100-04-4 Noise, Vibration and Harshness 100-0414
DIAGNOSIS AND TESTING
Noise, Vibration and Harshness (NVH)
Inspection and Verification
1. Verify the customer concern. Identify the Condition
2. Visually inspect for obvious signs of mechanical NVH usually occur in four areas:
or electrical damage.
tires
3. If an obvious cause for an observed or reported
concern is found, correct the cause (if possible) engine accessories
before proceeding to the next step.
suspension
4. If the concern is not visually evident, verify the
symptom and REFER to the Symptom Chart.
How to Use this Diagnostic Procedure
Section
Noise, vibration and harshness (NVH) concerns
have become more important as
vehjcles have
become more sensitive to these vibrations. This
section is designed to aid in identifying these
concerns.
The section provides diagnostic procedures based on symptom. If the condition occurs at
high speed, for instance, the most likely place
to start is under Shake and Vibration While
Driving.
The road test procedure will tell how to sort the
conditions into categories and how to tell a
vibration from a shake.
A series of Road Test Quick Checks are
provided to make sure that a cause is either
pinpointed or eliminated.
Name the condition, proceed to the appropriate
section and locate the correct diagnosis. When
the condition is identified, the job is partly done.
Follow the diagnostic procedure as outlined.
Quick Checks are described within the step,
while more involved tests and adjustments are
outlined in General Procedures.
Always follow each step exactly and make notes
to recall important findings later.
driveline
It is important, therefore, that an NVH concern be
isolated into its specific
area(s) as soon as
possible. The easiest and quickest way to do this
is to carry out the Road Test as outlined. To assist
in the diagnosis and testing
procedure(s), use a
suitable approved NVH diagnosis tester.
Noise Diagnostic Procedure
Non-Axle Noise
The five most common sources of non-axle noise
are exhaust, tires, roof racks, trim panels and
( transmission.
Therefore, make sure that none of the following
conditions are the cause of the noise before
proceeding with a driveline
teardown and
diagnosis.
In certain conditions, the pitch of the exhaust
may sound very much like gear noise. At other
times, it can be mistaken for a wheel bearing
rumble.
Tires, especially snow tires, can have a high
pitched tread whine or roar, similar to gear
noise. Radial tires may have this characteristic.
Also, any non-standard tire with an unusual
tread construction may emit a roar or whine
noise.
Trim panels can also cause whistling or whining
noise.
Clunk may be a metallic noise heard when the
Customer Interview automatic transaxle is engaged in "R
(REVERSE) or "D" (DRIVE) or it may occur
The road test and customer interview (if available) when
the throttle is applied or released. It is
provide information that will help identify the caused
by backlash somewhere in the driveline.
,
concern and will provide direction to the correct Bearing rumble sounds like marbles being
starting point for diagnosis. (
tumbled. This condition is usually caused by a
damaged wheel bearing.
2006.0 Fiesta 1212006 G37349en
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Fuel Charging and Controls - 2.OL
303-04B-13 Duratec-HE (M14) 303-04B-13
DIAGNOSIS AND TESTING
Possible Sources Action
,
Engine ignition.
Symptom
Engine stumbling
Engine lacks power
REFER to: Engine lgnition
(303-07B, Diagnosis and
Testing).
Fuel injectors.
INSPECT the fuel injectors.
CLEAN the fuel injectors or
INSTALL a new set of injectors
as required only after the
checks have been carried out.
Low fuel system pressure.
EGR valve sticking open.
Check the fuel system pres-
sure.
REFER to: Fuel System Pres-
sure Check (31
0-OOA,
General Procedures).
Fuel rail fuel pressure sensor.
REFER to: Engine Emission
Control (303-08 Engine
Emission Control
- 2.OL
Duratec-HE (M14), Diagnosis
and Testing).
Carry out a full engine
diagnosis using the guided
diagnostic menu in WDS.
Engine ignition. REFER to: Engine lgnition
(303-07B, Diagnosis and
Testing).
Brakes binding.
I CHECK the braking system.
REFER to: Brake System (206-
1 00, Diagnosis and Testing).
Vehicle overloaded, or
excessive wind resistance (roof
racks, towing etc). ADVISE
the customer about
the effects of overloading the
vehicle and wind resistance on
the fuel consumption.
Air cleaner element blocked.
REFER to: Fuel System Pres-
sure Check (31
0-OOA,
General Procedures).
INSTALL a new air cleaner
element as necessary.
Low fuel system pressure.
r
Check the fuel system pres-
sure.
2006.0 Fiesta 1212006 GI 65371 en
Kinked or restricted fuel lines. INSPECT the fuel lines.
INSTALL new components as
necessary. TEST the system
for normal operation.
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Fuel Charging and Controls - 2.OL
303-04B-22 Duratec-HE (M14) 303-04B-22
DIAGNOSIS AND TESTING
Symptom
Engine knock during accelera-
tion Possible
Sources Action
CKP sensor. Carry out a full engine
diagnosis using the guided
diagnostic menu in WDS.
INSPECT the fuel injectors.
CLEAN the fuel injectors or
INSTALL a new set of injectors
as required only after the
checks have been carried out.
I . Incorrect valve timing. I CHECK the valve timing. I
Excessive carbon build up. REMOVE the cylinder head.
INSPECT the cylinder head
and pistons for signs carbon
build up.
REFER to: Cylinder Head (303-
01 C, In-vehicle Repair).
Worn or damaged oil pump.
Worn or damaged timing chain
or sprocket.
Major mechanical engine
failure. INSPECT
the engine compon- I
ents.
KS.
Fuel injectors. Carry out a full engine
diagnosis using the guided
diagnostic menu in WDS.
INSPECT the fuel injectors.
CLEAN the fuel injectors or
INSTALL a new set of injectors
as required only after the
checks have been carried out.
Major mechanical engine
failure. REFER
to: Engine (303-01
Engine
- 2.OL Duratec-HE
(M14), Diagnosis and
Testing).
N0TE:Before proceeding with any
of the actions in relation to the
possible sources for excessive
fuel consumption, a fuel consumption test located in the
toolbox menu of WDS must be
performed.
Excessive fuel consumption Brakes binding. CHECK
the braking system.
REFER to: Brake System (206-
00, Diagnosis and Testing).
Vehicle overloaded, or
excessive wind resistance (roof
racks, towing etc).
ADVISE the customer about
the effects of overloading the
vehicle and wind resistance on
the fuel consumption.
2006.0 Fiesta 1212006 GI 65371 en
Air cleaner element blocked. INSTALL a new air cleaner .-
element. I
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