GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Alternator

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ALTERNATOR PRECAUTIONS




CAUTION
To prevent damage to the alternator and possible to yourself, the following precautions should be taken when working with the electrical system.

  1. Never reverse the battery connections.
  2.  
  3. Booster batteries for starting must be connected properly: positive-to-positive (+) and negative-to-negative (-).
  4.  
  5. Disconnect the battery cables before using a fast charger; the charger has a tendency to force current through the diodes in the opposite direction for which they were designed. This burns out the diodes.
  6.  
  7. Never use a fast charger as a booster for starting the vehicle.
  8.  
  9. Never disconnect the voltage regulator while the engine is running.
  10.  
  11. Avoid long soldering times when replacing diodes or transistors. Prolonged heat is damaging to AC (alternating current) alternators.
  12.  
  13. Do not use test lamps of more than 12 volts (V) for checking diode continuity.
  14.  
  15. Do not short across or ground any of the terminals of the AC (alternating current) alternator.
  16.  
  17. The polarity of the battery, alternator, and regulator must be matched and considered before making any electrical connections within the system.
  18.  
  19. Never operate the alternator on an open circuit. Make sure that all connections within the circuit are clean and tight.
  20.  
  21. Disconnect the battery terminals when performing any service on the electrical system. This will eliminate the possibility of accidental reversal of polarity.
  22.  
  23. Disconnect the battery ground cable if arc welding is to be done on any part of the car.
  24.  

TESTING



The cs-130, used in all 1990 C-body cars and 1991-93 base cars, is rated at 105 amps output. The cs-144, used in more luxurious 1991-93 cars with lots of electric options (designated `ua1' by gm), is rated at 140 amps output.

If the charging system is inadequate, first check the serpentine belt and tensioner. The drive belt tensioner can control the belt tension over a wide range of belt lengths; however, there are limits to the tensioners ability to compensate for various belt lengths. Installing the wrong size belt and using the tensioner outside of its operating range can result in poor tension control and damage to the tensioner, drive belt and driven components.

The alternator used on these cars is not serviceable, should not disassembled, and must be serviced as a complete unit. Internal repair parts, including the regulator, are not currently available.

  1. With a fully charged battery, properly connect a volt meter, ammeter, and carbon pile to the battery.
  2.  
  3. Start the engine and observe the voltage. It should be approximately 13.5 volts. If the voltage soars above 16 volts, the rotor field and/or regulator is defective. If the voltage is below 12 volts, the battery should be charged or replaced.
  4.  
  5. Increase engine speed and use the carbon pile to apply a load until the maximum output amps is attained. Maintain voltage above 13 volts.
  6.  
  7. If alternator output is within 15 amps of its rate output, it may be considered acceptable.
  8.  

REMOVAL & INSTALLATION





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Fig. Fig. 1 Alternator and related items-Vins C & L engines



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Fig. Fig. 2 Alternator and related items-Vin 1 engine

3.8L ENGINE
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the belt guard or other items as required.
  4.  
  5. Take careful note of the belt's routing; it must go back in exactly the same position when installed or things may rotate backwards. Lift or rotate the tensioner using an 18mm box end wrench on the pulley nut.
  6.  
  7. Remove the belt.
  8.  
  9. Remove the electrical connector from the top or back of the alternator.
  10.  
  11. Remove the nut and the positive battery connector from the bat terminal.
  12.  
  13. Remove the alternator mounting hardware, and remove the alternator from the vehicle.
  14.  

To install:

  1. Install the alternator into position. Tighten the mounting hardware to 21 ft. lbs. (29 Nm) using the following sequence:
  2.  
    1. Alternator attaching bolt to the dis mounting bracket/rear brace.
    2.  
    3. Alternator brace bolt to engine.
    4.  
    5. Make sure that tightening the bolts does not bind alternator.
    6.  

  3. Connect the electrical connections.
  4.  
  5. Lift the tensioner, and install the belt onto pulleys.
  6.  

Double check the routing of the belt(s) for correct routing.

 
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