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Mitsubishi Montero (1991+). Manual - part 40

terminal "B" and negative lead to positive battery terminal. Reconnect

negative battery cable.

3) Start engine. Turn accessories on and adjust engine speed

until ammeter indicates 20 amps, and note voltmeter reading. If

voltmeter indicates .2 volt or less, system is okay.

4) If voltage is greater than .2 volt, wiring is defective

between alternator terminal "B", fusible link and battery positive

terminal. Disconnect negative battery cable, and remove test

equipment.

ALTERNATOR OUTPUT TEST

NOTE: During alternator output test, a slightly discharged battery

should be used as a fully charged battery may not allow full

alternator output.

1) Turn ignition switch to OFF position. Disconnect negative

battery cable. Disconnect alternator output wire from terminal "B".

Install positive lead of 100-amp ammeter to terminal "B" and negative

lead to disconnected output lead.

CAUTION: Tighten each connection securely as heavy current flow will

exist. DO NOT use clips on ammeter.

2) Connect positive voltmeter lead (0-20 volts) to alternator

terminal "B" and negative lead to ground. Install tachometer, and

reconnect negative battery cable.

3) Ensure voltmeter indicates battery voltage. If no voltage

exists, an open circuit is present in wire between alternator terminal

"B" and battery negative terminal. Check grounds and fusible link.

4) Turn headlights on, and start engine. Set headlights at

high beam and heater switch on HIGH. Quickly accelerate engine speed

to 2500 RPM and note alternator output current registered on the

ammeter. Minimum output should be within specification. Refer to the

ALTERNATOR MINIMUM OUTPUT SPECIFICATIONS table.

NOTE: Output voltage changes with electrical load and temperature.

Ensure proper electrical load is applied while checking

output. Nominal output may not be obtained if alternator or

ambient temperature is excessive. Allow to cool, and recheck

output. Alternator output is stamped on metal plate attached

to alternator case.

5) If minimum output is not obtained and alternator wiring is

okay, repair alternator. Disconnect negative battery cable, and remove

test equipment.

REGULATED VOLTAGE TEST

NOTE: Ensure battery is fully charged and proper drive belt

tension exists.

1) Turn ignition switch to OFF position. Disconnect negative

battery cable. Install a digital voltmeter between alternator terminal

"S" and ground. See Fig. 10. Connect positive voltmeter lead to

terminal "S" of alternator. Connect negative voltmeter lead to ground.

2) Disconnect alternator output wire from terminal "B".

Install a 100-amp ammeter in series to terminal "B" and disconnected

output lead. Install positive lead of ammeter to terminal "B" and

negative lead to disconnected output wire. Install a tachometer, and

reconnect negative battery cable.

3) Turn ignition switch to ON position and ensure voltmeter

indicates battery voltage. If no voltage exists, an open circuit

exists in wire between alternator terminal "S" and positive battery

terminal or fusible link is blown.

4) Start engine. Ensure all lights and accessories are off.

Operate engine at 2500 RPM and read voltmeter when alternator output

current drops to 10 amps or less. Voltage regulator is okay if voltage

output is within specification. See REGULATOR VOLTAGE SPECIFICATIONS

table.

BENCH TESTING

RECTIFIER ASSEMBLY

1) Using ohmmeter, check for continuity between both diodes

and stator coil lead connection. See Fig. 11. Reverse leads. If

continuity exists in both directions, diode is shorted. Replace

rectifier assembly.

2) To check entire diode assembly, use an ohmmeter to check

for continuity between both ends of each diode. See Fig. 11. Switch

ohmmeter leads. Continuity should exist in one direction, but not

other. If no continuity exists or continuity exists in both

directions, diode is defective. Replace rectifier assembly.

Fig. 11: Testing Rectifier Assembly

Courtesy of Mitsubishi Motor Sales of America.

ROTOR

1) Check continuity across rotor slip rings. Resistance

should be within specification. See ROTOR RESISTANCE SPECIFICATIONS

table. Replace rotor if no continuity exists or resistance is not

within specification.

2) Check continuity between individual slip rings and rotor

shaft. If continuity exists, rotor coil or slip ring is grounded.

Replace rotor.

STATOR

Ensure no continuity exists between stator coil leads and

stator core. Check continuity between leads of stator coil. If no

continuity exists between coil leads, replace stator.

OVERHAUL

Replace brushes if worn to limit line. Limit line is line

closest to rotor contact end of brush. Brushes can be retained in

brush holder while installing rotor by inserting wire into back of

rear housing.

Fig. 12: Exploded View of Typical Mitsubishi Alternator

Courtesy of Mitsubishi Motor Sales of America.

SPECIFICATIONS

ALTERNATOR MINIMUM OUTPUT SPECIFICATIONS TABLE

Application Amps

Colt, Colt 200, Galant, Montero, Precis & Summit ......... 52.5

Colt Vista ................................................. 45

Eclipse

A/T & M/T Turbo ........................................ 52.5

M/T Non-Turbo .......................................... 45.5

Mirage

1.5L & 1.6L A/T ........................................ 52.5

1.6L M/T ............................................... 45.5

Pickup & Ram-50

2.4L ..................................................... 28

2.4L (Optional - Ram-50) ................................. 42

3.0L ................................................... 45.5

Stealth & 3000GT

DOHC ..................................................... 77

SOHC ..................................................... 63

REGULATOR VOLTAGE SPECIFICATIONS TABLE

Ambient Temperature Voltage

-4

F (-20

C) ........................................ 14.2-15.4

F (20

C) ......................................... 13.9-14.9

140

F (60

C) ........................................ 13.4-14.6

176

F (80

C) ........................................ 13.1-14.5

ROTOR RESISTANCE SPECIFICATIONS TABLE

Application Ohms

Colt, Colt 200, Mirage, Precis & Summit ................... 3.1

Colt Vista ................................................ 4.3

Eclipse, Galant, Montero, Pickup,

Ram-50, Stealth & 3000GT ............................. 3.0-5.0

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