2007 ISUZU KB P190 width

Engine Cooling – V6 Engine Page 6B1–64

5 Specifications
General
Coolant Filler Cap Pressure Rating .............................................................................120 kPa
Cooling System Capacity
Automatic Transmission ........................................................................................ 9.9 litres
Manual Transmission .......................................................................................... 10.3 litres
Coolant Corrosion Inhibitor Quantity W hen Refilling System Automatic Transmission Models......................................................................... 5 litres
Manual Transmission Models .......................................................................... 5.2 litres
NOTE
DEX-COOL® long life coolant or equivalent such
as Extended Life Anti-freeze Coolant, conforming
to GM Specification 6277M, must be used when
changing coolant.
Thermostat Type...............................................................................................Power element (wax pellet)
Start to Open at ......................................................................................................... 82 ± 2 ° C
Fully Open at .......................................................................................................... 95° C ma x.
Coolant Pump
Type........................................................................................................................ Cen trifugal
Drive ................................................................................................ Multi-Vee Serpentine Belt
Bearing Type .................................................................................... Double Row Ball Bearing
Radiator
Core type ......................................................................................... Aluminium crossflow core
Overall width ................................................................................................................ 66 4 mm
Core width.................................................................................................................... 5 10 mm
Overall height............................................................................................................... 60 2 mm
Core height .................................................................................................................. 51 2 mm
Core thickness ............................................................................................................... 27 mm
Plastic Tanks .............................................................................. Nylon 6.6 (30% Glass Filled)
Radiator Hoses Lower Upper
Number ............................................................................... One............................. One
Type................................................................................ Moulded ...................... Moulded
Inside diameter ................................................................. 34 mm ........................ 34 mm

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ISUZU KB P190 2007

Engine Management – V6 – General Information Page 6C1-1–10

Fuel Injection System
Each cylinder of the V6 engine is fitted with one fuel injector. The engine control relay applies ignition positive voltage to
the fuel injector ignition circuit. The ECM controls the operation of the fuel injectors by applying a pulse width modulated
(PW M) ground to the fuel injector control circuit to control each fuel injector on-time.
W hile the engine is running, the ECM constantly monitors the various inputs and recalculates the appropriate on-time for
each injector. The calculation is based on the following:
• The injector flow rate,
• Mass of fuel passed by the energised injector per unit of time,
• The desired air / fuel ratio, and
• Actual air mass in each cylinder.
The ECM calculates the duration of the fuel injector on-time to deliver the correct amount of fuel for optimum drivability
and emission control. The period of time the fuel injector is energised is called the injector on-time and is measured in
milliseconds (thousandths of a second).
The V6 engine uses the sequential fuel injection system. Each fuel injector is energised individually at the correct
moment during its firing stroke as the cylinder’s intake valves are closing to provide enough time for the fuel to atomise
completely and mix with the intake air.
Short Term Fuel Trim
The short term fuel trim (STFT) represents the duration of the fuel injector on-time as calculated by the ECM, while the
ECM is in Closed Loop mode. The STFT allows the ECM to calculate the fuel injector on-time based on the heated
oxygen sensor (HO2S) signal input to the ECM. Therefore, the STFT is disabled when the ECM is in Open Loop mode.
• If the air / fuel mixture in the exhaust is balanced (lambda = 1) or when the STFT is disabled, the STFT value is 0%.
• W hen the HO2S sends an input signal to the ECM indicating the air / fuel mixture is rich, the STFT will be less than
0%, which indicates the ECM is decreasing the fuel injector on-time to reduce the amount of fuel in the air / fuel
mixture.
• W hen the HO2S sends an input signal to the ECM indicating the air / fuel mixture is lean, the STFT will be greater
than 0%, which indicates the ECM is increasing the fuel injector on-time to increase the amount of fuel in the air /
fuel mixture.
The percentage values of the STFT range from –25% to +25% and are directly proportional to the duration of the fuel
injector on-time.
Long Term Fuel Trim
The ECM stores the long term fuel trim (LTFT) in its memory to adjust the fuel injector on-time according to the long term
changes or deterioration in the engine components. The normal LTFT value is 0%.
The following describes the LTFT operation when the engine air filter is dirty that causes a restricted intake airflow fault
condition:
1 The HO2S sends an input signal to the ECM the air / fuel mixture is rich because of the reduced airflow. The STFT may reduce to a value of –10%, which decreases the fuel injector on-time to reduce the amount of fuel in the air /
fuel mixture supplied to the engine.
W ithout the use of the LTFT, the restricted airflow caused by the dirty air filter may reduce the STFT value to –10% until the air filter is replaced. This will decrease the range of negative adjustment available to the STFT to
compensate for other factors.
2 W hen the ECM detects the STFT has remained at –10% for a specific period, the ECM switches to the LTFT. The LTFT adjusts the duration of the fuel injector on-time until the air / fuel mixture in the exhaust is balanced (lambda =
1) and the STFT value returns to 0%.
3 The ECM stores this Long Term FT value in its memory, which is used to calculate the base fuel injector on-time.
The percentage values of the Long Term FT range from –100% to +100%. If the ECM detects the LTFT values are
outside the specified percentage range for a predetermined period, the ECM will set a Diagnostic Trouble Code and
switch to Open Loop mode.

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ISUZU KB P190 2007

Engine Management – V6 – General Information Page 6C1-1–11

3.2 Air / Fuel Control System
The engine control module (ECM) controls the amount of air and fuel delivered into each of the engine cylinders. Based
on the various ECM inputs, the ECM switches to the following air / fuel control system mode to provide the optimum air /
fuel ratio under all engine operating conditions.
Starting Mode
W hen the ignition switch is moved to the START position and the engine begins to turn, a prime pulse may be injected to
speed starting. As soon as the ECM receives an input signal from the camshaft position (CMP) and crankshaft position
(CKP) sensor and determines which cylinder is in the firing stroke, the ECM applies a pulse width modulated (PW M)
ground to the injector control circuit. The ECM monitors mass air flow, intake air temperature, engine coolant
temperature, and throttle position to determine the required fuel injector on-time required for starting the engine.
Run Mode
The engine switches to run mode when the engine speed reaches 480 rpm after being started. The run mode has two
sub-modes called Open Loop and Closed Loop.
Open Loop Mode
The heated oxygen sensor (HO2S) does not produce a usable signal voltage output until it reaches operating
temperature. Therefore, while the HO2S is below its operating temperature, the ECM switches to open loop mode.
In open loop, the ECM ignores the signals from the HO2S and calculates the required injector pulse width based
primarily on inputs from the mass air flow (MAF), intake air temperature (IAT), and engine coolant temperature sensors.
The system will stay in the open loop mode until the HO2S produce a usable output.
Closed Loop Mode
Once the HO2S reaches operating temperature and starts producing its own signal voltage output, the ECM switches to
the closed loop mode.
In closed loop mode, the ECM initially calculates injector pulse width based on the same sensors used in open loop, and
additionally the ECM uses the oxygen sensor signals to modify and fine tune the fuel pulse width calculations to precisely
maintain the ideal 14.7 to 1 air / fuel ratio.
Acceleration Mode
The ECM monitors and calculates input signals from the accelerator pedal position (APP) and MAF sensor signals to
determine when the vehicle is being accelerated. If the ECM detects the accelerator pedal is depressed and there is a
demand for the vehicle to accelerate, the ECM switches to acceleration mode. In acceleration mode, the ECM increases
the fuel injector on-time to provide more fuel accordingly.
Deceleration Mode
The ECM monitors and calculates input signals from the APP and MAF sensor signals to determine when the vehicle is
being decelerated. If the ECM detects the vehicle is decelerating, the ECM switches to deceleration mode. In
deceleration mode, the ECM decreases the fuel injector on-time, or disables the fuel injectors for short periods, to reduce
exhaust emissions and improve fuel economy.
Fuel Shut-off Mode
To protect the engine from damage or to improve the vehicle's driveability, the ECM switches to the fuel shut-off mode. In
fuel shut-off mode, the ECM performs the following:
• The ECM disables the six fuel injectors under the following conditions:
− Ignition off – to prevent engine dieseling,
− Ignition on but no ignition reference signal – prevents flooding or backfiring,
− At high engine speed – greater than the red line (rev limiter),
− At high vehicle speed – greater than the rated tire speed (vehicle speed limiter), or
− Extended high speed closed throttle coast-down – reduces engine emissions and increases engine braking.
• The ECM selectively disables the appropriate number of fuel injectors when torque management has been enabled.

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Engine Management – V6 – General Information Page 6C1-1–15

W hen the cruise control ON-OFF switch, located on the right hand side of the dash panel, is pressed, the PIM, on
receiving the input from the switch, turns on the cruise ON-OFF switch warning lamp to inform the user that the cruise
control has been engaged.
W hen the cruise control switch assembly is pressed to SET/COAST, the PIM on receiving the input, sends a signal via
the serial data bus to the ECM. Providing the pre-conditions for cruise control operation have been met, the ECM
activates cruise control and commands the PIM to turn on the instrument cluster cruise set warning lamp, to inform the
user that cruise control is active. The ECM receives all the various inputs required to maintain the correct speed and then
controls the throttle plate depending on the load on the engine (ascending or descending hills, etc).
The cruise control is deactivated by either pressing the brake pedal, clutch pedal, cruise CANCEL or by the cruise control
ON-OFF button. In each of these instances, the ECM receives an input when any of these switches are activated. For
further information on the cruise control system, refer to 8C Cruise Control – HFV6.
3.7 Brake Torque Management
Brake torque management places limits on engine torque when the brakes are applied, regardless of the accelerator
pedal position (APP). The conditions under which brake torque management occur are as follows:
• The accelerator has been depressed before the brakes are applied,
• The brakes are applied and the ECM receives an input from the stop lamp switch,
• Vehicle speed is greater than 5 km/h,
• Engine speed is greater than 1200 rpm and
• Conditions exist for greater than 2.5 seconds.
W hen brake torque management has been implemented, the torque is reduced by altering the throttle plate opening by
25%. The ECM will monitor the rate at which the vehicle is slowing and adjust the throttle plate opening accordingly.
3.8 Emission Control Systems
Evaporative Emission Control System
The evaporative emission control system used is the
activated carbon (charcoal) canister storage method. Fuel
vapour is drawn from the fuel tank into the canister where it
is held by the activated carbon until the ECM commands the
evaporative emission (EVAP) purge solenoid valve to open.
The ECM energises the EVAP purge solenoid valve by
applying a pulse width modulated (PW M) ground to the
EVAP purge solenoid valve control circuit.
Figure 6C1-1 – 9

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Engine Management – V6 – General Information Page 6C1-1–23

4.8 Engine Coolant Temperature Sensor
The engine coolant temperature (ECT) sensor is a
thermistor, which is a resistor that changes it’s resistance
value based on temperature.
Figure 6C1-1 – 21
The ECT is mounted in the engine coolant stream and as it
is a negative temperature coefficient (NTC) type, low engine
coolant temperature produces a high sensor resistance
while high engine coolant temperature causes low sensor
resistance.
Legend
A Temperature
B Resistance
The ECM provides a 5 V reference signal to the ECT and
monitors the return signal which enables it to calculate the
engine temperature.
The ECM uses this signal to make corrections to the
operating parameters of the system based on changes in
engine coolant temperature.
Figure 6C1-1 – 22
4.9 Electric Cooling Fan
The ECM controls the operation of the electric engine
cooling fan. The ECM applies a pulse width modulated
(PW M) signal to the cooling fan motor to control the fan
speed based on current vehicle conditions. For further
information on cooling fan operation, refer to 6B1 Engine
Cooling – V6.

Figure 6C1-1 – 23

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Engine Management – V6 – General Information Page 6C1-1–27

4.13 Fuel Rail Assembly
The fuel rail assembly is mounted on the lower intake
manifold and distributes the fuel to each cylinder through
individual fuel injectors. The fuel rail assembly consists of:
• the pipe that carries fuel to each injector,
• a fuel pressure test port,
• six individual fuel injectors,
• wiring harness, and
• wiring harness tray.
Figure 6C1-1 – 31
4.14 Heated Oxygen Sensors
The heated oxygen sensors (HO2S) are mounted in the exhaust system and enable the ECM to measure oxygen
content in the exhaust stream. The ECM uses this information to accurately control the air / fuel ratio, because the
oxygen content in the exhaust gas is indicative of the air / fuel ratio of engine combustion.
W hen the sensor is cold, it produces little or no signal voltage, therefore the ECM only reads the HO2S signal when the
HO2S sensor is warm. As soon as the HO2S are warm and outputting a usable signal, the ECM begins making fuel
mixture adjustments based on the HO2S signals. This is known as closed loop mode.
The HFV6 engine has four HO2S, one LSU 4.2 wide-band planar type HO2S upstream of the catalytic converter in each
exhaust pipe, and one LSF 4.2 two-step planar type HO2S in each exhaust pipe downstream of the catalytic converter.
LSF 4.2 Two-step Planar Heated Oxygen Sensors
The LSF 4.2 two-step planar heated oxygen sensors have
four wires:
• The internal heater element supply, which has 12 V
continually applied whenever the ignition is on.
• Heater element ground – The ECM applies pulse
width modulated (PW M) ground to the HO2S heater
control circuit to control the rate at which the sensor
heats up. This reduces the risk of the sensor being
damaged from heating up too quickly under certain
conditions such as extreme cold temperatures. Once
the sensor has reached the desired operating
temperature, the ECM will monitor and continue to
maintain the sensor temperature.
• Sensor signal to the ECM.
• Sensor ground.
Legend
1 Protective Tube
2 Ceramic Seal Packing
3 Sensor Housing
4 Ceramic Support Tube
5 Planar Measuring Element
6 Protective Sleeve
7 Connection Cable
Figure 6C1-1 – 32

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Engine Management – V6 – General Information Page 6C1-1–29

LSU 4.2 Wide-band Planar Heated Oxygen Sensors
The LSU 4.2 wide-band planar heated oxygen sensors have
six wires:
• The internal heater element supply, which has 12 V
continually applied whenever the ignition is on.
• Heater element ground – The ECM applies pulse
width modulated (PW M) ground to the HO2S heater
control circuit to control the rate at which the sensor
heats up. This reduces the risk of the sensor being
damaged from heating up too quickly under certain
conditions such as extreme cold temperatures. Once
the sensor has reached the desired operating
temperature, the ECM will monitor and continue to
maintain the sensor temperature.
• Output voltage.
• Sensor ground.
• Trim current.
• Pumping current.
Legend
1 Measuring Cell (Nernst cell and pump cell)
2 Double Protective Tube
3 Seal Ring
4 Seal Packing
5 Sensor Housing
6 Protective Sleeve
7 Contact Holder
8 Contact Clip
9 PTFE Sleeve (Teflon)
10 PTFE Shaped Sleeve
Figure 6C1-1 – 35

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Engine Management – V6 – General Information Page 6C1-1–31

4.15 Ignition Coil and Spark Plug
Long-life platinum tip spark plugs are used which, along with
the ignition coil spark plug boot and spring, require
replacement at 100,000 kilometre service intervals. The
spark plugs, featuring a J-gap and a conical seat, do not
require inspection between services, and must not be re-
gapped.
Individual pencil-type ignition coils, one for each cylinder, are
mounted in the centre of the camshaft covers, and have
short boots connecting the coils directly to the spark plugs.
The pencil coil makes use of the space available in the spark
plug cavity in the cylinder head and camshaft cover. As a
pencil coil is always mounted directly on to the spark plug,
no high-tension ignition leads are required, further enhancing
reliability.

Figure 6C1-1 – 38
Pencil coils operate similarly to other compact coils, however
due to their shape, the structure differs considerably.
The central rod core (1) consists of laminations of varying
widths, stacked in packs that are nearly spherical. A yoke
plate (2), made from layered electrical sheet steel, provides
the magnetic circuit. The primary winding (3) is located
around the secondary winding (4), which supports the core.
A printed circuit board, or driver module, (5) is located at the
top of the coil and controls the firing of the coil based on
input from the ECM.
The ECM is responsible for maintaining correct spark timing
and dwell for all driving conditions. The ECM calculates the
optimum spark parameters from information received from
the various sensors, and triggers the appropriate ignition
module which then operates the coil.
The ignition coil / modules are supplied with the following
circuits:
• Ignition feed circuit.
• Ground circuit.
• Ignition control circuit.
• Reference low circuit.

Figure 6C1-1 – 39

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