Home ReviewsRefund
Home/Mitsubishi/Lancer Evolution/Mitsubishi Lancer Evolution VIII (2003-2005)/Repair manual/Charging System/Generators & Regulators - Sportback
Contents Section: Charging System All sections

Generators & Regulators - Sportback Mitsubishi Lancer Evolution VIII

Charging System 20 illustrations ~2196 words

DESCRIPTION

Note. See appropriate SELF DIAGNOSTICS article in ENGINE PERFORMANCE to properly diagnose charging system.

The charging system charges the battery with the generator output to keep the battery charged at a constant level during varying electrical load.

OPERATION

Rotation of the excited field coil generates AC voltage in the stator. This alternating current is rectified through diodes to DC voltage having a waveform. The average output voltage fluctuates slightly with the generator load condition.

When the ignition switch is turned on, current flows in the field coil and initial excitation of the field coil occurs. When the stator coil begins to generate power after the engine is started, the field coil is excited by the output current of the stator coil. The generator output voltage rises as the field current increases and it falls as the field current decreases. When the battery positive voltage (generator S terminal voltage) reaches a regulated voltage of approximately 14.4V, the field current is cut off. When the battery positive voltage drops below the regulated voltage, the voltage regulator regulates the output voltage to a constant level by controlling the field current. In addition, when the field current is constant, the generator output voltage rises as the engine speed increases. (Scheme 22)

Scheme 22

Scheme 22: OPERATION
Scheme 22: OPERATION

BELT TENSION

For belt tension, see ADJUSTMENTS .

TROUBLE SHOOTING

  1. Is battery in good condition? If Yes, then go to next step. If No, then charge or replace battery.
  2. Is generator drive belt in good condition? If Yes, then go to next step. If No, then adjust belt tension or replace belt.
  3. Does the generator malfunction light come on when the ignition switch is turned on? If Yes, then go to next step. If No: Check the ignition switch. Check for burnt-out generator malfunction light. Check the generator. Check the generator malfunction light-related circuits.
  4. Does the generator malfunction light go out after starting the engine? If Yes, then go to next step. If No, check the generator.
  5. Is an oscilloscope available? If Yes, then go to next step. If No, then go to step 7 .
  6. Does the oscilloscope show a normal wave pattern? If Yes, then go to next step. If No, then check the generator.
  7. Turn the engine on and idle at 2500 RPM. Turn the headlights on with the High Beams on. Be sure that there is voltage between generator terminal B and the positive battery terminal of 0.5V or less. Check that the voltage between the negative battery terminal and generator body is 0.5V or less. Are the generator output line and ground line in good condition? If Yes, then go to next step. If No, check the generator output line and ground line.
  8. Is the output current normal? If Yes, then go to next step. If No, then check the generator.
  9. Is the regulated voltage normal? If Yes, then go to next step. If No, then check the generator.
  10. Is the voltage drop in the generator output line normal? If Yes, then generator is normal. Check other systems. If No, then check the output line.

GENERATOR OUTPUT LINE VOLTAGE DROP TEST

Required special tools: MB991958: Scan Tool MUT-III Sub Assembly, MB991824: V.C.I., MB991827: MUT-III USB Cable, MB991911: MUT-III Main Harness B.

This test determines whether the wiring from the generator B-terminal to positive battery terminal (including the fusible link) is in good condition or not. (Scheme 23)

Scheme 23

Scheme 23: GENERATOR OUTPUT LINE VOLTAGE DROP TEST
Scheme 23: GENERATOR OUTPUT LINE VOLTAGE DROP TEST
  1. Always be sure to check following before testing: Generator installation. Generator drive belt tension. Fusible link. Abnormal noise form generator while engine is running.
  2. Tune ignition switch to LOCK (OFF) position.
  3. Disconnect negative battery cable.
  4. Connect a clamp-type DC test ammeter with a range of 0-100A to the generator B terminal output wire.
  5. Connect a digital-type voltmeter between the generator B terminal and the positive battery terminal. (Connect the positive lead of the voltmeter to the B terminal, and then connect the negative lead of the voltmeter to the positive battery cable.)
  6. Reconnect the negative battery cable.
  7. Connect an engine tachometer or scan tool MB991958.
  8. Leave the hood open.
  9. Start the engine.
  10. With the engine running at 2500 RPM, turn the headlights and other lights on and off to adjust the generator load so that the value displayed on the ammeter is slightly above 30A. Read the voltmeter. Voltage reading at or below limit value means voltage drop between generator and batter is OK. There should be a maximum voltage of 0.3V.
  11. If the value displayed on the voltmeter is above the limit value, there is probably a malfunction in the generator output wire. Check the wiring between the generator B terminal and the positive battery terminal (including fusible link). If a terminal is not sufficiently tight or if the harness has become discolored due to overheating, repair and then test again.
  12. After the test, run the engine at idle.
  13. Turn off all lights and turn the ignition switch to the LOCK (OFF) position.
  14. Disconnect the engine tachometer or scan tool MB991958.
  15. Disconnect the negative battery cable.
  16. Disconnect the ammeter and voltmeter.
  17. Connect the generator output wire to the generator B terminal.
  18. Connect the negative battery cable.
  19. Run the engine for 10 minutes at an idle.

OUTPUT CURRENT TEST

Required special tool: MB991958: Scan Tool MUT-III Sub Assembly, MB991824: V.C.I., MB991827 MUT-III USB Cable, MB5991911: MUT-III Main Harness B. This test determines whether the generator outputs normal current. For best results, use a charging system tester. If not available, follow the steps below. (Scheme 24)

Scheme 24

Scheme 24: OUTPUT CURRENT TEST
Scheme 24: OUTPUT CURRENT TEST
  1. Before the test, always be sure to check the following. Generator installation. NOTE: The battery to be used should be slightly discharged. The load in a fully-charged battery will be insufficient and the test may not be able to be carried out correctly. Battery. Generator drive belt tension. Fusible link. Abnormal noise from the generator while the engine is running.
  2. Turn the ignition switch to the LOCK (OFF) position.
  3. Disconnect the negative battery cable.
  4. Connect a clamp-type DC test ammeter with a range of 0-100A to the generator B terminal output wire.
  5. Connect a voltmeter with a range of 0-20V between the generator B terminal and ground. (Connect the positive lead of the voltmeter to the B terminal, and then connect the negative lead of the voltmeter to ground.)
  6. Connect the negative battery cable.
  7. Connect an engine tachometer or scan tool MB991958.
  8. Leave the hood open.
  9. Check to be sure that the reading on the voltmeter is equal to the battery positive voltage.
  10. After turning on the headlights, start the engine.
  11. Immediately after setting the headlights to high beam and turning the heater blower switch to the highest position, increase the engine speed to 2,500 RPM and read the maximum current output value displayed on the ammeter. Limit value: 70 percent of nominal current output.
  12. The reading on the ammeter should be above the limit value. If the reading is below the limit value and the generator output wire is normal, remove the generator from the engine and check the generator.
  13. Run the engine at idle speed after the test.
  14. Turn the ignition switch to the LOCK (OFF) position.
  15. Disconnect the engine tachometer or scan tool MB991958.
  16. Disconnect the negative battery cable.
  17. Disconnect the ammeter and voltmeter.
  18. Connect the negative battery cable.
  19. Run the engine for 10 minutes at an idle.

REGULATED VOLTAGE TEST

Required special tools

  1. MB991958: Scan Tool MUT-III Sub Assembly.
  2. MB991824: V.C.I.
  3. MB991827: MUT-III USB Cable.
  4. MB991911: MUT-III Main Harness B.
  5. MB991519: Generator Harness Connector.

This test determines whether the voltage regulator is correctly controlling the generator output voltage. See

Scheme 25

Scheme 25
Scheme 25
  1. Always be sure to check the following before the test: Generator installation. Check to be sure that the battery installed in the vehicle is fully charged. Generator drive belt tension. Fusible link. Abnormal noise from the generator while the engine is running.
  2. Turn the ignition switch to the LOCK (OFF) position.
  3. Disconnect the negative battery cable.
  4. Use the special tool Generator Harness Connector: MB991519) to connect a digital-type voltmeter between the generator S terminal and ground. (Connect the positive lead of the voltmeter to the S terminal, and then connect the negative lead of the voltmeter to a secure ground or to the negative battery terminal.)
  5. Connect a camp-type DC test ammeter with a range of 0-100A to the generator B terminal output wire.
  6. Reconnect the negative battery cable.
  7. Connect an engine tachometer, or scan tool MB991958.
  8. Turn the ignition switch to the ON position and check that the reading on the voltmeter is equal to the battery positive voltage.
  9. Check to be sure that all lights and accessories are off.
  10. Start the engine.
  11. Increase the engine speed to 2,500 RPM
  12. Read the value displayed on the voltmeter when the current output by the generator becomes 10A or less.
  13. If the voltage reading conforms to the value in the voltage regulation table, then the voltage regulator is operating normally. If the voltage is outside the standard value, there is a malfunction of the voltage regulator or the generator. See «REGULATOR VOLTAGE SPECIFICATIONS TABLE»(/mitsubishi/lancer-evolution/viii-2003-2005/remont/charging-system/#generators-regulators-sportback) .
  14. After the test, lower the engine speed to idle.
  15. Turn the ignition switch to the LOCK (OFF) position.
  16. Disconnect the engine tachometer or scan tool MB991958.
  17. Disconnect the negative battery cable.
  18. Disconnect the ammeter and voltmeter.
  19. Connect the negative battery cable.
  20. Run the engine for 10 minutes at an idle.
Ambient Temp. °F (°C)Voltage
Terminal S
4 (-20)14.2-15.4
68 (20)13.9-14.9
140 (60)13.4-14.5
176 (80)13.1-14.2

REGULATOR VOLTAGE SPECIFICATIONS

Abnormal Waveforms

The size of the waveform patterns can differ greatly, depending on the adjustment of the variable knob on the oscilloscope. (Scheme 26)

Identification of abnormal waveforms is easier when there is a large output current (regulator is not operating). Waveforms can be observed when the headlights are illuminated.

Check the conditions of the generator malfunction light (illuminated/not illuminated) also, and carry out a total check.

Scheme 26

Scheme 26: Abnormal Waveforms
Scheme 26: Abnormal Waveforms

Measurement Method

Connect the oscilloscope special patterns pick-up to the generator B terminal. (Scheme 27)

Scheme 27

Scheme 27: Measurement Method
Scheme 27: Measurement Method

Standard Waveform

Note. The voltage waveform of the generator B terminal can undulate. This waveform is produced when the regulator operates according to fluctuations in the generator load (current), and is normal for the generator. If the ripple height is abnormally high (approximately 2V or more during idling), the wires between the generator B terminal and the battery have broken due to fuse blowing, etc. The generator is usually operating properly.

For standard waveform observation conditions (Scheme 28)

Scheme 28

Scheme 28: Standard Waveform
Scheme 28: Standard Waveform

BRUSH

  1. Replace the brush is the brush protrusion length is below 0.08" (2 mm). (Scheme 29)
  2. The brush can be removed by unsoldering the brush lead wire. (Scheme 30)
  3. When installing a new brush, push the brush in to the brush holder, and solder the lead wire.

Scheme 29

Scheme 29
Scheme 29

Scheme 30

Scheme 30
Scheme 30

ROTOR

  1. Check the continuity between the slip rings of the field coil. If the resistance value is not within 2-5ohm, replace the rotor. (Scheme 31)
  2. Check the continuity between the slip ring and the core. If there is continuity, replace the rotor. (Scheme 32)

Scheme 31

Scheme 31
Scheme 31

Scheme 32

Scheme 32
Scheme 32

RECTIFIER

  1. Check the continuity between the positive rectifier and the stator coil lead connection terminal with a tester. If there is continuity between the terminals, the diode is shorted, so replace the rectifier. (Scheme 33)
  2. Check the continuity between the negative rectifier and the stator coil lead connection terminal with a tester. If there is continuity between the terminals, the diode is grounded, so replace the rectifier. (Scheme 34)
  3. Check the continuity of the 3 diodes by connecting an ohmmeter to both ends of each diode. If there is continuity between the directions, or if there is no continuity, the diode is damaged, so replace the rectifier. (Scheme 35)

Scheme 33

Scheme 33
Scheme 33

Scheme 34

Scheme 34
Scheme 34

Scheme 35

Scheme 35
Scheme 35

STATOR

  1. Check the continuity between the coil lead. If there is no continuity, replace the stator. (Scheme 36)
  2. Check the continuity between the coil and the core. If there is continuity replace the stator. (Scheme 36)

Scheme 36

Scheme 36
Scheme 36

For generator removal and installation procedures (Scheme 37)

Scheme 37

Scheme 37: GENERATOR
Scheme 37: GENERATOR

Removal Service Points

  1. A) Generator Removal - Remove the generator from the vehicle.

For disassembly procedures (Scheme 38)

Scheme 38

Scheme 38: GENERATOR
Scheme 38: GENERATOR

Disassembly Service Points

  1. A) Front Bracket Assembly Removal - Insert a flat-tipped screwdriver between the front bracket assembly and the stator core, and pry it downward to separate the stator and front bracket assembly. (Scheme 39)
  2. B) Generator Pulley Removal - Set the pulley upward, clamp the rotor in a vise, and remove the pulley.
  3. C) Stator Removal - Using a soldering iron (180-250W) to unsolder the stator. This work should complete within approximately 4 seconds to prevent heat from transferring to the diode. When removing the rectifier from the regulator assembly, unsolder the points soldered on the rectifier. (Scheme 40)

Scheme 39

Scheme 39
Scheme 39

Scheme 40

Scheme 40
Scheme 40

Assembly Service Points

  1. A) Regulator Assembly Installation - After installing the regulator assembly, insert a wire through the hold provided on the rear bracket while pressing down on the brush, and secure the brush. (Scheme 41)
  2. B) Rotor Assembly Installation - After installing the rotor, remove the wire used to secure the brush.

Scheme 41

Scheme 41
Scheme 41

TORQUE SPECIFICATIONS

See illustration under REMOVAL & INSTALLATION or OVERHAUL .

WIRING DIAGRAMS

For wiring diagrams, see STARTING/CHARGING .

More articles — Electrical