2003 FORD MUSTANG torque

starting point.
Decibel
A unit of measurement, referring to sound pressure level, abbreviated dB.
Drive Engine Run-
Up (DERU) Test
The operation of the engine through the normal rpm range with the vehicle standing still, the brakes
applied and the transmission engaged. This test is used for noise and vibration checks.
Driveline Angles
The differences of alignment between the transmission output shaft, the driveshaft, and the rear axle
pinion centerline.
Driveshaft
The shaft that transmits power to the rear axle input shaft (pinion shaft). In a two- piece driveshaft, it is
the rearmost shaft.
Drivetrain
All power transmitting components from the engine to the wheels; includes the clutch or torque
converter, the transmission, the transfer case, the driveshaft, and the front or rear drive axle.
Drivetrain Damper
A weight attached to the engine, the transmission, the transfer case, or the axle. It is tuned by weight
and placement to absorb vibration.
Drone
A low frequency (100- 200 Hz) steady sound, like a freezer compressor. Also described as a moan.
Drumming
A cycling, low-frequency (20- 100 Hz), rhythmic noise often accompanied by a sensation of pressure on
the ear drums. Also described as a low rumble, boom, or rolling thunder. Dynamic Balance Klj . 5 ba
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„
Frequencies have a range of plus or minus 2. A reading of 10 Hz can be displayed as an
8 Hz through 12 Hz.
d. Place the vibration sensor on or near the suspect area outside the vehicle.
e. Continue the road test, driving the vehicle at the speed the symptom occurs, and take another reading.
f. Compare the readings.
„A match in frequency indicates the problem component or area.
„ An unmatched test could indicate the concern is caused by the engine, torque converter,
or engine accessory. Use the EVA in the rpm mode and check if concern is rpm related.
„ Example: A vibration is felt in the seat. Place the sensor on the console. Record the
readings. Place the vibration sensor on the rear axle. Compare the readings. If the
frequencies are the same, the axle is the problem component.
Vibrate Software®
Vibrate Software® ( Rotunda tool number 215- 00003) is a diagnostic aid which will assist in pinpointing
the source of unacceptable vibrations. The engine's crankshaft is the point of reference for vibration
diagnosis. Every rotating component will have an angular velocity that is faster, slower, or the same as
the engine's crankshaft. Vibrate Software® calculates the angular velocity of each component and
graphically represents these velocities on a computer screen and on a printed vibration worksheet.
The following steps outline how Vibrate Software® helps diagnose a vibration concern:
zEnter the vehicle information. Vibrate will do all the calculations and display a graph showing
tire, driveshaft and engine vibrations.
z Print a Vibration Worksheet graph. The printed graph is to be used during the road test.
z Road test the vehicle at the speed where the vibration is most noticeable. Record the vibration
frequency (rpm) and the engine rpm on the worksheet graph. The point on the graph where the
vibration frequency (rpm) reading and the engine rpm reading intersect indicates the specific
component group causing the concern.
„An EVA or equivalent tool capable of measuring vibration frequency and engine rpm will
be needed.
z Provide pictures of diagnostic procedures to aid in testing components.
Combination EngineEAR/ChassisEAR
An electronic listening device used to quickly identify noise and the location under the chassis while
the vehicle is being road tested. The ChassisEARs can identify the noise and location of
damaged/worn wheel bearings, CV joints, brakes, springs, axle bearings or driveshaft carrier bearings.
EngineEAR Basic Unit
An electronic listening device used to detect even the faintest noises. The EngineEARs can detect the
noise of damaged/worn bearings in generators, water pumps, A/C compressors and power steering
pumps. They are also used to identify noisy lifters, exhaust manifold leaks, chipped gear teeth and for
detecting wind noise. The EngineEAR has a sensing tip, amplifier, and headphones. The directional
sensing tip is used to listen to the various components. Point the sensing tip at the suspect component
and adjust the volume with the amplifier. Placing the tip in direct contact with a component will reveal
structure-borne noise and vibrations, generated by or passing through, the component. Various
volume levels can reveal different sounds.
Ultrasonic Leak Detector
The Ultrasonic Leak Detector is used to detect wind noises caused by leaks and gaps in areas where
there is weather- stripping or other sealing material. It is also used to identify A/C leaks, vacuum leaks Klj . 12 ba
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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
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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as necessary.
z Accelerator pedal
vibration— felt
through the pedal
as a buzz z
Throttle cable loose
or misrouted. z
INSPECT the throttle cable.
REPAIR as necessary.
REFER to Section 310 - 02 .
z Engine
vibration— mostly
at coast/neutral
coast. Condition
improves with
vehicle
accelerating z
Combustion
instability. z
CHECK the ignition system.
INSTALL new components
as necessary.
z Engine vibration
or shudder—
occurs with light
to medium
acceleration
above 56 km/h
(35 mph) z
Worn or damaged
spark plugs. z
INSPECT the spark plugs
for cracks, high resistance
or broken insulator.
INSTALL a new spark plug
(s) as necessary.
z Plugged fuel injector. zREPAIR or INSTALL a new
injector as necessary.
REFER to Section 303 - 04A
for 3.8L engines or
Section 303 - 04B for 4.6L (2V)
engines.
z Damaged spark plug
wire. z
INSPECT the spark plug
wires for damage. INSTALL
a new spark plug wire(s) as
necessary.
z Contaminated fuel. zINSPECT the fuel for
contamination. DRAIN the
fuel system and refill.
z Worn or damaged
torque converter. z
CHECK the torque
converter. INSTALL a new
torque converter as
necessary. REFER to
Section 307 - 01 .
Symptom Chart—
Idle Noise/Vibration Condition
Possible Sources Action
z Idle air control (IAC)
valve moan — occurs
on throttle tip- out z
IAC valve is
contaminated
with oil. z
GO to Component Tests in
this section.
z Accessory drive belt
chirp — occurs at idle
or high idle, cold or
hot. Most common
occurrence is during
humid weather z
Accessory drive
belt worn, or
pulley is
misaligned or
loose. z
INSPECT for loose or
misaligned pulleys. CHECK
the drive belt for wear or
damage. INSTALL new
pulley(s)/drive belt, or
accessory drive components
as necessary. REFER to
Section 303 - 05 .
z Accessory drive
bearing hoot —
occurs at idle or high
idle in cold
temperatures of
approximately +4°C z
Accessory drive
idler or
tensioner pulley
bearing is
experiencing
stick/slip z
Go To Pinpoint Test C . Klj . 28 ba
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high idle during the
first cold start of the
day
lifter/lash
adjuster).
z A continuous, speed-
dependent rattle from
the engine — occurs
during idle or high idle
during the first cold
start of the day and
disappears as the
engine warms up z
Piston noise or
valvetrain noise
(bled down
lifter/lash
adjuster). z
Go To Pinpoint Test G .
z Idle vibration—a low-
frequency vibration (5-
20 Hz) or mild shake
that is felt through the
seat/floorpan z
Cylinder misfire. zUsing a scan tool, CHECK
the ignition system. CARRY
OUT a cylinder power test.
REFER to Section 303 - 00 .
z Engine or
torque
converter out of
balance. z
VERIFY the torque
converter to crankshaft pilot
clearance is correct,
REPAIR as necessary. RE-
INDEX the torque converter
on the flex plate by 120° on
a 3 bolt converter or 180° for
a 4 bolt converter. REFER to
Section 307 - 01 . RETEST
the vehicle.
z Idle vibration—a high-
frequency vibration
(20–80 Hz) or buzz,
that is felt through the
steering wheel or seat z
Exhaust system
mounts bound
up. z
VERIFY concern occurs at
engine firing frequency.
CHECK that the exhaust
system vibrates at the same
frequency as the engine.
ADD 9– 14 km (20–30 lb.) to
the tail pipe to test, CARRY
OUT Exhaust System Neutralizing in this section.
z Body mounts
loose. z
INSPECT the body mounts.
REPAIR as necessary.
z Power steering
lines grounded
out. z
INSPECT that the power
steering lines are not
contacting the chassis or
each other. REPAIR as
necessary. Symptom Chart—
Squeak and Rattle Condition
Possible Sources Action
z Squeak— heard
inside the vehicle
when
closing/opening
the door z
Insufficient
lubrication on
the door hinge
or check strap. z
LUBRICATE the hinge or check
strap.
z Internal door
components
loose, rubbing or
misaligned. z
CHECK the inside of the door.
TIGHTEN or ALIGN as
necessary. USE the Rotunda
Squeak and Rattle Kit to isolate
any rubbing components.
z Squeak— heard
inside the vehicle
when z
Worn or
damaged glass
run/channel. z
REPAIR or INSTALL a new
glass run/channel. REFER to
Section 501 - 11 . Klj . 31 ba
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