This section describes the techniques and procedures for
correcting the following types of vibrations:
• | Engine firing frequency |
Identifying the Concern
The first step in diagnosing a vibration concern is to identify the
exact vibration that concerns the customer.
Sometimes the vibration can be duplicated at a given speed. Other vibrations
may not be as evident and may require questioning the customer carefully.
Perform a road test with the customer in the vehicle in order to determine
the specific vibration complaint.
Ask the following questions when attempting to identify a vibration
complaint:
• | At what speed is the vibration the worst? |
• | Can the customer feel the vibration? If so, where? |
• | Can the customer hear the vibration? |
• | Does the engine or the vehicle load affect the vibration? |
• | Does the vibration occur in more than one gear range? |
• | When did the vibration first appear? |
The answers to these questions will help in duplicating and diagnosing
the vibration.
If you suspect that the vibration is normal, compare the vibration with
a vehicle that is equipped in the same way, including the following factors:
• | Engine driven accessories |
• | Suspension performance type |
Important: Do NOT attempt to repair a normal condition, or the customer will probably
be convinced that the vehicle has a problem. Customer satisfaction becomes
extremely difficult after this point.
If necessary, ride with the customer. Make the comparison with the customer
present and explain the situation.
Duplicate the Condition
All vehicles produce vibrations. Some vibrations are normal, while others
are not. Some vibrations can be repaired, some cannot. Duplicate or experience
the customer's complaint. Evaluate the vibration and the cause of the vibration
under changing conditions. Otherwise, you cannot know for certain that you
are fixing what the customer would like fixed.
The symptoms and characteristics of a noise or vibration are also important
information. Ask yourself the following questions before you begin:
• | What does the vibration feel like? |
• | Does the vibration make noise? If so, what does the vibration
sound like? |
Different types of noise and vibration have particular characteristics.
These characteristics will help determine the cause of the condition and the
best way to correct the condition.
A Process of Elimination
You must understand a few basic concepts before attempting to diagnose
a vibration. As in any diagnostic process, you must perform the following
steps:
• | Decipher the information |
• | Make your correction based on the results |
Road test the vehicle and inspect the vehicle in a manner which systematically
eliminates different components. This process supplements the information
which you have received from the customer concerning the complaint. Concentrating
efforts on the areas that have not been eliminated will make repairs faster
and more effective.