engine mount ISUZU KB P190 2007 Workshop Repair Manual

Fuel System – V6 Page 6C – 12


A small amount of fuel may be released when
pressing on the Schrader valve. Cover the
fitting with a shop towel to absorb any fuel
spillage before removing the Schrader valve
sealing cap. Place the soiled towel in an
approved container for disposal.
7 At the fuel pressure test point (2), remove the Schrader valve sealing cap (1), refer to Figure 6C – 7.

Figure 6C – 7
Legend
1 Schrader Valve Sealing Cap
2 Pressure Test Point 3 Schrader Valve

Wear safety glasses when performing the fuel
pressure relief procedure.
8 Place a shop towel around the Schrader valve to soak up the expelled petrol.
9 Use a small screwdriver to press the Schrader valve down (3).
10 Remove the soiled shop towel and place in an approved container.
Repressurise
1 Reinstall the fuel pump relay and fuel pump fuse.
2 Perform the following procedure to inspect for leaks at the fuel pressure test point: a Turn the ignition switch on for two seconds.
b Turn the ignition switch off for 10 seconds.
c Turn the ignition switch on.
d Check for leaks at the fuel pressure test point.
3 Tighten the fuel filler cap.
4 Start the engine and recheck for leaks.
5 Reinstall the Schrader valve sealing cap.

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Fuel System – V6 Page 6C – 15

Reinstall
1 Apply a small amount of engine oil or light oil to the
fuel line to assist in the assembly of the connector.


NOTE
Assembly of the fuel line and quick connectors
should take place immediately after applying the
oil to prevent any dust from sticking to the
surface, which may cause the connector to leak.
Figure 6C – 12
4.2 Fuel Filter
Removal
1 Depressurize the fuel system, refer to 3.4 Fuel
System Depressurisation.
2 Disconnect the battery ground cable.

A small amount of fuel will flow out of the
fuel lines and filter when disconnected.
3 Locate the fuel filter attached to the front of the fuel tank, place a drain tray below the fuel filter and
remove the fuel line quick connectors from the inlet
(2) and the outlet (1) of the fuel filter, refer to 4.1 Fuel
Lines And Quick Connect Fittings.
Figure 6C – 13

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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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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 6C1-1–12

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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