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:
- Accessory drive belt
- 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 Drive Belts, Mounts, Brackets and Accessories.
- 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 Drive Belts, Mounts, Brackets and Accessories 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 - Gasoline Engines procedure.

No
REFER to Engine to diagnose the source of the engine noise.

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