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Alternator & Regulator BMW M3 E36

Charging System 3 illustrations ~714 words

IDENTIFICATION

ApplicationCapacity
All Models80 Amps

GENERATOR APPLICATIONS

DESCRIPTION

Bosch conventional 3-phase, self-rectifying type generators use 3 exciter diodes connected to stator windings. These diodes turn off generator indicator light and supply power to voltage regulator while engine is running. Bosch regulators are transistorized and integral with generator.

Wiring Continuity Test

  1. Connect voltmeter between generator B+ terminal and ground. Voltmeter should indicate battery voltage. If battery voltage is not indicated, check wiring between generator and battery.
  2. Turn ignition on and ensure generator indicator light comes on. If light does not come on, check indicator light bulb, and wiring between generator and warning light.

Output Test

  1. Ensure connections at battery, generator, and starter (most vehicles) are clean and tight. Ensure generator, engine and body are properly grounded.
  2. Ensure generator drive belt is tight and in good condition. Connect charging system tester according to manufacturer's instructions. Connect voltmeter leads to battery terminals.
  3. Start and operate engine at 3000 RPM. Adjust carbon pile on tester to obtain maximum generator output. DO NOT allow voltage to drop to less than 12.6 volts.
  4. Generator output should equal generator rated output. If reading is 16-20 amps less than generator rating, replace regulator and retest. If output is still low, repair or replace generator.

Regulator Control Voltage Test

  1. Connect charging system tester according to manufacturer's instructions. Connect voltmeter leads to battery terminals. Start and operate engine at 3000 RPM.
  2. Operate engine until voltage stops rising. Voltage should be 13.5-14.2 volts. If reading is incorrect, remove regulator and ensure brushes are longer than 0.198" (5.0 mm). Replace if necessary.
  3. If brushes are okay and regulator fails to keep voltage within specified limits, replace regulator and retest. If voltage is still incorrect, repair or replace generator.

Diode Assembly

  1. Place ohmmeter on X100 scale. Connect ohmmeter leads, in turn, between B+ terminal and each of the 3 stator terminals. (Scheme 1) Reverse leads. Ohmmeter should indicate continuity in one direction only.
  2. Connect ohmmeter leads, in turn, between negative plate and each of the 3 stator terminals. Reverse leads. Ohmmeter should indicate continuity in one direction only.
  3. Connect ohmmeter leads, in turn, between D+ terminal and each of the 3 stator terminals. Reverse leads. Ohmmeter should indicate continuity in one direction only. Replace diode assembly if continuity is not as specified.

Scheme 1

Scheme 1
Scheme 1

Stator

  1. Place ohmmeter on lowest scale. Measure resistance between 2 of the 3 sets of wires. Move one ohmmeter lead to the other set of wires. Check resistance between the remaining set of wires. Resistance values must be identical. If resistance is incorrect, stator has open or shorted windings and must be replaced.
  2. Place ohmmeter on X1000 scale. Connect ohmmeter between stator core and each stator lead. Continuity should not exist. If continuity exists, stator is grounded and must be replaced.

Rotor

  1. Place ohmmeter on lowest scale. Connect ohmmeter across slip rings. Ensure resistance is within specification. See the «ROTOR RESISTANCE»(/bmw/m3/e36-1992-1999/remont/charging-system/#alternator-regulator) table.
  2. If resistance is too low, rotor has short circuit and must be replaced. If resistance is infinite (no continuity), rotor has open circuit and must be replaced.
  3. Place ohmmeter on X1000 scale. Connect ohmmeter between rotor core and either slip ring. Continuity should not exist. If continuity exists, rotor is grounded and must be replaced.
ApplicationOhms
80-Amp Generator2.6-3.2

ROTOR RESISTANCE

TROUBLE SHOOTING

Note. See the TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL INFORMATION section.

Removal

  1. Install memory saver (computer, radio, etc.) and disconnect battery. Remove air filter housing. Using Pulley Holder (11-5-030 ) and 32-mm Wrench (11-5-040 ), turn cooling fan nut clockwise (left-hand thread) to remove cooling fan.
  2. Note serpentine belt routing. Insert socket into drive belt tensioner bolt. Compress tensioner slowly and remove belt.
  3. Remove mounting bolts and cooling duct (if equipped). Remove wiring and generator.

Installation

To install, reverse removal procedure. Ensure serpentine belt is correctly routed and seated in grooves. Use Pulley Holder (11-5-030 ) to hold water pump pulley, and turn 32-mm Wrench (11-5-040 ) counterclockwise (left-hand thread) to tighten cooling fan nut to 22 ft. lbs. (30 N.m).

Note. Tighten cooling fan nut to 29 ft. lbs. (40 N.m) if a conventional 32-mm open end wrench is used.

OVERHAUL

For overhaul procedures (Scheme 2)for exploded view of generator.

Scheme 2

Scheme 2: OVERHAUL
Scheme 2: OVERHAUL

Charging System Wiring Diagram. Scheme 3

Scheme 3: Charging System Wiring Diagram
Scheme 3: Charging System Wiring Diagram