2003 FORD MUSTANG check engine

z
Did any abnormal occurrence coincide with or proceed its appearance?
Use the information gained from the customer to accurately begin the diagnostic process.
Pre- Drive Check
It is important to do a pre- drive check before road testing the vehicle. A pre- drive check verifies that
the vehicle is relatively safe to drive and eliminates any obvious faults on the vehicle.
The pre- drive check consists of a brief visual inspection. During this brief inspection, take note of
anything that will compromise safety during the road test and make those repairs/adjustments before
taking the vehicle on the road.
Preparing for the Road Test
Observe the following when preparing for the road test:
zReview the information recorded on the NVH Diagnostic Guide. It is important to know the
specific concern the customer has with the vehicle.
z Do not be misled by the reported location of the noise/vibration. The cause can actually be
some distance away.
z Remember that the vibrating source component (originator) may only generate a small
vibration. This small vibration can in turn cause a larger vibration/noise to emanate from another
receiving component (reactor), due to contact with other components (transfer path).
z Conduct the road test on a quiet street where it is safe to duplicate the vibration/noise. The ideal
testing route is an open, low- traffic area where it is possible to operate the vehicle at the speed
in which the condition occurs.
z If possible, lower the radio antenna in order to minimize turbulence. Identify anything that could
potentially make noise or be a source of wind noise. Inspect the vehicle for add- on items that
create vibration/noise. Turn off the radio and the heating and cooling system blower.
z The engine speed is an important factor in arriving at a final conclusion. Therefore, connect an
accurate tachometer to the engine, even if the vehicle has a tachometer. Use a tachometer that
has clearly defined increments of less than 50 rpm. This ensures an exact engine speed
reading.
Verify the Customer Concern
Verify the customer concern by carrying out a road test, an engine run- up test, or both.
The decision to carry out a road test, an engine run- up test, or both depends on the type of NVH
concern. A road test may be necessary if the symptom relates to the suspension system or is sensitive
to torque. A drive engine run- up (DERU) or a neutral engine run- up (NERU) test identifies noises and
vibrations relating to engine and drivetrain rpm. Remember, a condition will not always be identifiable
by carrying out these tests, however, they will eliminate many possibilities if carried out correctly.
Road Test Klj . 5 ba
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NOTE:
A serpentine drive belt decreases the usefulness of this test. In these cases, use a
vibration analyzer, such as the VA, to pinpoint accessory vibrations. An electronic listening
device, such as an EngineEAR, will also help to identify noises from specific accessories.
Remove the accessory drive belts.
z Increase the engine rpm to where the concern occurs.
z If the vibration/noise is duplicated when carrying out this test, the belts and accessories are not
sources.
z If the vibration/noise was not duplicated when carrying out this test, install each accessory belt,
one at a time, to locate the source.
Vehicle Cold Soak Procedure
To carry out this procedure, proceed as follows:
zTest preparations include matching customer conditions (if known). If not known, document the
test conditions: gear selection and engine rpm. Monitor the vibration/noise duration with a watch
for up to three minutes.
z Park the vehicle where testing will occur. The vehicle must remain at or below the concern
temperature (if known) for 6- 8 hours.
z Before starting the engine, conduct a visual inspection under the hood.
z Turn the key on, but do not start the engine. Listen for the fuel pump, anti- lock brake system
(ABS) and air suspension system noises.
z Start the engine.
z CAUTION: Never probe moving parts.
Isolate the vibration/noise by carefully listening. Move around the vehicle while listening to find
the general location of the vibration/noise. Then, search for a more precise location by using a
stethoscope or EngineEAR.
z GO to Symptom Chart — Idle Noise/Vibration to assist with the diagnosis.
6: Check OASIS/TSBs/Repair History
After verifying the customer concern, check for OASIS reports, TSBs and the vehicle repair history for
related concerns. If information relating to a diagnosis/repair is found, carry out the procedure(s)
specified in that information.
If no information is available from these sources, carry out the vehicle preliminary inspection to
eliminate any obvious faults.
7: Diagnostic Procedure
Qualifying the concern by the particular sensation present can help narrow down the concern. Always
use the "symptom" to "system" to "component" to "cause" diagnosis technique. This diagnostic method
divides the problem into related areas to correct the customer concern.
zVerify the "symptom".
z Determine which "system(s)" can cause the "symptom".
„If a vibration concern is vehicle speed related, the tire and wheel rpm/frequency or
driveshaft frequency should be calculated.
„ If a vibration concern is engine speed related, the engine, engine accessory or engine
firing frequencies should be calculated. Klj . 9 ba
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components as necessary.
z Broken
powertrain
mounts. z
INSPECT the powertrain
mounts. INSTALL new
mounts as necessary.
REFER to Section 303 - 01A
for 3.8L engines or
Section 303 - 01B for 4.6L (2V)
engines.
z Idle speed too
high. z
CHECK for the correct idle
speed.
z Driveline clunk—
occurs as the vehicle
starts to move
forward following a
stop z
Worn or galled
driveshaft slip-
yoke splines. z
CLEAN and INSPECT the
splines of the yoke for a
worn or galled condition.
INSTALL a new yoke as
necessary. REFER to
Section 205 - 01 .
z Worn or galled
driveshaft and
coupling shaft
splines. z
CLEAN and INSPECT the
splines of the driveshaft and
coupling shaft for a worn or
galled condition. INSTALL a
new driveshaft assembly as
necessary. REFER to
Section 205 - 01 .
z Loose rear leaf
spring U- bolts. z
CHECK the U- bolts for
loose nuts. TIGHTEN to
specification. REFER to
Section 204 - 02 .
z Driveline clunk (FWD
vehicles)—occurs
during acceleration or
from cruise to
coast/deceleration z
Damaged or
worn inboard
constant velocity
(CV) joint. z
INSPECT the inboard CV
joint and boot. REPAIR or
INSTALL a new CV joint as
necessary.
z Driveline clunk (4WD
vehicles)—occurs
during shift- on-the- fly
engagement z
Clutch relay.
z Shift motor.
z Transfer case.
z GEM. z
CHECK the 4WD
engagement system.
REPAIR or INSTALL new
components as necessary.
z Clicking, popping or
grinding— occurs
while vehicle is
turning z
Inadequate or
contaminated
lubrication in the
(CV) joints. z
CHECK the CV boots and
joints for wear or damage.
REPAIR or INSTALL new
components as necessary.
z Another
component
contacting the
halfshaft. z
CHECK the halfshafts and
the area around the
halfshafts. REPAIR as
necessary.
z Brake
components. z
INSPECT the front brakes
for wear or damage.
REPAIR as necessary.
REFER to Section 206 - 03 .
z Steering
components. z
INSPECT the drag link,
inner and outer tie- rods or
idler arm for wear or
damage. REPAIR as
necessary. REFER to
Section 211 - 02 .
z Suspension
components. z
INSPECT the upper and
lower ball joints for wear or
damage. REPAIR as
necessary. REFER to Klj . 19 ba
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CARRY OUT a driveline
vibration test. REFER to
Section 205
- 00 . REPAIR as
necessary.
z Binding or
damaged
splines on the
driveshaft slip-
yoke. z
CLEAN and INSPECT the
splines of the slip- yoke,
driveshaft and coupling
shaft for wear or damage.
INSTALL a new slip- yoke or
driveshaft assembly as
necessary. REFER to
Section 205 - 01 . REPAIR as
necessary.
z Driveshaft
runout. z
CARRY OUT a Runout
Check. REFER to Section 205 - 00 . REPAIR as
necessary.
z Incorrect lateral
and radial
tire/wheel
runout. z
INSPECT the tire and
wheels. MEASURE tire
runouts. REPAIR or
INSTALL new components
as necessary. REFER to
Section 204 - 04 .
z Driveline angles
out of
specification. z
CHECK for correct driveline
angles. REPAIR as
necessary. REFER to
Section 205 - 00 .
z Incorrectly
seated CV joint
in the front
wheel hub. z
CHECK the outer CV joint
for correct seating into the
hub. REPAIR as necessary. Symptom Chart —
Engine Noise/Vibration Condition
Possible Sources Action
z Grinding noise—
occurs during
engine cranking z
Incorrect starter
motor mounting. z
INSPECT the starter motor
for correct mounting.
REPAIR as necessary.
REFER to Section 303 - 06 .
z Starter motor. zCHECK the starter motor.
REPAIR or INSTALL a new
starter motor as necessary.
REFER to Section 303 - 06 .
z Incorrect starter
motor drive
engagement. z
INSPECT the starter motor
drive and flexplate/flywheel
for wear or damage.
INSTALL a new starter
motor drive or flywheel as
necessary. REFER to
Section 303 - 06 .
z Engine ticking
noise z
Fuel injector.
z Fuel line.
z Oil pump.
z Valve lifter.
z Belt tensioner.
z Water pump.
z Obstruction of cooling
fan. z
Go To Pinpoint Test B .
z Engine drumming zPowertrain mount. zCARRY OUT Klj . 23 ba
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noise—
normally
accompanied by
vibration Powertrain/Drivetrain Mount Neutralizing in this
section.
z Damaged or
misaligned exhaust
system. z
INSPECT the exhaust
system for loose or broken
clamps and brackets.
CARRY OUT Exhaust System Neutralizing in this
section.
z Whistling noise—
normally
accompanied
with poor idle
condition z
Air intake system. zCHECK the air intake
ducts, air cleaner, throttle
body and vacuum hoses for
leaks and correct fit.
REPAIR or ADJUST as
necessary. REFER to
Section 303 - 12
z
Clunking noise zWater pump has
excessive end play or
imbalance. z
CHECK the water pump for
excessive end play.
INSPECT the water pump
with the drive belt off for
imbalance. INSTALL a new
water pump as necessary.
REFER to Section 303 -
03A .
z Generator has
excessive end play. z
CHECK the generator for
excessive end play.
REPAIR or INSTALL a new
generator. REFER to
Section 414 - 02 .
z Pinging noise zExhaust system leak. zINSPECT the exhaust
system for leaks. REPAIR
as necessary.
z Gasoline octane too
low. z
VERIFY with customer the
type of gasoline used.
CORRECT as necessary.
z Knock sensor
operation. z
CHECK the knock sensor.
INSTALL a new knock
sensor as necessary.
REFER to Section 303 - 14 .
z Incorrect spark
timing. z
CHECK the spark timing.
REPAIR as necessary.
z High operating
temperature. z
INSPECT cooling system
for leaks. CHECK the
coolant level. REFILL as
necessary. CHECK the
coolant for the correct mix
ratio. DRAIN and REFILL
as needed. CHECK engine
operating temperature is
within specifications.
REPAIR as necessary.
z Foul- out spark plug. zCHECK the spark plugs.
REPAIR or INSTALL new
spark plugs as necessary.
z Catalytic converter. zAcceptable noise.
z Knocking noise—
light knocking
noise, also z
Excessive clearance
between the piston
and the cylinder wall. z
Engine cold and at high
idle. Using an EngineEAR,
pull a spark plug or fuel Klj . 24 ba
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described as
piston slap. Noise
is most
noticeable when
engine is cold
with light to
medium
acceleration.
Noise disappears
as engine warms
injector connector until the
noise goes away. CARRY
OUT a cylinder bore
clearance to piston check.
INSTALL a new piston.
REFER to
Section 303 - 01A
for 3.8L engines or
Section 303 - 01B for 4.6L (2V)
engines.
z Knocking noise—
light double
knock or sharp
rap sound.
Occurs mostly
with warm engine
at idle or low
speeds in DRIVE.
Increases in
relation to engine
load. Associated
with poor
lubrication history z
Excessive clearance
between the piston
and the piston pin. z
INSTALL a new piston or
piston pin. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Knocking noise—
light knocking
noise is most
noticeable when
engine is warm.
Noise tends to
decrease when
vehicle is
coasting or in
neutral z
Excessive clearance
between the
connecting rod
bearings and the
crankshaft. z
Engine warm and at idle.
Using an EngineEAR,
PULL a spark plug or fuel
injector connector until the
noise goes away. INSTALL
new bearings. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Knocking— deep
knocking noise.
Noise is most
noticeable when
engine is warm,
at lower rpm and
under a light load
and then at float z
Worn or damaged
crankshaft main
bearings. z
CARRY OUT DERU test.
CHECK for noise with
vehicle at operating
temperature, during
medium to heavy
acceleration. CHECK at
idle with injector
disconnected, noise does
not change. INSTALL new
main bearings. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Knocking noise—
occurs mostly
with warm engine
at light/medium
acceleration z
Spark plugs. zCHECK the spark plug for
damage or wear. INSTALL
new spark plugs as
necessary.
z Carbon accumulation
in combustion
chamber. z
REMOVE carbon from
combustion chamber.
z Whine or
moaning noise z
Air intake system. zCHECK the air cleaner and
ducts for correct fit.
INSPECT the air intake
system for leaks or
damage. REPAIR as
necessary. Klj . 25 ba
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z
Generator electrical
field or bearings. z
CARRY OUT generator
load test. REPAIR or
INSTALL a new generator
as necessary. REFER to
Section 414 - 02 .
z Drone type noise zExhaust system. zCARRY OUT the Exhaust System Neutralizing in this
section. REPAIR as
necessary.
z A/C compressor. zCHECK for noise with
vehicle at constant speeds.
CYCLE the compressor on
and off and listen for a
change in pitch. REPAIR as
necessary. REFER to
Section 412 - 03 .
z Powertrain mounts. zCARRY OUT the
Powertrain/Drivetrain Mount Neutralizing in this
section.
z Sputter type
noise— noise
worse when cold,
lessens or
disappears when
vehicle is at
operating
temperature z
Damaged or worn
exhaust system
components. z
INSPECT the exhaust
system for leaks or
damage. REPAIR as
necessary. REFER to
Section 309 - 00 .
z Rattling noise—
noise from the
upper engine
(valve train).
Worse when
engine is cold z
Low oil level. zCHECK oil level. FILL as
necessary.
z Thin or diluted oil. zINSPECT the oil for
contamination. If oil is
contaminated, CHECK for
the source. REPAIR as
necessary. CHANGE the oil
and filter.
z Low oil pressure. zCARRY OUT an oil
pressure test. If not within
specifications, REPAIR as
necessary. REFER to
Section 303 - 00 .
z Worn rocker
arms/fulcrums or
followers. z
CARRY OUT a valve train
analysis. INSTALL new
valve train components as
necessary. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Worn valve guides. zCARRY OUT a valve train
analysis. INSTALL new
valve guides as necessary.
REFER to Section 303 - 01A
for 3.8L engines or
Section 303 - 01B for 4.6L (2V)
engines. Klj . 26 ba
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z
Excessive runout of
valve seats on the
valve face. z
CARRY OUT a valve seat
runout test. INSPECT the
valve face and seat.
INSTALL new valves as
necessary. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Rattling noise—
from the bottom
of the vehicle z
Loose muffler shields
or catalytic converter
shields. z
CHECK the exhaust
system for loose exhaust
shields. REPAIR as
necessary.
z Thumping
noise— from the
bottom of the
vehicle, worse at
acceleration z
Exhaust pipe/muffler
grounded to chassis. z
CHECK the exhaust
system to chassis
clearance. CHECK the
exhaust system hangers for
damage. REPAIR as
necessary. REFER to
Section 309 - 00 .
z Whoosh— occurs
during light
vehicle
acceleration.
Heard inside the
vehicle z
Throttling late,
creating turbulence
transmitted through
the plastic manifold. z
CHECK for leaks or
missing seal in the dash
panel.
z Engine
vibration—
increases
intensity as
engine rpm is
increased z
Engine out-of-
balance. z
CARRY OUT Neutral
Engine Run- Up (NERU)
Test. ROTATE the torque
converter, 120° for 3 bolt
and 180° for 4 bolt.
INSPECT the torque
converter pilot outer
diameter to crankshaft pilot
inner diameter. REPAIR as
necessary. REFER to
Section 307 - 01 .
z Engine
vibration— is felt
with increases
and decreases in
engine rpm z
Strain on exhaust
mounts. z
CARRY OUT the Exhaust
System Neutralizing
procedure in this section.
REPAIR as necessary.
z Damaged or worn
powertrain/drivetrain
mounts. z
CHECK the
powertrain/drivetrain
mounts for damage.
REPAIR as necessary.
z Engine or
transmission
grounded to chassis. z
INSPECT the
powertrain/drivetrain for
correct clearances.
REPAIR as necessary.
z Engine
vibration—
vibration felt at all
times z
Excessive engine
pulley runout. z
CARRY OUT Engine
Accessory Test. INSTALL a
new engine pulley as
necessary. REFER to
Section 303 - 01A for 3.8L
engines or Section 303 - 01B
for 4.6L (2V) engines.
z Damaged or worn
accessory
component. z
CARRY OUT Engine
Accessory Test. REPAIR or
INSTALL a new component Klj . 27 ba
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