FUEL, THINNER, OR SOLVENTS, HEALTH PROB-
LEMS CAN RESULT. DO NOT POLLUTE, DISPOSE OF USED ENGINE
OIL PROPERLY. CONTACT YOUR DEALER OR
GOVERNMENT AGENCY FOR LOCATION OF COL-
LECTION CENTER IN YOUR AREA.
BREAK-IN PERIOD
CAUTION: Wide open throttle operation in low
gears, before engine break-in period is complete,
can damage engine.
On a Chrysler Corporation vehicle an extended
break-in period is not required. Driving speeds of not
over 80-90 km/h (50-55 mph) for the first 100 km (60
miles) is recommended. Hard acceleration and high
engine rpm in lower gears should be avoided.
SELECTING ENGINE OIL
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase lu-
bricant. Engine or Turbocharger failure can result.
The factory fill engine oil is a high quality, energy
conserving, crankcase lubricant. The Recommended
SAE Viscosity Grades chart defines the viscosity
grades that must be used based on temperature in
the region where vehicle is operated and optional
equipment.
NON-FLEXIBLE FUEL VEHICLES Chrysler Corporation recommends that Mopar mo-
tor oil, or equivalent, be used when adding or chang-
ing crankcase lubricant. The API symbol (Fig. 1) on
the container indicates the viscosity grade, quality
and fuel economy ratings of the lubricant it contains.
Use ENERGY CONSERVING II motor oil with API
SERVICE SG or SG/CD classification.
0 - 8 LUBRICATION AND MAINTENANCE Ä

PCV SYSTEM TEST
Refer to group 25, Emission Control System for
proper procedures to test PCV system.
FUEL RECOMMENDATIONS
Chrysler Corporation recommends that only fuel pur-
chased from a reputable retailer be used. Use high qual-
ity, unleaded gasoline to provide satisfactory
driveability and highest fuel economy. Gasoline contain-
ing detergent and corrosion control additives are desire-
able. If the engine develops spark knock (audible ping),
poor performance, hard starting or stalling, purchase
fuel from another source. Engine performance can vary
when using different brands of gasoline with the same
octane rating. Occasional light engine spark knock un-
der heavy acceleration, at low speed or when vehicle is
heavily loaded is not harmful. Extended periods of
spark knock under moderate acceleration or at cruising
speed can damage the engine. The cause of excessive
spark knock condition must be diagnosed and corrected.
For diagnostic procedures refer to Group 14, Fuel Sys-
tem and Powertrain Diagnostic Procedures manual.
SELECTING GASOLINE
CAUTION:Do not use fuel containing METHANOL
(methyl or wood alcohol), damage to fuel system
will result. Do not use leaded gasoline, damage to catalytic
converter will result and vehicle will not conform to
emission control standards.
ETHANOL, MTBE OR ETBE BLENDS
All Chrysler Corporation vehicles are designed to
use unleaded gasoline ONLY. Gasohol blends, con-
taining 10% Ethanol (ethyl or grain alcohol) 90% un-
leaded gasoline can be used provided it has adequate
octane rating. Fuel blends containing up to 15% MTBE (Methyl
Tertiary Butyl Ether) and 85% unleaded gasoline can
be used. Fuel blends containing up to 17% ETBE
(Ethyl Tertiary Butyl Ether) and 83% unleaded gas-
oline can also be used. Fuel blended with ethanol, MTBE or ETBE are
also referred to as reformulated or clean air gasoline.
These fuels contribute less emissions to the atmo-
sphere. Chrysler Corporation recommends that
blended fuels be used when available
METHANOL BLENDS Using gasoline blended with methanol can result
in starting and driveability problems. Deterioration
of fuel system components will result. Methanol in-
duced problems are not the responsibility of Chrysler
Corporation and may not be covered by the vehicle
warranty. NON-TURBOCHARGED ENGINES
Use regular unleaded gasoline having a minimum
octane rating of 87 (R+M)/2. Higher octane premium
unleaded gasoline can be used if desired.
2.2L 16 VALVE TURBOCHARGED ENGINE
Use premium unleaded gasoline having a mini-
mum octane rating of 91 (R+M)/2. Gasoline with oc-
tane rating less than 91 (R+M)/2 can be used if
recommended gasoline is not available. Low octane
gasoline will reduce engine performance.
FLEXIBLE FUEL VEHICLES
CAUTION: Do not use 100% methanol, damage to
fuel system can result. Use unleaded regular gasoline having a minimum
octane rating of 87 (R=M)/2 and M85 fuel that is
85% methanol and 15% unleaded gasoline, or a mix-
ture of these two.
FUEL FILTER
The fuel filter requires service only when a fuel
contamination problem is suspected. For proper diag-
nostic and service procedures refer to Group 14, Fuel
System,
IGNITION CABLES, DISTRIBUTOR CAP, AND
ROTOR
Inspect and test ignition cables, distributor cap and
rotor when the spark plugs are replaced. Oil and
grime should be cleaned from the ignition cables and
distributor cap to avoid possible spark plug fouling.
Mopar, Foamy Engine Degreaser, or equivalent is
recommended for cleaning the engine compartment.
For proper service and diagnostic procedures refer to
Group 8D, Ignition System.
SPARK PLUGS
Ignition spark plugs should be replaced at the
mileage interval described in the Lubrication and
Maintenance Schedules. Refer to the General Infor-
mation section of this group. For proper service pro-
cedures refer to Group 8D, Ignition Systems.
DRIVE BELTS
Inspect and adjust drive belts at the interval de-
scribed in the Lubrication and Maintenance Sched-
ules. Refer to General Information section of this
group. For proper inspection and adjustment proce-
dures, see Group 7, Cooling System.
EMISSION CONTROL SYSTEM
Inspect all emission control components and hoses
when other under hood service is performed. Refer to
emission system Vacuum Hose Label located on the
0 - 14 LUBRICATION AND MAINTENANCE Ä

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

Light scaling of the terminals can be cleaned with
a sharp knife. If the terminals are heavily scaled, re-
place the distributor cap. A cap that is greasy, dirty or has a powder-like
substance on the inside should be cleaned with a so-
lution of warm water and a mild detergent. Scrub
the cap with a soft brush. Thoroughly rinse the cap
and dry it with a clean soft cloth.
ROTOR
Replace the rotor if it is cracked, the tip is exces-
sively burned or heavily scaled (Fig. 4). If the spring
terminal does not have adequate tension, replace the
rotor.
SPARK PLUG CABLES
Spark Plug cables are sometimes referred to as sec-
ondary ignition wires. They transfer electrical cur-
rent from the distributor to individual spark plugs at
each cylinder. 2.2L TBI, 2.5L TBI, 2.5L MPI, Turbo
III and 3.0L engines use resistance type cables. The
cables suppress radio frequency 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 connec-
tions can cause ignition malfunctions by permitting
water to enter the towers, corroding, and increasing
resistance. To maintain proper sealing at the ter-
minal connections, the connections should not
be broken unless testing indicates high resis-
tance, an open circuit or other damage.
CAUTION: Do not pull spark plug cables from dis-
tributor cap of four cylinder engines. The cables must
be released from inside the distributor cap (Fig. 5).
Clean high tension cables with a cloth moistened
with a non-flammable solvent and wipe dry. Check for
brittle or cracked insulation.
Fig. 2 Engine Firing OrderÐ2.2L TBI, 2.5L TBI, 2.5L MPI and Turbo III Engines
Fig. 3 Engine Firing OrderÐ3.0L Engine
Fig. 4 Rotor InspectionÐTypical
Fig. 5 Spark Plug Cable Removal/InstallationÐ2.2L and 2.5L TBI Engines
8D - 2 IGNITION SYSTEMS Ä

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

(Fig. 9). This short circuits the electrodes. Spark
plugs with electrode gap bridging can be cleaned us-
ing standard procedures.
SCAVENGER DEPOSITS Fuel scavenger deposits may be either white or yel-
low (Fig. 10). They may appear to be harmful, but
are a normal condition caused by chemical additives
in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Accumulation on the
ground electrode and shell area may be heavy but
the deposits are easily removed. Spark plugs with
scavenger deposits can be considered normal in con-
dition and be cleaned using standard procedures.
CHIPPED ELECTRODE INSULATOR A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation also can separate the insulator
from the center electrode (Fig. 11). Replace spark
plugs with chipped electrode insulators. PREIGNITION DAMAGE
Excessive combustion chamber temperature can
cause preignition damage. The center electrode dis-
solves first and the ground electrode dissolves some-
what later (Fig. 12). Insulators appear relatively
deposit free. Determine if the spark plug has the cor-
rect heat range rating for the engine, if ignition tim-
ing is over advanced or if other operating conditions
are causing engine overheating. The heat range rat-
ing refers to the operating temperature of a particu-
lar type spark plug. Spark plugs are designed to
operate within specific temperature ranges depend-
ing upon the thickness and length of the center elec-
trode and porcelain insulator.
SPARK PLUG OVERHEATING Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
13). The increase in electrode gap will be consider-
ably in excess of 0.001 in per 1000 miles of operation.
This suggests that a plug with a cooler heat range
rating should be used. Over advanced ignition tim-
Fig. 9 Electrode Gap Bridging
Fig. 10 Scavenger Deposits
Fig. 11 Chipped Electrode Insulator
Fig. 12 Preignition Damage
Ä IGNITION SYSTEMS 8D - 5

2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNITION SYSTEMSÐDIAGNOSTIC PROCEDURES
INDEX
page page
Coolant Temperature Sensor Test ............ 13
Failure to Start TestÐ2.5L TBI and 3.0L Engines . 12
General Information ....................... 11
Ignition Coil ............................. 11 Manifold Absolute Pressure (MAP) Sensor Test . 13
Poor Performance Test .................... 13
Spark Plugs ............................ 11
Testing for Spark at Coil ................... 11
GENERAL INFORMATION
For additional information, refer to On Board Di-
agnostics in the Fuel Injection General Diagnosis
sections of Group 14. Also, refer to the DRBII scan
tool and appropriate Powertrain Diagnostic Proce-
dures Manual.
SPARK PLUGS
Faulty or fouled spark plugs may perform well at
idle speed, but frequently fail at higher engine
speeds. Faulty plugs can be identified in a number of
ways: poor fuel economy, power loss, decrease in en-
gine speed, hard starting and, in general, poor en-
gine performance. Spark plugs also malfunction because of carbon
fouling, excessive electrode air gap, or a broken insu-
lator. Refer to the General Information Section of
this group for spark plug diagnosis.
IGNITION COIL
The ignition coil is designed to operate without an
external ballast resistor. Inspect the coil for arcing. Test the coil according
to coil tester manufacturer's instructions. Test coil
primary and secondary resistance. Replace any coil
that does not meet specifications. Refer to the Coil
Resistance chart. If the ignition coil is replaced due to a burned
tower, carbon tracking, arcing at the tower, or dam-
age to the terminal or boot on the coil end of the sec-
ondary cable, the cable must be replaced. Arcing at the tower will carbonize the nipple which, if it is con-
nected to a new coil, will cause the coil to fail. If a secondary cable shows any signs of damage,
the cable should be replaced with a new cable and
new terminal. Carbon tracking on the old cable can
cause arcing and the failure of a new coil.
TESTING FOR SPARK AT COIL
WARNING: APPLY PARKING BRAKE AND/OR
BLOCK THE WHEELS BEFORE PERFORMING ANY
TEST WITH THE ENGINE RUNNING.
CAUTION: Spark plug cables may be damaged if
this test is performed with more than 1/4 inch clear-
ance between the cable and engine ground.
Remove the coil secondary cable from the distribu-
tor cap. Hold the end of cable about 6 mm (1/4-inch)
away from a good engine ground (Fig. 1). Crank the
engine and inspect for spark at the coil secondary ca-
ble. There must be a constant spark at the coil second-
ary cable. If the spark is constant, have a helper con-
tinue to crank engine and, while slowly moving coil
secondary cable away from ground, look for arcing at
the coil tower. If arcing occurs at the tower, replace
the coil. If spark is not constant or there is no spark,
proceed to the failure to start test. If a constant spark is present and no arcing occurs
at the coil tower, the ignition system is producing
the necessary high secondary voltage. However,
COIL RESISTANCE
Ä IGNITION SYSTEMS 8D - 11

make sure that the spark plugs are firing. Inspect the
distributor rotor, cap, spark plug cables, and spark
plugs. If they are in proper working order, the ignition
system is not the reason why the engine will not start.
Inspect the fuel system and engine for proper opera-
tion.
FAILURE TO START TESTÐ2.5L TBI AND 3.0L
ENGINES
Before proceeding with this test make sure
Testing For Spark At Coil has been performed.
Failure to do this may lead to unnecessary diag-
nostic time and wrong test results.
WARNING: BE SURE TO APPLY PARKING BRAKE
AND/OR BLOCK WHEELS BEFORE PERFORMING
ANY TEST WITH THE ENGINE RUNNING.
(1) Battery voltage must be at least 12.4 volts to
perform test. (2) Crank the engine for 5 seconds while monitoring
the voltage at the coil positive (+) terminal (Fig. 2 or
Fig. 3). If the voltage remains near zero during the
entire period of cranking, refer to Group 14 for On-
Board Diagnostic checks. Also, refer to the DRBII scan
tool and the appropriate Powertrain Diagnostic Proce-
dures manual. These checks will help diagnose prob-
lems with the PCM and auto shutdown relay. (3) If voltage is at near-battery voltage and drops to
zero after 1-2 seconds of cranking, refer to On-Board
Diagnostic in Group 14. Also, refer to the DRBII scan
tool and the appropriate Powertrain Diagnostic Proce-
dures manual. These tests will help check the distribu-
tor reference pickup circuit to the PCM. (4) If voltage remains at near battery voltage during
the entire 5 seconds, with the key off,remove the
PCM 60-way connector. Check the 60-way connector
for any terminals that are pushed out or loose. (5) Remove the connector to coil (+) and connect a
jumper wire between battery (+) and coil (+). (6) Using the special jumper (Fig. 4), momentarily ground terminal #19 of the 60-way connector (Fig.
5). A spark should be generated when the ground is
removed.
(7) If spark is generated, replace the PCM.
(8) If no spark is seen, use the special jumper to
ground the coil (-) terminal directly. (9) If spark is produced, inspect wiring harness for
an open condition.
Fig. 2 Coil TerminalsÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines
Fig. 3 Coil TerminalsÐ3.0L Engine
Fig. 4 Special Jumper to Ground Coil Negative
Fig. 1 Checking for Spark
8D - 12 IGNITION SYSTEMS Ä

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

SCAVENGER DEPOSITS Fuel scavenger deposits may be either white or yel-
low (Fig. 12). They may appear to be harmful, but
are a normal condition caused by chemical additives
in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Accumulation on the
ground electrode and shell area may be heavy but
the deposits are easily removed. Spark plugs with
scavenger deposits can be considered normal in con-
dition and be cleaned using standard procedures.
CHIPPED ELECTRODE INSULATOR A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation also can separate the insulator
from the center electrode (Fig. 13). Spark plugs with
chipped electrode insulators must be replaced.
PREIGNITION DAMAGE
Excessive combustion chamber temperature can
cause preignition damage. First, the center electrode
dissolves and the ground electrode dissolves some- what later (Fig. 14). Insulators appear relatively de-
posit free. Determine if the spark plug has the
correct heat range rating for the engine, if ignition
timing is over advanced or if other operating condi-
tions are causing engine overheating. The heat range
rating refers to the operating temperature of a par-
ticular type spark plug. Spark plugs are designed to
operate within specific temperature ranges depend-
ing upon the thickness and length of the center elec-
trode and porcelain insulator.
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
15). The increase in electrode gap will be consider-
ably in excess of 0.001 in per 1000 miles of operation.
This suggests that a plug with a cooler heat range
rating should be used. Over advanced ignition tim-
ing, detonation and cooling system malfunctions also
can cause spark plug overheating.
CAMSHAFT POSITION SENSOR
The camshaft position sensor provides fuel injection
synchronization and cylinder identification informa-
Fig. 12 Scavenger Deposits
Fig. 13 Chipped Electrode Insulator
Fig. 14 Preignition Damage
Fig. 15 Spark Plug Overheating
8D - 28 IGNITION SYSTEMS Ä