Pinpoint Test D: The Generator is Noisy

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Charging System for schematic and connector information.

Normal Operation 

The generator is belt-driven by the engine accessory drive system.

This pinpoint test is intended to diagnose the following:

• Accessory drive belt
• Loose bolts/brackets
• Generator/pulley

PINPOINT TEST D: THE GENERATOR IS NOISY 

1. D1 CHECK FOR ACCESSORY DRIVE BELT NOISE AND LOOSE MOUNTING BRACKETS 
   • Key in OFF position.
   • Check the accessory drive belt for damage and correct installation. Refer to ACCESSORY DRIVE article.
   • Check the accessory mounting brackets and generator pulley for looseness or misalignment.
   • Is the accessory drive OK? 
   1. YES  : Go to  D2.
   2. NO  : REPAIR as necessary. REFER to ACCESSORY DRIVE article for diagnosis and testing of the accessory drive system. TEST the system for normal operation.
2. D2 CHECK THE GENERATOR MOUNTING 
   • Check the generator mounting for loose bolts or misalignment.
   • Is the generator mounted correctly? 
   1. YES  : Go to  D3.
   2. NO  : REPAIR as necessary. TEST the system for normal operation.
3. D3 CHECK THE GENERATOR FOR ELECTRICAL NOISE 
   • Disconnect: Generator C102b
   • Key in START position.
   • With the engine running, use a stethoscope or equivalent listening device to probe the generator.
   • Is the noise still present? 
   1. YES  : Go to  D4.
   2. NO  : INSTALL a new generator. REFER to GENERATOR & REGULATOR article. TEST the system for normal operation.
4. D4 CHECK THE GENERATOR FOR MECHANICAL 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? 
   1. YES  : INSTALL a new generator. REFER to GENERATOR & REGULATOR article. TEST the system for normal operation.
   2. NO  : REFER to ENGINE SYSTEM - GENERAL INFORMATION article to diagnose the source of the engine noise.