2007 ISUZU KB P190 engine mount

Engine Management – V6 – General Information Page 6C1-1–12

Battery Voltage Correction Mode
The ECM monitors the battery voltage circuit to ensure the voltage available to the engine management system stays
within the specified range. A low system voltage changes the voltage across the fuel injectors, which affects the fuel
injector flow rate. In addition, a low system voltage fault condition may cause other engine management system
components to malfunction.
The ECM switches to battery voltage correction mode when the ECM detects a low battery voltage fault condition. W hile
in battery voltage correction mode, the ECM performs the following functions to compensate for the low system voltage:
• Increases the injector on-time to maintain the correct amount of fuel being delivered, and
• Increases the idle speed to increase the generator output.
Limp Mode
The programming in the ECM software allows the engine to run in a back-up fuel strategy or limp mode when the ECM
fails to receive signal inputs from critical sensors or when a critical engine management fault condition exists.
The ECM switches to limp mode to enable the vehicle to be driven until service operations can be performed.
Engine Protection Mode
Engine protection mode is engaged to protect engine components from friction damage in the event of an engine over-
temperature condition being detected by the ECM.
W hen the ECM is in engine protection mode, fuel injectors are systematically disabled and re-activated. The injectors
that have been shut down allow the air being drawn into the engine to assist with engine cooling.
Clear Flood Mode
If the engine is flooded with fuel during starting and will not start, the clear flood mode can be manually selected by
depressing the accelerator pedal to wide open throttle (W OT). In this mode, the ECM will completely disable the fuel
injectors, and will maintain this state during engine cranking as long as the ECM detects a W OT condition with engine
speed less than 1,000 rpm.
3.3 Ignition Control System
The electronic ignition system provides a spark to ignite the compressed air / fuel mixture at the correct time. The ECM
maintains correct spark timing and dwell for all engine operating conditions. The ECM calculates the optimum spark
parameters from information received from the various sensors and triggers the appropriate ignition module / coil to fire
the spark plug.
3.4 Starter Motor Operation
The engine control module controls the activation of the start relay in response to inputs from:
• Ignition switch,
• Battery,
• Immobiliser system, and
• Automatic transmission gear selector position / clutch pedal position switch for vehicles with manual transmissions.
3.5 Throttle Actuator Control System
Description
The throttle actuator control (TAC) system is used to improve emissions, fuel economy and driveability. The TAC system
eliminates the mechanical link between the accelerator pedal and the throttle plate and eliminates the need for a cruise
control module and idle air control motor. The TAC system comprises of:

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Engine Management – V6 – General Information Page 6C1-1–16

W hen ECM commands the EVAP valve (1) to open, the fuel
vapours are drawn from the canister line (2) into the intake
manifold where it is consumed in the normal combustion
process.

Figure 6C1-1 – 10
The ECM energises the EVAP valve when the appropriate conditions have been met, such as:
• Engine coolant temperature is less than 20 °C at cold start up and the engine has been running longer than
three minutes and 10 seconds, or
• Engine coolant temperature is greater than 80 °C and the engine has been running longer than five seconds, or
• Engine is not in decel fuel cut-off mode and the throttle opening is less than 96%, or
• The engine is in closed loop fuel mode.
A higher purge rate is used under conditions that are likely to produce large amounts of vapour, when the following
conditions have been met:
• Intake air temperature is greater than 50 °C, or
• Engine coolant temperature is greater than 100 °C, or
• The engine has been running for greater than 15 minutes.
The EVAP purge PW M duty cycle varies according to operating conditions determined by mass air flow, fuel trim and
intake air temperature. The EVAP canister purge valve is re-enabled when throttle position angle decreases below 96%.
For further information on the evaporative emission control system, refer to 6C Fuel System.
Engine Ventilation System
The engine ventilation system contains a Positive crankcase
ventilation (PCV) valve (1) located in the right-hand
camshaft cover. A hose is routed from the PCV valve to
each side of the intake manifold which provides an even
distribution of crankcase fumes, thereby improving spark
plug reliability and a reduction in emissions.
A breather pipe is routed from the intake manifold to the left-
hand camshaft cover and provides fresh filtered air from the
intake duct to the engine.
For further information of the engine ventilation system,
refer to 6A1 Engine Mechanical – V6.
Figure 6C1-1 – 11

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Engine Management – V6 – General Information Page 6C1-1–20

4.3 Barometric Pressure Sensor
The barometric pressure (BARO) sensor measures
barometric (atmospheric) pressure. The ECM uses this
signal to make corrections to the operating parameters of
the system based on changes in air density, since the
oxygen content of atmospheric air varies proportionally to air
density (barometric / atmospheric pressure). Barometric
pressure is affected mainly by altitude and climate.
The BARO sensor provides a voltage signal to the ECM that
is a function of barometric pressure. It does this through a
series of deformation resistors, which change resistance
when a mechanical force is applied. This force is applied to
the resistors by a diaphragm on which the atmospheric
pressure acts.
The ECM supplies the BARO sensor with a 5 V reference
and a ground circuit.
Figure 6C1-1 – 14
4.4 Camshaft Position Sensor
The HFV6 engine is fitted with an inlet camshaft position
(CMP) sensor.
The CMP sensor is used by the ECM to determine the
position of the camshafts. In conjunction with the crankshaft
position sensor, the CMP enables the ECM to determine
engine rotational position.
Figure 6C1-1 – 15
The CMP sensor operates on the dual-Hall sensing
principle. The sensor contains two hall elements (1) which
operate in conjunction with a two-track trigger wheel (2)
mounted on the camshaft.
As the tracks (3) on the trigger wheel pass the elements,
magnetic flux affects a voltage in the Hall elements. The
integrated circuit inside the sensor conditions the signal
generated by the Hall elements to provide a rectangular
wave on / off signal to the ECM.
The ECM supplies the CMP sensors with a 5 V reference
and ground circuit.
Figure 6C1-1 – 16

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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 6C1-1–26

The EOP sensor provides a voltage signal to the ECM that
is a function of engine oil pressure. It does this through a
series of deformation resistors (1), which change resistance
when a mechanical force is applied. This force is applied to
the resistors by a diaphragm on which the engine oil
pressure acts (2).
The sensor has an internal evaluation circuit (3) and is
provided with a 5 V reference voltage, a ground and a signal
circuit.

Figure 6C1-1 – 28
4.12 Fuel Injectors
A fuel injector is a solenoid device that is controlled by the
ECM. The six injectors deliver a precise amount of fuel into
each of the intake ports as required by the engine.

Figure 6C1-1 – 29
The fuel port (1) connects to the fuel rail. A strainer (2) is
provided in the port to protect the injector from fuel
contamination.
In the de-energised state (no voltage), the valve needle and
sealing ball assembly (3) are held against a cone-shaped
valve seat (4) by spring force (5) and fuel pressure.
W hen the injector is energised by the ECM, the valve
needle, which has an integral armature, is moved upward by
the injector solenoids magnetic field, un-seating the ball.
An orifice plate (6), located at the base of the injector has
openings that are arranged in such a way that two fuel
sprays emerge from the injector.
Each fuel spray is then directed at one of the intake valves,
causing the fuel to become further vaporised before entering
the combustion chamber.
Figure 6C1-1 – 30

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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 6C1-1–31

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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Engine Management – V6 – General Information Page 6C1-1–33

The knock sensor is tuned to detect the frequency of the
vibration created by combustion knock. The vibration is
transferred to the knock sensor through the cylinder
block (1).
Inside the sensor is a mass (2) that is excited by this
vibration, and the mass exerts a compressive force onto a
piezo-ceramic element (3). The compressive force causes a
charge transfer inside the element, so that an AC voltage
appears across the two outer faces (4) of the element. The
amount of the AC voltage produced is proportional to the
amount of knock.
Figure 6C1-1 – 42
4.18 Mass Air Flow Sensor
Air Intake System
The air intake system draws outside air through an air
cleaner assembly (1). The air is then routed through a mass
air flow (MAF) sensor (2) and into the throttle body and
intake manifold. The air is then directed into the intake
manifold runners, through the cylinder heads and into the
cylinders.
An arrow marked on the body of the MAF sensor indicates
correct air flow direction. The arrow must point toward the
engine.
Figure 6C1-1 – 43
Mass Air Flow Sensor
A hot film type mass air flow (MAF) sensor is used which
measures the air mass inducted into the engine, regardless
of the engine’s operating state. The MAF precisely
measures a portion of the total airflow and takes into
account the pulsation and reverse flows generated by the
engine’s inlet and exhaust valves.
Changes in intake air temperature have no effect on
measuring accuracy.
Figure 6C1-1 – 44

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