Stud loose in
taper hole ............. A ........... (7) Require repair or
replacement.
Taper hole elongated .... A ........ ( 8) Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ........ ( 7) Require replacement.
Wear exceeds
manufacturer's
specifications .......... B ............ Require replacement.
( 1) - If greaseable, grease joint. If problem persists or
joint is non-greaseable, require replacement.
( 2) - Cracked grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 3) - Lack of grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 4) - Torn grease boot will allow contaminants to enter the
joint and will accelerate wear.
( 5) - If manufacturer's procedures for inspection exist, use
those procedures; otherwise, use an approved inspection
method such as the dry park check.
CAUTION: DO NOT use pliers or pry bar to check ball and
socket movement. Use only moderate hand pressure.
( 6) - Excessive looseness is defined as being significant
enough to affect vehicle handling or structural
integrity.
( 7) - Check for damaged taper hole.
( 8) - Check for damaged stud.
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SHOCK ABSORBERS, STRUT CARTRIDGES AND STRUT ASSEMBLIES
You are not required to replace shocks or struts in axle
sets. However, when replacing a shock or strut due to the conditions
that follow, you may suggest replacement of the other shock or strut
on the same axle for improved performance and preventive maintenance.
* Part is close to the end of its useful life
* To extend tire life
* To balance ride and handling
* To improve stopping distance
When replacing steering and/or suspension components which
may affect an alignment angle, you are required to check and adjust
alignment as needed. Refer to the OEM specifications.
Under no circumstances should a technician bend struts or
strut housings.
A vehicle's load-carrying and handling abilities are limited
by its suspension, tires, brakes, and driveline. Installing coil over
shocks or any other load assist device does not increase the vehicle's
load capacity. See the vehicle owner's manual for more details.
NOTE: If vehicle is equipped with original equipment coil over
shocks, apply the conditions for coil springs from the
SPRINGS - COIL, LEAF AND TORSION BAR section of the
STEERING AND SUSPENSION guidelines. If the vehicle is
equipped with add-on coil over shocks, you may suggest
replacing the shocks with standard shocks for any spring-
related condition.
SHOCK ABSORBER, STRUT CARTRIDGE AND STRUT ASSEMBLY INSPECTION
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Stud loose in
taper hole ............. A ........... (7) Require repair or
replacement.
Taper hole elongated .... A ........ ( 8) Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ........ ( 7) Require replacement.
Wear exceeds
manufacturer's
specifications .......... B ............ Require replacement.
( 1) - If greaseable, grease joint. If problem persists or
joint is non-greaseable, require replacement.
( 2) - Cracked grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 3) - Lack of grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 4) - Torn grease boot will allow contaminants to enter the
joint and will accelerate wear.
( 5) - If manufacturer's procedures for inspection exist, use
those procedures; otherwise, use an approved inspection
method such as the dry park check.
CAUTION: DO NOT use pliers or pry bar to check ball and
socket movement. Use only moderate hand pressure.
( 6) - Excessive looseness is defined as being significant
enough to affect vehicle handling or structural
integrity.
( 7) - Check for damaged taper hole.
( 8) - Check for damaged stud.
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SHOCK ABSORBERS, STRUT CARTRIDGES AND STRUT ASSEMBLIES
You are not required to replace shocks or struts in axle
sets. However, when replacing a shock or strut due to the conditions
that follow, you may suggest replacement of the other shock or strut
on the same axle for improved performance and preventive maintenance.
* Part is close to the end of its useful life
* To extend tire life
* To balance ride and handling
* To improve stopping distance
When replacing steering and/or suspension components which
may affect an alignment angle, you are required to check and adjust
alignment as needed. Refer to the OEM specifications.
Under no circumstances should a technician bend struts or
strut housings.
A vehicle's load-carrying and handling abilities are limited
by its suspension, tires, brakes, and driveline. Installing coil over
shocks or any other load assist device does not increase the vehicle's
load capacity. See the vehicle owner's manual for more details.
NOTE: If vehicle is equipped with original equipment coil over
shocks, apply the conditions for coil springs from the
SPRINGS - COIL, LEAF AND TORSION BAR section of the
STEERING AND SUSPENSION guidelines. If the vehicle is
equipped with add-on coil over shocks, you may suggest
replacing the shocks with standard shocks for any spring-
related condition.
SHOCK ABSORBER, STRUT CARTRIDGE AND STRUT ASSEMBLY INSPECTION
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various switch input operations to adjust IAC motor to obtain optimum
idle conditions. Deceleration stall is prevented by increasing airflow
when throttle is closed suddenly.
IGNITION SYSTEM
NOTE: Pickup equipped with 8.0L engine uses Distributorless
Ignition system (DIS). All other models use a Hall Effect
ignition system.
The PCM completely controls ignition system. During
crank/start mode, PCM will set a fixed amount of spark advance for an
efficient engine start. Amount of spark advance or retard is
determined by inputs that PCM receives from ECT sensor, engine vacuum
and engine RPM. During engine operation, PCM can supply an infinite
number of advance curves to ensure proper engine operation.
DISTRIBUTORLESS IGNITION SYSTEM (DIS)
DIS eliminates mechanical ignition components that can wear
out. PCM has complete ignition control and uses a coil pack, CMP
sensor and CKP sensor to control ignition timing. CMP sensor reads
slots in cam timing sprocket. PCM uses this information along with
information from CKP sensor to determine if fuel injectors and
ignition coils are properly sequenced for correct cylinders.
Basic timing is determined by CKP sensor position and is not
adjustable. One complete engine revolution may be required for PCM to
determine crankshaft position during cranking.
Molded ignition coils are used. Each coil fires 2 paired
spark plugs at the same time. One cylinder is on compression stroke
and other cylinder is on exhaust stroke.
HALL EFFECT IGNITION SYSTEM
This system is equipped with a Hall Effect distributor. See
Fig. 1 . Shutter(s) attached to distributor shaft rotate through
distributor Hall Effect switch, also referred to as a CMP sensor,
which contains a distributor pick-up (a Hall Effect device and
magnet). As shutter blade(s) pass through pick-up, magnetic field is
interrupted and voltage is toggled between high and low. PCM uses this
cylinder position data from CMP sensor, along with engine speed (RPM)
and CKP sensor data, to control ignition timing and injector pulse
width to maintain optimum driveability.
EMISSION SYSTEMS
Vehicles are equipped with different combinations of emission
system components. Not all components are used on all models. To
determine component usage on a specific model, see EMISSION
APPLICATIONS - TRUCKS article.
AIR INJECTION SYSTEM
This system adds a controlled amount of air to exhaust gases,
through air relief valve and check valves, to assist oxidation of
hydrocarbons and carbon monoxide in exhaust stream. Air is injected at
catalytic converters.
CRANKCASE VENTILATION (CCV) SYSTEM
CCV system performs same function as a conventional Positive