2007 ISUZU KB P190 engine

Charging System – V6 Page 6D1-1-3

1 General Information
1.1 Components
Generator
The Mitsubishi generator can be identified visually by its two lower and one upper mounting lugs.
It is mounted to the lower right-hand side of the engine block. It is driven by the same drive belt that drives other engine
ancillaries and requires no periodic drive belt adjustment.
The generator has three phases, incorporating a rotor with six pole pairs fitted and two internal cooling fans; one on the
drive-end and one on the slip-ring end. The rotor is supported by ball bearings in both the drive and slip-ring end
housings. Surrounding the rotor is a stator, which has a three phase delta connected output winding construction on a
ring shaped lamination pack.
The output of the stator winding is rectified by eight diodes that are contained within the slip-ring end housing. Excitation
current is supplied to the rotor field coil via the voltage regulator, the brushes and slip-rings. The electronic voltage
regulator requires no adjustment in service.
The generator has four external connections (refer to Figure 6D1-1 1):
• Generator – Terminal P-9 to the battery positive terminal P-1 via fuse SBF1,
• Generator – E-4 pin 1 to the ECM connection E-60 pin 43 – regulator monitoring,
• Generator – E-4 pin 2 to the ECM connection E60 pin 21 – battery voltage sensing, and
• ground connection via the installation bolts.
Generator Types
The vehicle is fitted with a 120 amp generator.


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Charging System – V6 Page 6D1-1-5

• Death or injury to other people in or near the workplace area, and / or
• Death or injury to the driver / or passenger(s) of the vehicle or other people, if the vehicle has been improperly
repaired.
CAUTION defined
A CAUTION statement immediately precedes an operating procedure or maintenance practice which, if not correctly
followed, could result in damage to or destruction of equipment, or corruption of data. If a CAUTION statement is
ignored, the following consequences may occur:
• Damage to the vehicle,
• Unnecessary vehicle repairs or component replacement,
• Faulty operation or performance of any system or component being repaired,
• Damage to any system or components which depend on the proper operation of the system or component being
repaired,
• Faulty operation or performance of any systems or components which depend on the proper operation or
performance of the system or component under repair,
• Damage to fasteners, basic tools or special tools and / or
• Leakage of coolant, lubricant or other vital fluids.
NOTE defined
A NOTE statement immediately precedes or follows an operating procedure, maintenance practice or condition that
requires highlighting. A NOTE statement also emphasises necessary characteristics of a diagnostic or repair procedure.
A NOTE statement is designed to:
• Clarify a procedure,
• Present additional information for accomplishing a procedure,
• Give insight into the reasons for performing a procedure in the recommended manner, and / or
• Present information that gives the technician the benefit of past experience in accomplishing a procedure with
greater ease.

1.3 System Operation
Operation
W ith the ignition switch in the ON position and the engine at rest, current is supplied via the regulator to generator
connector E-4 pin 1 and to the engine control module ECM connector E-60 pin 43. This initiates current flow (within the
regulator) from the generator connection P-9, to the brushes and rotor winding, to ‘excite’ the circuit.
The current in the rotor winding creates magnetic fields between adjacent rotor poles.
W ith the engine running, the rotor spins, the stator windings cut through this field and induce voltage. As the engine
speed is increased, this induced voltage increases. Current then flows through the three-phase diode bridge in the
rectifier to convert the AC voltage to DC. This is supplied to the generator connector P-9 output and then to the battery
terminal via fuse SBF1.
The regulator monitors the voltage to the battery. W hen this voltage reaches approximately 14.5 V, the regulator opens
the circuit through the rotor winding, causing the generator output voltage to drop. W hen the regulator senses a voltage
below a preset voltage, the regulator closes the circuit through the rotor winding and voltage to the battery again
increases. This cycle repeats very rapidly.

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2 Diagnosis
2.1 Diagnostic General Information
Basic Diagnostic Tools Required

Use of incorrect electrical circuit diagnostic
tools when performing the generator
diagnostic procedures could result in
incorrect diagnostic results or damage to
components.
The following electrical circuit testing tools are required to perform the diagnostic procedures detailed in this Section:
• digital multimeter with 10 mega ohms impedance, and
• connector test adapter kit Tool No. KM609.
For further information on the use of these tools, refer to 8A Electrical Body and Chassis.
2.2 Tech 2 Data List
The Tech 2 displays the status of certain charging system parameters.
To view the data list:
1 Connect Tech 2 to the DLC.
2 On Tech 2 select: Engine / V6 Engine / Data Display / Data List / Electrical/Theft Data .
Tech 2 Parameter Units Displayed Typical Display Values
Alternator L Terminal D Percentage Various
2.3 Diagnostic Systems Check
Step Action Yes No
1 1 Connect Tech 2 to the DLC.
2 Ignition ON, engine OFF.
3 On Tech 2 select: Engine / V6 Engine / Diagnostic Trouble codes / Read
DTC’s.
Are there any set DTC’s? Go to the
appropriate DTC table in 6C1-2 Engine
Management – V6 – Diagnostics. Refer to 2.5
Charging
System Inoperative / Malfunctioning

Reference to following information will assist when diagnosing charging circuit faults:
• for battery testing, refer to 6D1-3 Battery – V6,
• for wiring diagram details, refer to Figure 6D1-1 2, and
• for electrical component locations, refer to 8A Electrical Body and Chassis.

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3 Minor Service Operations
3.1 Safety Precautions
Observe the following precautions. Failure to observe these precautions will result in serious damage to the generator.
• Only use the generator and voltage regulator in a negative ground system.
• Always refer to 1.2 W ARNING, CAUTION and NOTES before disconnecting the battery.
• W hen installing a battery, fit the positive (+) cable to the battery before fitting the negative cable.
• W hen a slave battery is used for starting purposes, ensure that both batteries are connected in parallel. That is,
positive terminals connected and negative terminals connected.
• Only use jumper leads that have surge protection.
• Disconnect both battery cables when charging the battery. This isolates the generator from the battery and from
the external charging equipment.
• Do not operate the generator within an open circuit or without a battery in the circuit.
• Do not disconnect the battery while the generator is running.
• Do not attempt to polarise the generator.
• Do not connect generator connector E-4 pin 1 to 12 V (the battery or ignition circuits).
• Some battery powered timing lights can produce high transient voltages when connected or disconnected.
Only disconnect or connect timing lights when the engine is switched off.

Ensure the generator connector E-4 pin 1 has
a maximum sinking current of 50mA.
3.2 Maintenance
Regular Checks
Check the following at regular intervals:
• generator terminals – for corrosion and loose connections,
• wiring – for continuity and damaged insulation,
• mounting bolts – for tightness,
• drive belt – for alignment and wear, and
• drive pulley – for damage and warping.
NOTE
The drive-belt adjustment for the engine
ancillaries (i.e. generator and water pump) is
provided by a spring-loaded tensioner. Therefore,
the drive belt does not require manual
adjustment.
Lubrication
High tolerance bearings are used in this generator. If the bearings are removed during the generator disassembly, new
bearings must be installed to restore the generator to original specification. The ball bearings supporting the rotor shaft
are pre-lubricated and sealed. Do not attempt to lubricate these during servicing.

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3.3 On-vehicle Testing
Generator On-vehicle Checks
Prerequisites
Before testing the generator output, ensure that:
• all generator circuit connections are clean and tight,
• the generator is always connected to the battery during testing (to prevent damage to the diodes),
• the battery is fully charged, and
• the specific gravity does not vary more than 0.025 between cells. (It is recommended the average specific gravity
is 1.260 or higher). Refer to 6D1-3 Battery – V6.
Carry out a load test on the battery to determine its ability to supply and accept current. This is a good indicator of the
general condition of the battery. For details of battery testing, refer to 6D1-3 Battery – V6.
Inspect the drive belt and tensioner markings to determine if the drive belt is within operating limits. Replace the belt if it
is excessively worn or outside the operating range of the tensioner.
For further details, refer to 6A1 Engine Mechanical – V6.
Generator Test
Regulating Voltage Test
NOTE
Leave the generator E-4 wiring harness
connector connected, as it provides initial field
excitation.
1 Ensure the ignition switch is in the OFF position and all electrical equipment is turned off.

Refer to 1.2 WARNING, CAUTION and
NOTES before disconnecting the battery.
2 Disconnect the battery ground cable P-5 at the battery.
3 Disconnect the generator positive lead P-9 from the generator . Connect the positive lead of a multimeter
set to measure current (1) to P-9 (2).
4 Connect that multimeter’s negative lead to the disconnected generator positive lead (3).
5 Connect the positive lead of a multimeter set to measure voltage (4) to P-9 (5).
6 Connect that multimeter’s negative lead to a good ground connection on the generator housing (6).

Insulate the terminal of the generator
positive lead P-9 to prevent contact with any
metal part of the vehicle. If the terminal is
grounded, damage to the charging circuit
can result when the battery is reconnected.
Figure 6D1-1 3

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7 Reconnect the battery ground cable P-5.
8 Fit a loading device (7) across the battery terminals, e.g. an adjustable carbon pile.

The loading device must have a minimum
power consumption of 1000 W.
9 Record the voltage reading before starting the engine. (This reading should increase when the engine is running, indicating generator output.).
10 Start the engine.
11 Increase the engine speed to the value outlined in the chart below.
12 Using the reading from the multimeter set to measure current, adjust the loading device to apply a load within the range outlined in the chart below.
13 Using the multimeter set to measure voltage, check the generator output voltage against the specification.
Engine RPM ........................................................... 1300
Load ................................................................ 5.0 – 10 A
Output Voltage ........................................... 13.8 – 15.4 V

Load Regulation Test
NOTE
The decrease in the voltage recorded during this
test should not exceed 0.5 V from the readings
obtained for the Regulating Voltage Test. If the
decrease in the regulating voltage is greater than
0.5 V, the regulator is defective. Replace the
regulator.
14 Increase the engine speed to the value outlined in the chart below.
15 Using the reading from the multimeter set to measure current, adjust the loading device to apply a load of about 90% of the generator’s full output.
16 Using the multimeter set to measure voltage, check the generator output voltage against the specification.
Engine RPM............................................................ 1900
Load ......................................................................... 90 A
Output Voltage ........................................... 13.8 – 15.4 V
Full Load Output Test

Keep the time for this test to a minimum to
avoid undue heating and high engine speeds.
17 Increase the engine speed to the value outlined in the chart below .
18 Using the reading from the multimeter set to measure voltage, adjust the loading device to increase the load until the generator output voltage drops to 13.5 V. Full generator output, outlined in the chart below, is required.
19 Record the current reading displayed on the multimeter set to measure current.

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20 Reduce the engine speed to idle.

On completion of the generator output test,
return the engine to idle and disconnect the
loading device from the battery terminals.
This prevents excessive battery discharge.
21 Stop the engine.
22 Disconnect the battery ground cable P-5 at the battery.
23 Remove the multimeters.
24 Reconnect the generator positive lead P-9.
25 Reconnect the battery ground cable P-5 to the battery.
Engine RPM............................................................ 1900
Load ................................................................ 5.0 – 10 A
Output Voltage ........................................... 13.8 – 15.4 V
Charging Circuit Voltage Drop Test
Prerequisites
Before testing the generator output, ensure that:
• all generator circuit connections are clean and tight,
• the generator is always connected to the battery during testing (to prevent damage to the diodes),
• the battery is fully charged, and
• the specific gravity does not vary more than 0.025 between cells. (It is recommended the average specific gravity
is 1.260 or higher). Refer to 6D1-3 Battery – V6.
Carry out a load test on the battery to determine its ability to supply and accept current. This is a good indicator of the
general condition of the battery. For details of battery testing, refer to 6D1-3 Battery – V6.
Inspect the drive belt and tensioner markings to determine if the drive belt is within operating limits. Replace the belt if it
is excessively worn or outside the operating range of the tensioner.
For further details, refer to 6A1 Engine Mechanical – V6.
Voltage Drop Test

Ensure the generator connections are clean
and tight.
1 Connect the positive lead of a multimeter set to measure voltage to the generator terminal P-9.
2 Connect the negative lead of the multimeter to the battery positive post.
3 Switch the headlamps on.
4 Start the engine.
5 Increase the engine speed to approximately 2500 r.p.m.
6 Record the voltage reading.
7 Reduce the engine speed to idle.

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8 Connect the positive lead of a multimeter set to measure voltage to the battery negative post.
9 Connect the negative lead of the multimeter to the generator housing.
9 Increase the engine speed to approximately 2500 r.p.m.
10 Record the voltage reading.
11 Reduce the engine speed to idle.
12 Check the two readings. If the readings exceed 0.3 V, there is a high resistance in the charging circuit.
13 Trace the cause and correct the problem, refer to 8A Electrical Body and Chassis.

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