test G FORD MUSTANG 2003 User Guide

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:
It may be necessary to have the customer ride along or drive the vehicle to point out the
concern. During the road test, take into consideration the customer's driving habits and the driving
conditions. The customer's concern just may be an acceptable operating condition for that vehicle.
The following is a brief overview of each test in the order in which it appears. A review of this
information helps to quickly identify the most appropriate process necessary to make a successful
diagnosis. After reviewing this information, select and carry out the appropriate test(s), proceeding to
the next step of this process.
zThe Slow Acceleration Test is normally the first test to carry out when identifying an NVH
concern, especially when a road test with the customer is not possible.
z The Heavy Acceleration Test helps to determine if the concern is torque- related.
z The Neutral Coast Down Speed Test helps to determine if the concern is vehicle speed- related.
z The Downshift Speed Test helps to determine if the concern is engine speed- related.
z The Steering Input Test helps to determine how the wheel bearings and other suspension
components contribute to a vehicle speed- related concern.
z The Brake Test helps to identify vibrations or noise that are brake related.
z The Road Test Over Bumps helps isolate a noise that occurs when driving over a rough or
bumpy surface.
z The Engine Run- Up Tests consist of the Neutral Run- Up Test and the Engine Load Test. These
tests help to determine if the concern is engine speed- related.
z The Neutral Run- Up Test is used as a follow- up test to the Downshift Speed Test when the
concern occurs at idle.
z The Engine Load Test helps to identify vibration/noise sensitive to engine load or torque. It also
helps to reproduce engine speed- related concerns that cannot be duplicated when carrying out
the Neutral Run- Up Test or the Neutral Coast Down Test.
z The Engine Accessory Test helps to locate faulty belts and accessories that cause engine
speed- related concerns.
z The Vehicle Cold Soak Procedure helps to identify concerns occurring during initial start- up and
when an extended time lapse occurs between vehicle usage.
Slow Acceleration Test
To carry out this test, proceed as follows:
zSlowly accelerate to the speed where the reported concern occurs. Note the vehicle speed, the
engine rpm and, if possible, determine the vibration frequency.
z Attempt to identify from what part of the vehicle the concern is coming.
z Attempt to identify the source of the concern.
z Proceed as necessary.
Heavy Acceleration Test
To carry out this test, proceed as follows:
zAccelerate hard from 0- 64 km/h (0-40 mph).
z Decelerate in a lower gear.
z The concern is torque related if duplicated while carrying out this test.
z Proceed as necessary. Klj . 6 ba
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Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
zDrive at a higher rate of speed than where the concern occurred when carrying out the Slow
Acceleration Test.
z Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
z The concern is vehicle speed- related if duplicated while carrying out this test. This eliminates
the engine and the torque converter as sources.
z If the concern was not duplicated while carrying out this test, carry out the Downshift Speed
Test to verify if the concern is engine speed related.
z Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
zShift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
z Drive at the engine rpm where the concern occurs.
z The concern is engine speed related if duplicated while carrying out this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.
z If necessary, repeat this test using other gears and NEUTRAL to verify the results.
z Proceed as necessary.
Steering Input Test
To carry out this test, proceed as follows:
zDrive at the speed where the concern occurs, while making sweeping turns in both directions.
z If the concern goes away or gets worse, the wheel bearings, hubs, U- joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.
z Proceed as necessary.
Brake Test
To carry out this test, proceed as follows:
zWarm the brakes by slowing the vehicle a few times from 80–32 km/h (50–20 mph) using light
braking applications. At highway speeds of 89–97 km/h (50– 60 mph), apply the brake using a
light pedal force.
z Accelerate to 89–97 km/h (55–60 mph).
z Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).
z A brake vibration noise can be felt in the steering wheel, seat or brake pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.
Road Test Over Bumps
To carry out this test, proceed as follows: Klj . 7 ba
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z
Drive the vehicle over a bump or rough surface one wheel at a time to determine if the noise is
coming from the front or the back and the left or the right side of the vehicle.
z Proceed as necessary.
Neutral Engine Run- Up (NERU) Test
To carry out this test, proceed as follows:
zInstall a tachometer.
z Increase the engine rpm up from an idle to approximately 4000 rpm while in PARK on front
wheel drive vehicles with automatic transmissions, or NEUTRAL for all other vehicles. Note the
engine rpm and, if possible, determine the vibration frequency.
z Attempt to identify what part of the vehicle the concern is coming from.
z Attempt to identify the source of the concern.
z Proceed as necessary.
Drive Engine Run- Up (DERU) Load Test
To carry out this test, proceed as follows:
z WARNING: Block the front and rear wheels, and apply the parking brake and the
service brake, or injury to personnel can result.
CAUTION: Do not carry out the Engine Load Test for more than five seconds or
damage to the transmission or transaxle can result.
Block the front and rear wheels.
z Apply the parking brake and the service brake.
z Install a tachometer.
z Shift the transmission into DRIVE, and increase and decrease the engine rpm between an idle
to approximately 2000 rpm. Note the engine rpm and, if possible, determine the vibration
frequency.
z Repeat the test in REVERSE.
z If the vibration/noise is duplicated when carrying out this test, inspect the engine and
transmission or transaxle mounts.
z If the concern is definitely engine speed- related, carry out the Engine Accessory Test to narrow
down the source.
z Proceed as necessary.
Engine Accessory Test
To carry out this test, proceed as follows:
z WARNING: Block the front and rear wheels, and apply the parking brake and the
service brake, or injury to personnel can result.
CAUTION: Limit engine running time to one minute or less with belts removed or
serious engine damage will result. Klj . 8 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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occurs on first
(morning) brake
application
pads.
Caused by humidity and
low disc brake pad
temperature.
z Squealing noise— a
continuous squeal z
Disc brake pads
or linings worn
below minimum
thickness. z
INSTALL new disc brake
pads. REFER to Section 206 - 03 for front disc brake
pads or Section 206 - 04 for
rear disc brake pads.
z Squealing noise— an
intermittent squeal
brought on by cold,
heat, water, mud or
snow z
Disc brake pad. zAcceptable condition.
z Groaning noise—
occurs at low speeds
with brake lightly
applied (creeping) z
Disc brake
pads. z
Acceptable condition.
z Grinding noise—
continuous z
Disc brake pads
or linings worn
below minimum
thickness. z
INSPECT the disc brake
pads, brake discs and
attaching hardware for
damage. REPAIR or
INSTALL new components
as necessary. REFER to
Section 206 - 03 for front
disc brakes and Section 206 - 04 for rear disc brakes.
z Moaning noise zBrake linings
contaminated
with grease or
oil. z
INSPECT the brake pads
and shoes for
contamination. REPAIR or
INSTALL new components
as necessary. REFER to
Section 206 - 03 for front
disc brakes or Section 206 -
04 for rear disc brakes.
z Brake
vibration/shudder—
occurs when brakes
are applied z
Uneven disc or
drum wear.
z Uneven disc
brake pad or
lining transfer.
z Suspension
components. z
Go To Pinpoint Test A .
z Brake
vibration/shudder—
occurs when the brake
pedal is released z
Brake drag. zINSPECT the disc brake
pads or linings for
premature wear. REPAIR
or INSTALL a new caliper
or wheel cylinder as
necessary. REFER to
Section 206 - 03 for front
disc brakes and Section 206 - 04 for rear disc brakes.
Symptom Chart—
Driveline Noise/Vibration Condition
Possible Sources Action
z Axle howling or
whine— front or rear
axle z
Axle lubricant
low. z
CHECK the lubricant level.
FILL the axle to
specification.
z Axle housing zINSPECT the axle housing Klj . 17 ba
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Section 204 - 01 .
z Damaged or
worn wheel
bearings z
CHECK for abnormal wheel
bearing play or roughness.
Refer to Wheel Bearing Check in this section.
ADJUST or INSTALL new
wheel bearings as
necessary.
z Clicking or
snapping— occurs
when accelerating
around a corner z
Damaged or
worn outboard
CV joint. z
INSPECT the outboard CV
joint and boot. REPAIR or
INSTALL a new CV joint as
necessary.
z High pitched
chattering— noise
from the rear axle
when the vehicle is
turning z
Incorrect or
contaminated
lubricant. z
CHECK the vehicle by
driving in tight circles (5
clockwise, 5
counterclockwise). FLUSH
and REFILL with the
specified rear axle lubricant
and friction modifier as
necessary.
z Damaged or
worn differential
(differential side
gears and pinion
gears). z
DISASSEMBLE the
differential assembly.
INSPECT the differential
case, pin and gears for wear
or damage. REPAIR or
INSTALL a new differential
as necessary. REFER to
Section 205 - 02A for Ford
7.5 rear axles or Section 205 - 02B for Ford 8.8
integral axles.
z Buzz—buzzing noise
is the same at cruise
or coast/deceleration z
Damaged or
worn tires. z
CHECK for abnormal tire
wear or damage. INSTALL a
new tire as necessary.
REFER to Section 204 - 04 .
z Incorrect
driveline angles. z
CHECK for correct driveline
angles. REPAIR as
necessary. REFER to
Section 205 - 00 .
z Rumble or boom—
noise occurs at
coast/deceleration,
usually driveshaft
speed related and
noticeable over a
wide range of speeds z
Driveshaft is
out-of- balance. z
CHECK the driveshaft for
damage, missing balance
weights or undercoating.
CHECK the driveshaft
balance. CARRY OUT a
driveline vibration test.
REFER to Section 205 - 00 .
z U-joints binding
or seized. z
ROTATE the driveshaft and
CHECK for rough operation
or seized U- joints. INSTALL
new U- joints as necessary.
REFER to Section 205 - 01 .
z Excessive
pinion flange
runout. z
CARRY OUT a runout
check. REPAIR as
necessary. REFER to
Section 205 - 00 .
z Grunting— normally
associated with a
shudder experienced
during acceleration z
Driveshaft slip
yoke binding. z
CLEAN and LUBRICATE
the male and female
splines. Klj . 20 ba
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from a dead stop
zLoose rear
spring U- bolts. z
INSPECT the rear
suspension. TIGHTEN the
U-bolt nuts to specification.
REFER to Section 204 - 02 .
z Howl— can occur at
various speeds and
driving conditions.
Affected by
acceleration and
deceleration z
Incorrect ring
and pinion
contact,
incorrect
bearing preload
or gear damage. z
CHECK the ring and pinion
and bearings for damage.
INSPECT the ring and
pinion wear pattern. REFER
to Checking Tooth Contact
Pattern and Condition of the
Ring and Pinion component
test in this section. ADJUST
or INSTALL new
components as necessary.
REFER to Section 205 - 02A
for Ford 7.5 rear axles or
Section 205
- 02B for Ford
8.8 integral axles.
z Chuckle— heard at
coast/deceleration.
Also described as a
knock z
Incorrect ring
and pinion
contact or by
damaged teeth
on the coast
side of the ring
and pinion. z
CHECK the ring and pinion
for damage. INSPECT the
ring and pinion wear pattern.
REFER to Checking Tooth
Contact Pattern and
Condition of the Ring and
Pinion component test in
this section. ADJUST or
INSTALL new components
as necessary. REFER to
Section 205 - 02A for Ford
7.5 rear axles or Section 205 - 02B for Ford 8.8
integral axles.
z Knock— noise occurs
at various speeds.
Not affected by
acceleration or
deceleration z
Gear tooth
damage to the
drive side of the
ring and pinion. z
CHECK the differential case
and ring and pinion for
damage. INSTALL new
components as necessary.
REFER to Section 205 - 02A
for Ford 7.5 rear axles or
Section 205
- 02B for Ford
8.8 integral axles.
z Excessive axle
shaft end play.
(Vehicles with
integral axles). z
CHECK the axle end play
using a dial indicator.
INSTALL a new axle shaft
or side gears as necessary.
REFER to Section 205 - 02A
for Ford 7.5 rear axles or
Section 205
- 02B for Ford
8.8 integral axles.
z Scraping noise— a
continuous low
pitched noise starting
at low speeds z
Worn or
damaged pinion
bearings. z
CHECK the pinion bearings.
INSTALL new pinion
bearings as necessary.
REFER to Section 205 - 02A
for Ford 7.5 rear axles or
Section 205
- 02B for Ford
8.8 integral axles.
z Driveline shudder—
occurs during
acceleration from a
slow speed or stop z
Rear drive axle
assembly
mispositioned. z
CHECK the axle mounts
and the rear suspension for
damage or wear. REPAIR
as necessary. Klj . 21 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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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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