Mitsubishi Eclipse 1990-1998 Repair Guide

Alternator

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TESTING



Alternator Output Wire Voltage Drop

See Figure 1

This test will determine whether or not the wiring (including the fusible link) between the alternator B terminal and the battery positive terminal is sound by voltage drop method. A clamp type ammeter that can measure current without disconnecting the harness is preferred for this test.

TEST PREPARATION
  1. Turn the ignition OFF .
  2.  



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Fig. Fig. 1: Schematic of the alternator output wire voltage drop test

  1. Disconnect the battery ground cable.
  2.  
  3. Disconnect the alternator output lead from the alternator B terminal.
  4.  
  5. Connect the positive lead of an ammeter to the B terminal and the negative lead to the disconnected output wire.
  6.  
  7. Connect a digital voltmeter between the alternator B terminal and the battery positive terminal. Connect the positive lead wire of the voltmeter to the B terminal and the negative lead wire to the battery positive terminal.
  8.  
  9. Connect the battery ground cable.
  10.  
  11. Leave the hood to the engine compartment open.
  12.  

TEST PROCEDURE
  1. Start the engine.
  2.  
  3. Turn the headlamps and small lamps ON and adjust the engine speed so that the ammeter reads 20A. Note the voltmeter indication under this condition.
  4.  
  5. It is OK if the voltmeter reads the standard value of 0.2V max.
  6.  
  7. If the voltmeter indicates a value larger than the standard value, poor wiring is suspected, in which case check the wiring from the alternator B terminal to the fuse link to battery positive terminal. Check for loose connection, color change due to overheating hardness, etc. and correct before testing again.
  8.  
  9. Upon completion of the test, set the engine speed at idle.
  10.  
  11. Turn the lights and the ignition switch OFF .
  12.  
  13. Disconnect the battery ground cable.
  14.  
  15. Disconnect the ammeter and the voltmeter that have been connected for the purpose of the test.
  16.  
  17. Connect the alternator output wire to the alternator B terminal.
  18.  
  19. Connect the battery ground cable.
  20.  

Alternator Output Current Test

See Figure 2

This test is designed to judge whether or not the alternator gives an output current that is equivalent to the nominal output.

TEST PREPARATION
  1. Check the battery that installed in the vehicle, making sure it is in good sound state. Test the battery as required to assure this. The battery used to check output current should be one that has been rather discharged. With a fully discharged battery, the test may not be conducted correctly due to an insufficient load.
  2.  
  3. Check the alternator drive belt for proper tension, as outlined in General Information & Maintenance .
  4.  
  5. Make sure the ignition switch is turned OFF . Disconnect the battery ground cable.
  6.  
  7. Disconnect the alternator output lead from the alternator B terminal.
  8.  
  9. Connect the positive lead of an ammeter to the B terminal and the negative lead to the disconnected output wire.
  10.  



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Fig. Fig. 2: Test the alternator output current as shown

Tighten each connection by bolt and nuts securely as a heavy current will flow through the wire. Do not rely on clips.

  1. Connect a voltmeter between the B terminal and ground. Connect the positive lead wire to the alternator B terminal and the negative lead wire to a sound ground.
  2.  
  3. Connect the battery ground cable.
  4.  
  5. Leave the hood open.
  6.  

TEST PROCEDURE
  1. Check to see that the voltmeter reads the same value as the battery voltage. If the voltmeter reads 0 volts, an open circuit in the wire between the alternator B terminal and the battery negative terminal, a blown fuse link, or poor grounding is suspected.
  2.  
  3. Turn the headlight switch on and start the engine.
  4.  
  5. Set the headlights at high beam and the heater blower switch at high, quickly increase the engine speed to 2,500 rpm and read the maximum output current value indicated by the ammeter.
  6.  

After engine start up, the charging current drops quickly, therefore, above operation must be done quickly to read the maximum current value correctly.

  1. The ammeter reading must be higher than the limit value. If it is lower than the limit value but the alternator output wire is normal, remove the alternator from the vehicle and check it further. The limit values are as follows:

    65A alternator-45.5A minimum
     
    75A alternator-52.5A minimum
     

  2.  

The nominal output current value is shown on the nameplate affixed to the alternator body. The output current value changes with the electrical load and the temperature of the alternator itself. Therefore, the nominal output current may not be obtained if the vehicle electrical load at the time of the test is small. In such case, keep the headlights on to cause discharge of the battery to increase the electrical load. The nominal output current may not be obtained if the temperature of the alternator itself or ambient temperature is too high.

  1. Upon completion of the test, lower the engine speed to idle and turn the ignition switch OFF .
  2.  
  3. Disconnect the battery ground cable.
  4.  
  5. Disconnect and remove the engine tachometer, voltmeter and ammeter connected for the purpose of this test.
  6.  
  7. Connect the alternator output wire.
  8.  
  9. Connect the battery ground cable.
  10.  

Regulated Voltage Test

See Figure 3

The purpose of this test is to determine that the electronic voltage regulator controls the voltage correctly.

TEST PREPARATION
  1. Check the battery that installed in the vehicle, making sure it is in good sound state. Test the battery as required to assure this. The battery must be fully charged.
  2.  
  3. Check the alternator drive belt for proper tension as outlined in General Information & Maintenance .
  4.  
  5. Make sure the ignition switch is turned OFF . Disconnect the battery ground cable.
  6.  
  7. Connect a digital voltmeter between the S terminal of the alternator and the alternator. inserting from the wire side of the 2-way connector. Connect the negative test lead to a sound ground or negative battery terminal.
  8.  
  9. Disconnect the alternator output lead from the alternator B terminal.
  10.  
  11. Connect the positive lead of an ammeter to the B terminal and the negative lead to the disconnected output wire.
  12.  
  13. Connect the battery ground cable.
  14.  
  15. Leave the hood open.
  16.  

TEST PROCEDURE
  1. Turn the ignition switch ON . Check to see that the voltmeter reads the same value as the battery voltage. If the voltmeter reads 0 volts, an open circuit in the wire between the alternator S terminal and the battery positive terminal or the fuse link is blown.
  2.  
  3. Start the engine and keep all lights and accessories off.
  4.  
  5. Run the engine at 2,500 rpm and read the voltmeter when the alternator output current drops to 10A or less.
  6.  



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Fig. Fig. 3: Regulated voltage test component positioning

  1. If the voltmeter readings agree with the desired readings listed below, the voltage regulator is functioning properly. If the measured reading disagrees with the desired value, the voltage regulator or the alternator is faulty. The desired voltages are as follows:
  2.  



Voltage regulator ambient temperature at 68°F (20°C)-13.9-14.9 volts
 
Voltage regulator ambient temperature at 140°F (68°C)-13.4-14.6 volts
 
Voltage regulator ambient temperature at 176°F (80°C)-13.1-14.5 volts
 

  1. Upon completion of test, set the engine speed at idle and turn the ignition switch OFF .
  2.  
  3. Disconnect the negative battery terminal.
  4.  
  5. Disconnect all test meters installed for this test procedure.
  6.  
  7. Connect the alternator output wire to the alternator B terminal.
  8.  
  9. Connect the negative battery terminal.
  10.  

REMOVAL & INSTALLATION



1990-94 Vehicles

See Figure 4

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle. Remove the left wheel and tire assembly.
  4.  
  5. For 2.0L engines, remove the left side undercover from the vehicle.
  6.  
  7. If equipped with A/C, remove the condenser electric fan motor and shroud assembly.
  8.  
  9. Remove the alternator, water pump and air conditioner compressor drive belts.
  10.  
  11. Remove both of the water pump pulleys.
  12.  
  13. Remove the alternator top brace.
  14.  
  15. Disconnect the alternator wiring, then remove the alternator from the vehicle.
  16.  



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of the alternator and related components-1990-94 1.8L and 2.0L engines

To install:
  1. Manuever the alternator into position, then connect the electrical harness.
  2.  
  3. Install the alternator top brace to the engine and tighten the mounting bolt to 20 ft. lbs. (27 Nm).
  4.  
  5. Install the alternator mounting bolt loosely.
  6.  
  7. Install the water pump pulleys and tighten retainer bolts to 7 ft. lbs. (10 Nm).
  8.  
  9. Install the drive belts and adjust until the proper tension is achieved. Secure the lower alternator through-bolt nut to 18 ft. lbs. (25 Nm) and the upper alternator lock bolt to 11 ft. lbs. (15 Nm).
  10.  
  11. Install the condenser electric fan motor and shroud assembly.
  12.  
  13. Install the left side undercover from the vehicle, if removed.
  14.  
  15. Connect the negative battery cable. Start the engine and check the alternator for proper operation.
  16.  

1995-98 Vehicles
2.0L NON-TURBO ENGINE

See Figures 5, 6, 7, 8, 9 and 10

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the left side wheel and tire assembly. Remove the under cover side panel.
  6.  
  7. For 2.0L non-turbo engines equipped with auto-cruise control, remove the speed control assembly.
  8.  
  9. Remove the alternator drive belt, as outlined in General Information & Maintenance of this repair guide.
  10.  



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Fig. Fig. 5: Exploded view of the alternator mounting-1995-98 2.0L non-turbo engine

  1. Detach the alternator harness connector(s).
  2.  



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Fig. Fig. 6: There are two electrical connections found on the back of the alternator



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Fig. Fig. 7: With the vehicle raised and supported, unplug the electrical connector from the rear of the alternator



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Fig. Fig. 8: Unfasten the BAT terminal retaining nut from the rear of the alternator

  1. Remove the lower alternator bracket.
  2.  



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Fig. Fig. 9: Remove the alternator adjusting bolt

  1. Remove the alternator adjusting bolt.
  2.  
  3. Remove the mounting bolts, then remove the alternator from the vehicle.
  4.  



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Fig. Fig. 10: Remove the alternator mounting bolts, then carefully lower the alternator and remove it from vehicle

To install:
  1. Install the alternator brace and secure with the retainers.
  2.  
  3. Position the alternator and bracket.
  4.  
  5. Attach the alternator harness connectors.
  6.  
  7. Install the alternator drive belt. Adjust the tension as outlined in General Information & Maintenance of this repair guide.
  8.  
  9. Install the under cover side panel and the wheel and tire assembly.
  10.  
  11. Carefully lower the vehicle, then connect the negative battery cable.
  12.  

2.0L TURBO AND 2.4L ENGINES

See Figures 11, 12, 13 and 14

  1. Disconnect the negative battery cable.
  2.  
  3. If necessary, partially raise and support the vehicle.
  4.  
  5. Remove the left side wheel and tire assembly. Remove the under cover side panel.
  6.  
  7. Remove the alternator drive belt.
  8.  
  9. Unplug the alternator harness connector(s).
  10.  
  11. For the 2.0L turbo engine, perform the following:
  12.  

Do NOT disconnect the oil pump hose.

    1. Remove the mounting bolt of the power steering oil pump, and hold the pump above the engine mount bracket. Use a rag to prevent scratching of the rocker cover.
    2.  




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Fig. Fig. 11: Exploded view of the alternator and related components



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Fig. Fig. 12: Position the power steering pump aside with a rag underneath

    1. With the alternator facing as shown in the accompanying figure, lift upward and remove the alternator from the vehicle.
    2.  




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Fig. Fig. 13: On the 2.0L engine, lift the alternator up and out of the vehicle

  1. For the 2.4L engine, perform the following:
    1. Remove the oil pressure switch terminal.
    2.  

  2.  



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Fig. Fig. 14: On the 2.4L engine, you must remove the oil pressure switch terminal for room to remove the alternator

    1. Remove the alternator from the underside of the vehicle.
    2.  


  1. If necessary to remove the alternator brace, perform the following:
    1. Remove the power steering drive belt.
    2.  
    3. Remove the water pump pulley.
    4.  
    5. Remove the power steering pump pulley.
    6.  
    7. Remove the alternator brace from the vehicle.
    8.  

  2.  

To install:
  1. Installation is the reverse of the removal.
  2.  
  3. Note that the alternator is installed from the top of the engine for the 2.0L turbo engine and from underneath the vehicle on the 2.4L engine.
  4.  
  5. During installation, make sure to tighten all retainers to the specifications shown in the accompanying figures.
  6.  
  7. Install the undercover side panel, then carefully lower the vehicle.
  8.  
  9. Connect the negative battery cable.
  10.  

 
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