flat tire CHEVROLET DYNASTY 1993 Service Manual

should be above ADD mark. Add fluid only if level is
below ADD mark on dipstick when transaxle is
warm.The automatic transaxle does not require periodic
maintenance when used for general transportation. If
the vehicle is subjected to severe service conditions,
the automatic transaxle will require fluid/filter
change and band adjustments every 24 000 km
(15,000 miles). For additional information, refer to
Severe Service paragraph and Lubrication and Main-
tenance Schedules in General Information section of
this group. The fluid and filter should be changed
when water contamination is suspected. If fluid has
foamy or milky appearance, it is probably contami-
nated. If the fluid appears brown or dark and a foul
odor is apparent, the fluid is burned, transaxle re-
quires maintenance or service. A circular magnet lo-
cated in the transaxle pan, collects metallic particles
circulating in the oil. For proper diagnostic and ser-
vice procedures, refer to Group 21, Automatic Tran-
saxle.
SELECTING AUTOMATIC TRANSAXLE FLUID
Chrysler Corporation recommends Mopar ATF Plus
(automatic transmission fluid type 7176) be used to
add to or replace automatic transaxle fluid. If ATF
Plus is not available use Mopar Dexron II tAuto-
matic Transmission Fluid or equivalent.
DRIVE SHAFT CV AND TRIPOD JOINT BOOTS
The front drive shaft constant velocity and tripod
joint boots (Fig. 5) should be inspected when other
under vehicle service is performed. Inspect boots for
cracking, tears, leaks or other defects. If service re-
pair is required, refer to Group 2, Suspension.
FRONT WHEEL BEARINGS
The front wheel bearings are permanently sealed,
requiring no lubrication. For proper diagnostic and
service procedures refer to Group 2, Suspension.
TIRES
The tires should be inspected at every engine oil
change for proper inflation and condition. The tires
should be rotated at the distance intervals described
in the Lubrication and Maintenance Schedules of the
General Information section in this group. For tire
inflation specifications refer to the Owner's Manual.
A Tire Inflation sticker is located in the driver door
opening. For proper diagnostic procedures, see Group
22, Wheels and Tires.Fig. 2 3-speed Automatic Transaxle Fill hole
Fig. 3 4-speed Automatic Transaxle Fill tube
Fig. 4 Automatic Transaxle DipstickÐTypical
Fig. 5 Drive Shaft Boots
Ä LUBRICATION AND MAINTENANCE 0 - 17

FRONT SUSPENSION SERVICE PROCEDURES INDEX
page page
Ball Joints .............................. 13
Hub and Bearing Assembly ................. 20
Knuckle (Front Suspension) ................. 16
Lower Control Arm ....................... 10
Lower Control Arm Pivot Bushings ........... 11 Shock Absorbers (Strut Damper)
............. 10
Strut Damper Assembly ..................... 7
Suspension Coil Springs .................... 9
Sway Bar .............................. 14
Wheel Alignment .......................... 5
WHEEL ALIGNMENT
Front wheel alignment is the proper adjustment of
all interrelated front suspension angles. These angles
are what affects the running and steering of the
front wheels of the vehicle. The method of checking front alignment will vary
depending on the type of equipment being used. The
instructions furnished by the manufacturer of the
equipment should always be followed. With the ex-
ception that the alignment specifications recom-
mended by Chrysler Corporation be used. There are six basic factors which are the founda-
tion to front wheel alignment. These are height,
caster, camber, toe-in, steering axis inclination and
toe-out on turns. Of the six basic factors only camber
and toe in are mechanically adjustable (Fig. 1)
CAUTION: Do not attempt to modify any suspen-
sion or steering components by heating or bending
of the component.
Wheel alignment adjustments and checks should be
made in the following sequence. (1) Camber
(2) Toe
Camber is the number of degrees the top of the
wheel is tilted inward or outward from true vertical.
Inward tilt is negative camber. Outward tilt is posi-
tive camber. Excessive camber is a tire wear factor: negative
camber causes wear on the inside of the tire, while
positive camber causes wear to the outside. Toe
is measured in degrees or inches and is the
distance the front edges of the tires are closer (or far-
ther apart) than the rear edges. See Front Wheel
Drive Specifications for Toesettings.
PRE-ALIGNMENT
Before any attempt is made to change or correct
the wheel alignment factors. The following inspection
and necessary corrections must be made on those
parts which influence the steering of the vehicle. (1) Check and inflate tires to recommended pres-
sure. All tires should be the same size and in good
condition and have approximately the same wear.
Note type of tread wear which will aid in diagnosing,
see Wheels and Tires, Group 22. (2) Check front wheel and tire assembly for radial
runout. (3) Inspect lower ball joints and all steering link-
age for looseness. (4) Check for broken or sagged front and rear
springs. Front suspension must only be checked after the
vehicle has had the following checked or adjusted.
Tires set to recommended pressures, full tank of fuel,
no passenger or luggage compartment load and is on
a level floor or alignment rack. Just prior to each alignment reading. The vehicle
should be bounced (rear first, then front) by grasping
bumper at center and jouncing each end an equal
number of times. Always release bumpers at bottom
of down cycle.
Ä SUSPENSION AND DRIVESHAFTS 2 - 5

(3) Check solenoid to volume canister joint.
² Front strut to solenoid valve connection.
² Rear spring to solenoid valve connection.
(4) Check air line for ruptures, cuts, splits or heat
damage. Use a soap and water solution or a liquid de-
veloped for leak detection.
SYSTEM OPERATION
ENGINE RUN OPERATION
The system will compensate for load
addition/removal when.
² The trunk and all doors are closed.
² The engine speed exceeds 600 R.P.M.
² Throttle angle is less than 65 degrees.
² The brake is not applied.
² You are not cornering above 10 mph.
² There is not a charging system problem with the
vehicle.
ENGINE OFF OPERATION
After passengers/load is removed from the vehicle
the system will correct the vehicle attitude after:
² The trunk and all doors are closed.
² The ignition switch is in the OFF position.
Opening the a door or trunk wakes up the body
computer and the air suspension module. The air
suspension system is now capable of leveling, if
required.
LONG TERM IGNITION OFF OPERATION
The system is capable of one an additional leveling
cycle. After 2 continuous hours of ignition key off and
no door open or trunk open activities. This feature is
implemented to eliminate possible ice freeze-up be-
tween the tire and the inner fender shield.
SYSTEM OPERATION INHIBITORS
The air suspension system is inhibited when:
² The trunk is open.
² A door(s) is/are open.
² The brake pedal is engaged.
² The throttle is at the wide open position.
² The charging system fails.
The maximum compressor pump or exhaust
time is 3 minutes.
SYSTEM FAILURES
Vehicles equipped with air suspension and overhead
console. Will alert the driver of an air suspension
system malfunction. A warning Check Air Suspension
will appear on the overhead console screen.
SAFETY CONCERNS
WARNING: REAR AIR SPRINGS MUST BE DEFLATED
BEFORE BEING REMOVED FROM THE VEHICLE.
WARNING: OPEN TRUNK, OR DOOR(S) OR REMOVE
GROUND STRAP FROM BATTERY BEFORE HOIST-
ING OR JACKING A VEHICLE DURING MECHANICAL
REPAIRS.
WARNING: IF THE VEHICLE NEEDS SERVICE OR
REPAIR OF THE REAR SHOCK ABSORBERS OR
REAR AXLE PIVOT BUSHINGS. THE REAR AIR
SPRINGS MUST HAVE THE AIR PRESSURE RE-
MOVED BEFORE THE VEHICLE CAN BE SERVICED
SAFELY.
SHIPPING MODE
(1) Removing shipping height signal for customer
use.
² Use DRB II tester and 1991 Chassis (Air Suspen-
sion) service cartridge.
² Follow DRB II requirements to cancel shipping
height message in the body computer.
² Connect the Ignition Off Draw (I.O.D.) circuit.
The connection of the IOD circuit will cancel
the Shipping height signal. (2) Return to shipping height.
² Set shipping command in the body computer using
the DRB II and the 1991 Chassis (Air suspension)
service cartridge.
² Disconnect the I.O.D. connector.
DIAGNOSIS
INITIAL DIAGNOSTIC CHECK
(1) Check for blown or missing fuses.
Fig. 9 Compressor Current Draw Test
2 - 78 SUSPENSION AND DRIVESHAFTS Ä

INSTALL
(1) Inspect O-Ring condition and position on sole-
noid stem. (O-Ring can become dislodged during re-
moval (Fig. 16). (2) Install solenoid with tangs to top ledge of hous-
ing and install retaining clip. (3) Reconnect air line and electrical connection.
STRUT (AIR SUSPENSION) DAMPERASSEMBLY
Service procedures for removal and installation for
(air or steel spring) assemblies are essentially the
same. Except for air venting/recharging and discon-
necting/connecting air lines and electrical connection.
REMOVAL (1) Disconnect battery negative cable.
(2) Hoist vehicle and remove wheel and tire assem-
bly. (3) See AIR LINES AND FITTINGS and discon-
nect air line. (4) Disconnect electrical leads, solenoid and height
sensors. (5) See SOLENOIDS (STRUT AND AIR SPRING)
and vent air spring and remove solenoids. (6) See STRUT DAMPER ASSEMBLY in FRONT
SUSPENSION and remove strut.
DISASSEMBLY/ASSEMBLE Disassembly is restricted to upper mount and bear-
ing housing. The strut shock absorber, air spring
with integral height sensor, solenoid and wiring har-
ness are serviced as an assembly. (1) Hold retaining plate locking washer and re-
move strut rod nut. (2) Remove locking washer, retainer plate, spacer,
flat washer and mount/bearing housing assembly
(Fig. 17). (3) Assemble in reverse order. Hold retainer plate
locking washer with suitable tool and tighten strut
rod nut to 75 N Im (55 ft. lbs.) torque.
INSTALLATION (1) See STRUT DAMPER ASSEMBLY in FRONT
SUSPENSION and install strut. (2) Install solenoid, see: SOLENOIDS (STRUT
AND AIR SPRINGS). (3) Connect electrical leads, solenoid and height
sensor. (4) Charge (inflate) air spring. See RECHARGE-
AIR SPRING to activate spring solenoid and air com-
pressor. Add air for 60 seconds.
RECHARGE AIR SPRING
To activate compressor; Ground Pin S08 to Pin
X20. To Activate Spring Solenoid:
² LF: Ground Pin S31 to X20 ²
RF: Ground Pin S30 to X20
² RR: Ground Pin S32 to X20
AIR SPRINGS REAR
REMOVAL
(1) Disconnect battery negative cable, hoist vehicle
and remove wheel and tire assembly. (2) See AIR LINES AND FITTINGS and discon-
nect air line and electrical connector from solenoid. (3) See SOLENOIDS (STRUT AND AIR SPRINGS)
and vent air from spring. Remove solenoid. (4) Release upper air spring alignment/retainer
clips. (Fig. 18) (5) Remove lower spring to axle nut (Fig. 19).
(6) Pry assembly down to pull alignment studs
through retaining clips (Fig. 20). Remove assembly.
INSTALLATION
(1) Position assembly lower stud into axle seat and
upper alignment pins through frame rail adaptor. (2) Install upper retaining clips.
(3) Install lower spring to axle nut: LOOSE AS-
SEMBLE. (4) Install solenoid and connect air line and electri-
cal connector. (5) Charge (inflate) air spring. See RECHARGING
AIR SPRING and add air for 60 seconds. (6) AFTER partial air recharge tighten lower nut
Fig. 17 Air Strut Upper Mount Assembly
Ä SUSPENSION AND DRIVESHAFTS 2 - 87

cylinder bore and piston for scoring and pitting. (Do
not use a rag as lint from the rag will stick to bore
surfaces.) Wheel cylinder bores and pistons that are scored or
pitted in any way should be replaced. Cylinder walls
that have light scratches, or show signs of corrosion,
can usually be cleaned with crocus cloth, using a cir-
cular motion. Black stains on the cylinder walls are
caused by piston cups and will not impair operation
of cylinder.
ASSEMBLING WHEEL CYLINDERS
Before assembling the pistons and new cups in the
wheel cylinders, dip them in clean brake fluid. If the
boots are deteriorated, cracked or do not fit tightly
on the pistons or the cylinder casting, install new
boots. (1) Coat cylinder bore with clean brake fluid.
(2) Install expansion spring with cup expanders in
cylinder. Install cups in each end of cylinder with
open end of cups facing each other (Fig. 3). (3) Install piston in each end of cylinder having
the flat face of each piston contacting the flat face of
each cup, already installed (Fig. 3). (4) Install a boot over each end of cylinder. Be
careful not to damage boot during installation.
INSTALLING WHEEL CYLINDERS
(1) Apply Mopar tGasket In-A-Tube or equivalent
sealant around wheel cylinder mounting surface (Fig.
4). (2) Install wheel cylinder onto brake support, and
tighten the wheel cylinder to brake support plate at-
taching bolts to 8 N Im (75 in. lbs.). (3) Attach hydraulic brake tube to wheel cylinder,
and tighten tube to wheel cylinder fitting to 17 N Im
(145 in. lbs.). (4) Install brake shoes on support plate.
(5) Install rear brake drum onto rear hub. Install
rear wheel and tire assembly, tighten wheel stud
nuts to 115 N Im (85 ft. lbs.).
(6) Adjust the rear brakes, (See Adjusting Service
Brakes) in Service Adjustments section in this group
of the service manual. (7) Bleed the entire brake system. See (Bleeding
Brake System) in Service Adjustments section in this
group of the service manual.
Fig. 3 Rear Wheel Cylinder
Fig. 4 Apply Sealant on Support Plate
5 - 24 BRAKES Ä

seal, a new seal should be used when reinstalling the
inner bearing. (See Fig. 1) (5) Thoroughly clean all old grease from the outer
and inner bearings, bearing cups and hub cavity (See
Fig. 1). To clean bearings, soak them in an ap-
propriate cleaning solvent. Strike the flat sur-
face of the bearing inner race against a
hardwood block several times. Immerse the
bearings in solvent between the blows to jar
grease loose and wash old particles of hardened
grease from bearings. Repeat this operation un-
til bearings are clean. Bearings can be dried
using compressed air but do not spin the bear-
ings. After cleaning, oil the bearings with engine
oil. Insert the bearing into its appropriate cup,
apply pressure to the bearing while rotating it to
test them for pitting and roughness. Replace all
worn or defective bearings. If bearing shows signs of pitting or roughness they should be
replaced. Bearings must be replaced as a set,
both the cup and the bearing need to be replaced
at the same time. If bearings are suitable for
further use, remove engine oil from bearings
using appropriate solvent and dry bearings. Re-
pack the bearings using a Multi-Purpose NLGI.
Grade 2 EP Grease such as Mopar or equivalent,
and place them in a clean covered container
until ready for installation. If a bearing packer is
not available, hand pack grease into all cavities
between bearing cage and rollers. (6) If bearings and cups are to be replaced, remove
cups from the drum or hub using a brass drift or
suitable remover. (7) Replace bearing cups with appropriate installing
tool. (8) Install inner bearing in grease coated hub and
bearing cup, and install new grease seals using the
appropriate seal installer. (9) Coat hub cavity and cup with grease.
(10) Before installing hub or drum assembly, inspect
stub axle and seal surface for burrs or roughness, and
smooth out all rough surfaces. (11) Coat the stub axle with Multi-Purpose NLGI,
Grade 2 EP grease such as Mopar or equivalent. (12) Carefully slide the hub of drum assembly onto
the stub axle. Do not drag seal or inner bearing
over the threaded area of the stub axle. (13) Install outer bearing, thrust washer and nut.
(14) Tighten the wheel bearing adjusting nut to 27 to
34 N Im (240 to 300 in. lbs.) while rotating hub or drum
assembly. This seats the bearings. (15) Back off adjusting nut 1/4 turn (90É) then
tighten adjusting nut only finger tight. (16) Position the nut lock over the bearing adjusting
nut with one pair of slots in line with the cotter pin hole
in the stub axle, and install cotter pin. (17) Install the grease caps and the wheel and tire
assemblies. Tighten wheel stud nuts to 115 N Im (85 ft.
lbs.) on all models. reinstall wheel covers if so
equipped.
Fig. 1 Rear Wheel Bearings
Ä BRAKES 5 - 71

stant velocity joint housings. The rear Tone Wheels
are serviced as an assembly with the rear disc brake
rotor hub. Correct Anti-Lock System operation is dependent
on wheel speed signals from the wheel speed sensors.
The vehicles' wheels and tires must all be the same
size and type to generate accurate signals. In addi-
tion, the tires must be inflated to the recommended
pressures for optimum system operation. Variations
in wheel and tire size or significant variations in in-
flation pressure can produce inaccurate wheel speed
signals.
CONTROLLER ANTI-LOCK BRAKE (CAB)
The Anti-Lock Brake Controller is a small micro-
processor based device that monitors the brake sys- tem and controls the system while it functions in
Anti-Lock Mode. The CAB is located under the bat-
tery tray and is mounted to the left frame rail (Fig.
7) and uses a 60-way system connector. The power
source for the CAB is through the ignition switch to
pin 60 of the controller. With the ignition in the
RUN or ON position. IF THE (ABS) CONTROL-
LER NEEDS TO BE REPLACED BE SURE THE
CORRECT CONTROLLER IS USED. THE CON-
TROLLER ANTI-LOCK BRAKE (CAB) IS NOT
ON THE CCD BUS
Fig. 5 Rear Wheel Speed Sensor
Fig. 4 Front Wheel Speed Sensor
Fig. 6 Rear Tone Wheel
Fig. 7 Location Controller Anti-Lock Brake (CAB)
5 - 80 ANTI-LOCK 10 BRAKE SYSTEM Ä

PROPORTIONING VALVES
Two Proportioning Valves (Fig. 3) are used in the
system, one for each rear brake hydraulic circuit.
The Proportioning Valves function the same as in a
standard brake system. The Proportioning Valves are
located on the bottom of the hydraulic assembly (Fig.
1). They are the same screw in type as the ones used
on the Bendix Anti-Lock 10 and Bosh Anti-Lock
Brake systems.
WHEEL SPEED SENSORS
One Wheel Speed Sensor (WSS), is located at each
wheel (Fig. 4 and 5), and sends a small (AC) signal
to the control module (CAB). This signal is generated
by magnetic induction. The magnetic induction is
created, when a toothed sensor ring Tone Wheel (Fig.
6) passes a stationary magnetic Wheel Speed Sensor.
The (CAB) converts the (AC) signal generated at
each wheel into a digital signal. If a wheel locking
tendency is detected, the (CAB) will then modulate
hydraulic pressure to prevent the wheel(s) from lock-
ing. The front Wheel Speed Sensor is attached to a boss
in the steering knuckle (Fig. 4). The tone wheel is
part of the outboard constant velocity joint. The rear
Wheel Speed Sensor is mounted to the caliper adap-
tor (Fig. 5) and the rear tone wheel is an integral
part of the rear wheel hub (Fig. 6). The speed sensor
air gap is NOT adjustable. The four Wheel Speed Sensors are serviced individ-
ually. The front Tone Wheels are serviced as an as-
sembly with the outboard constant velocity joint. The
rear Tone Wheels are serviced as an assembly with
the rear brake hub. Correct Anti-Lock system operation is dependent
on the vehicle's wheel speed signals, that are gener-
ated by the Wheel Speed Sensors. The vehicle's
wheels and tires must all be the same size and type
to generate accurate signals. In addition, the tires
must be inflated to the recommended pressures for
optimum system operation. Variations in wheel and
tire size or significant variations in inflation pres-
sure can produce inaccurate wheel speed signals.
Fig. 3 Proportioning Valve Identification
Fig. 4 Front Wheel Speed Sensor
Fig. 5 Rear Wheel Speed Sensor
5 - 118 ANTI-LOCK 6 BRAKE SYSTEM Ä

WHEEL SPEED SENSORS
One Wheel Speed Sensor (WSS), is located at each
wheel (Fig. 5 and 6), and sends a small AC signal to the
control module CAB. This signal is generated by mag-
netic induction. The magnetic induction is created,
when a toothed sensor ring (Tone Wheel) (Fig. 7) passes
a stationary magnetic Wheel Speed Sensor. The CAB
converts the AC signal generated at each wheel into a
digital signal. If a wheel locking tendency is detected,
the CAB will then modulate hydraulic pressure to pre-
vent the wheel or wheels from locking.
The front Wheel Speed Sensor is attached to a boss
in the steering knuckle (Fig. 5). The tone wheel is
part of the outboard constant velocity joint (Fig. 5). The rear Wheel Speed Sensor is mounted to the cal-
iper adapter (Fig. 6) and the rear tone wheel is an
integral part of the rear wheel hub (Fig. 7). The
speed sensor air gap is NOT adjustable.
The four Wheel Speed Sensors are serviced individ-
ually. The front Tone Wheels are serviced as an as-
sembly with the outboard constant velocity joint. The
rear Tone Wheels are serviced as an assembly with
the rear brake hub. Correct Antilock system operation is dependent on
the vehicle's wheel speed signals, that are generated
by the Wheel Speed Sensors. The vehicle's wheels
and tires must all be the same size and type to gen-
erate accurate signals. In addition, the tires must be
inflated to the recommended pressures for optimum
system operation. Variations in wheel and tire size
or significant variations in inflation pressure can
produce inaccurate wheel speed signals.
CONTROLLER ANTILOCK BRAKE CAB
The Antilock Brake Controller is a small micropro-
cessor based device which monitors the brake system
and controls the system while it functions in the An-
tilock mode. The CAB is mounted on the top of the
right front frame rail and uses a 60-way system con-
nector (Fig. 8). The power source for the CAB is
through the ignition switch in the Run or On posi-
tion. THE CONTROLLER ANTILOCK BRAKE
CAB IS NOT ON THE CCD BUS The primary functions of the CAB are:
(1) Detect wheel locking tendencies.
(2) Control fluid modulation to the brakes while in
Antilock mode. (3) Monitor the system for proper operation.
Fig. 5 Front Wheel Speed Sensor
Fig. 6 Rear Wheel Speed Sensor
Fig. 7 Rear Tone Wheel (Typical)
5 - 18 ANTILOCK 4 BRAKE SYSTEM 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