GM Prizm/Nova 1985-1993 Repair Guide

Alternator

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ALTERNATOR PRECAUTIONS



Several precautions must be observed with alternator equipped vehicles to avoid damaging the unit. They are as follows:

  1. If the battery is removed or disconnected for any reason, make sure that it is reconnected with the correct polarity. Reversing the battery connections may result in damage to the one-way rectifiers.
  2.  
  3. When utilizing a booster battery as a starting aid, always connect it as follows: positive to positive, and negative (booster battery) to a good ground on the engine of the car being started.
  4.  
  5. Never use a fast charger as a booster to start a car with an alternator.
  6.  
  7. When servicing the battery with a fast charger, always disconnect the car battery cables.
  8.  
  9. Never attempt to polarize an alternator.
  10.  
  11. Never apply more than 12 volts when attempting to jump start the vehicle. Many road service vehicles use 2 batteries connected in series to provide power - this 24 volt surge can destroy an electrical system instantly.
  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 on the 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 disconnect the alternator or the battery with the engine running.
  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 (such as body repair) is to be done on any part of the car.
  24.  

Noise from an alternator may be caused by a loose drive pulley, a loose belt, loose mounting bolts, worn or dirty bearings or worn internal parts. A high frequency whine that is heard at high engine speed or full alternator output is acceptable and should not be considered a sign of alternator failure.

TESTING - ON VEHICLE INSPECTION



  1. Inspect the battery specific gravity and electrolyte level. Check the specific gravity of each cell. The standard specific gravity of each cell is 1.25-1.27 when fully charged at 68°F. On a Delco battery with a maintenance eye look for a GREEN DOT which means the battery is fully charged. The DARK eye (GREEN DOT NOT VISIBLE) means the battery must be charged. The CLEAR or LIGHT YELLOW eye means replace the battery.
  2.  
  3. Make sure the battery terminals are not loose or corroded. Check the fusible link for continuity.
  4.  
  5. Inspect the drive belt for excessive wear. Check the drive belt tension. If necessary adjust the drive belt.
  6.  
  7. Check the following fuses for continuity: ENGINE, CHARGE, IGN fuses.
  8.  
  9. Visually check alternator wiring and listen for abnormal noises.
  10.  
  11. Check that the discharge warning light comes ON when the ignition switch is turned ON. Start the engine. Check that the warning light goes out.
  12.  
  13. Check the charging circuit WITHOUT A LOAD. Connect a battery/alternator tester according to the manufacturer's instructions.
  14.  
  15. Check the charging circuit WITH A LOAD (turn on high beams and heater fan). Connect a battery/alternator tester according to the manufacturer's instructions.
  16.  
  17. Replace the necessary parts. Recheck the charging system. The standard amperage with a load on the system should be 30 amps. If a battery is fully charged, sometimes the indication will be less than 30 amps.
  18.  

REMOVAL & INSTALLATION



1985-90 Except 1990 VIN Code 5 Engine

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  


CAUTION
Failure to disconnect the battery can cause personal injury and damage to the car. If a tool is accidentally shorted at the alternator, it can become hot enough to cause a serious burn.

  1. Disconnect the large connector from the alternator.
  2.  
  3. Remove the nut and the single wire from the alternator.
  4.  
  5. Loosen the adjusting lock bolt (Prizm, lower bolt) and pivot (upper) bolt. Remove the drive belt.
  6.  

It may be necessary to remove other belts for access.

  1. Remove the lower bolt first, support the alternator and remove the upper pivot bolt. Remove the alternator from the car.
  2.  
  3. Installation is reverse of the above procedure. When reinstalling, remember to leave the bolts finger tight so that the belt may be adjusted.
  4.  
  5. Make sure that the plugs and connectors are properly seated and secure in their mounts.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Alternator mounting - 1985-88



Click image to see an enlarged view

Fig. Fig. 2: Alternator mounting - 1989-90 and 1991-92 base and LSi models

1991-92 All Engines and 1990 VIN Code 5 Engine

See Figures 2 and 3

  1. Disconnect the negative battery terminal from the battery.
  2.  

Failure to disconnect the negative cable may result in injury from the positive battery lead at the alternator and may short the alternator and regulator during the removal process.

  1. Remove the rubber protector, nut and wire from the battery B terminal on the alternator.
  2.  
  3. Remove the 3-wire alternator connector.
  4.  
  5. On the Prizm Base and LSi models use the following steps;
    1. Remove the upper and lower alternator bolts and nuts.
    2.  
    3. Remove generator.
    4.  

  6.  
  7. On the Prizm GSi models use the following steps;
    1. Raise and support the vehicle safely.
    2.  
    3. Remove the power steering and air conditioning drive belts.
    4.  
    5. Remove the lower mounting bolt and nut from the alternator bracket.
    6.  
    7. Remove the alternator drive belt from the pulley.
    8.  
    9. Remove the lower alternator mounting bracket (1 nut and 2 bolts).
    10.  
    11. Remove the alternator from the vehicle through the space between the right splash shield and the oil pan.
    12.  

  8.  

Removal of the alternator mounting bracket is necessary because of the extremely proximate nature of the engine compartment design. There is no way of getting the alternator out of the vehicle with the mounting bracket in place.

  1. Installation is reverse of the above procedure. When reinstalling, remember to leave the bolts finger tight so that the belt may be adjusted.
  2.  
  3. Make sure that the plugs and connectors are properly seated and secure in their mounts.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Alternator mounting - 1990-92 GSi models

1993

See Figure 4

  1. Disconnect the negative battery terminal from the battery.
  2.  

Failure to disconnect the negative cable may result in injury from the positive battery lead at the alternator and may short the alternator and regulator during the removal process.

  1. Loosen the pivot bolt and the adjusting lock bolt.
  2.  
  3. Remove the drive belt.
  4.  
  5. Remove the alternator connector from the back of the alternator.
  6.  
  7. Remove the 1 nut and alternator wire.
  8.  
  9. Remove the 2 clips and the wire harness.
  10.  
  11. Remove the 2 bolts and 1 nut, and remove the alternator from the mounting bracket.
  12.  

To install:
  1. Place the alternator in its brackets and install the mounting bolts. Do not tighten them yet.
  2.  
  3. Slip the belt back over the pulley. Pull outwards on the unit and adjust the belt tension. Tighten the mounting and adjusting bolts. Tighten the generator pivot mounting bolt to 26 ft. lbs. (35 Nm) and the adjusting lock bolt to 17 ft. lbs. (23 Nm).
  4.  
  5. Install the electrical leads and the negative battery cable.
  6.  



Click image to see an enlarged view

Fig. Fig. 4: Alternator mounting - 1993 all models

 
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