Pinpoint Test F: The Generator is Noisy

Pinpoint Test





Pinpoint Test F: The Generator is Noisy

Normal Operation

The generator is belt-driven by the engine accessory drive system. There are many sources of generator noise including: bearing noise, electrical fault noise generator pulley or belt misalignment. A generator with certain types of diode or stator failures may also produce an audible noise.

This pinpoint test is intended to diagnose the following:
- Front End Accessory Drive (FEAD)
- Loose bolts/brackets
- Generator/pulley


PINPOINT TEST F: THE GENERATOR IS NOISY

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F1 CHECK FOR ACCESSORY DRIVE BELT NOISE AND LOOSE MOUNTING BRACKETS


- Ignition OFF.
- Check the accessory drive belt and tensioner for damage and correct installation. Refer to Accessory Drive Initial Inspection and Diagnostic Overview.
- Check the accessory mounting brackets and generator pulley for looseness or misalignment.
- Is the accessory drive OK?

Yes
GO to F2.

No
REPAIR as necessary. REFER to Accessory Drive Initial Inspection and Diagnostic Overview for diagnosis and testing of the accessory drive system. TEST the system for normal operation.

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F2 CHECK THE GENERATOR MOUNTING


- Check the generator mounting for loose bolts or misalignment.
- Is the generator mounted correctly?

Yes
GO to F3.

No
REPAIR as necessary. TEST the system for normal operation.

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F3 CHECK THE GENERATOR FOR NOISE


- With the engine running, use a stethoscope or equivalent listening device to probe the generator and the accessory drive area for unusual mechanical noise.
- Is the generator the noise source?

Yes
INSTALL a new generator. REFER to the Generator Service and Repair.

No
REFER to Engine System - General Information Initial Inspection and Diagnostic Overview to diagnose the source of the engine noise.

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