start ISUZU KB P190 2007 Workshop Repair Manual

Fuel System – V6 Page 6C – 13

4 Service Operations
4.1 Fuel Lines And Quick Connect Fittings
Description
The fuel line connector fittings contain the following
components:
1 O-rings
2 Fuel line port
3 Connector
4 Plastic fuel line tube

Figure 6C – 8

Leak Test and Inspection
1. Turn the ignition key to the ON position and ensure the fuel pump runs for a short time by listening for the pump start up sound. The fuel pressure will increase when the fuel pump is actuated.
2 Perform a preliminary check of the system by inspecting the system for any leaks around the connections and fittings.
3 Perform steps 1 and 2 several times.
4 If the preliminary check of the system produces no leaks, start the engine and check the system again for any sign of leaks around the connections and lines.

Ensure all service precautions have been
observed prior to removing any connector
fittings.


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Fuel System – V6 Page 6C – 22

Reinstall
Reinstallation of the fuel tank is the reverse of the removal procedure, noting the following:
1 Lift the fuel tank into position reinserting the fuel tank inlet and breather hoses into the body opening. Raise the fuel tank into place and rest the front of the tank on the crossmember.
2 Replace the fuel pump electrical connector, be sure to engage the locking tab.
3 Fit the fuel tank mounting straps in the following order, refer to Figure 6C – 17, a Loosely reattach the rear fuel tank mounting strap and bolt (8 & 9), refer to Figure 6C – 17.
b Loosely attach the front mounting strap and bolt (1 & 2), refer to Figure 6C – 17.
c Ensure that the fuel tank is located in the correct position then,
d Tighten the rear mounting strap bolt (8), Figure 6C – 17.
e Tighten the front mounting strap bolt (1), Figure 6C – 17.
4 Tighten all fuel tank mounting strap bolts to the correct torque specification.
Fuel tank mounting strap bolts
torque specification ............................................68.0 Nm

Install the fuel filter with the flow arrow on its
body pointing in the same direction as the
fuel flow to the front of the vehicle.
5 Install the disconnected quick-connect fittings to the fuel supply line at the front of the fuel tank and the evaporative line quick-connect fitting at the rear of the fuel tank. Refer to 4.1 Fuel Lines And Quick Connect Fittings, for the
correct component routeing.
6 Lower the vehicle to a comfortable working height and reinstall the clamp (1) to the fuel filler neck and reconnect the rubber fuel tank inlet hose (2) and tighten the clamp, refer to Figure 6C – 21.
7 Reinstall the fuel tank breather hose (3) to the fuel filler neck (1) and tighten the clamp (2), refer to Figure 6C – 20.
8 Clip the fuel filler door release cable (1) to the retainer on the fuel filler neck (2), refer to Figure 6C – 19.
9 Locate the fuel filler neck (3) to the filler pocket and attach with the securing screw (2), remove the cover material from the fuel filler neck inlet and refit the fuel filler cap (4), refer to Figure 6C – 18.
10 Reinstall the front half of the right-hand rear wheelhouse liner, refer to 10 Cab.
11 Before starting the vehicle, perform a fuel system leak test, refer to 3.3 Fuel Leak Test.



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

6C1-1 Engine Management – V6
General Information
ATTENTION
Before performing any service operation or other procedure described in this Section, refer to 1.3 Warning
Caution and Notes for correct workshop practices with regard to safety and / or property damage.
1 General Information ............................................................................................................ ...................3
1.1 Introduction ............................................................................................................................................................ 3
1.2 Emission Control ................................................................................................................................................... 3
ADR 79/01 Emissions Standards .......................................................................................................................... 3
1.3 Warning Caution and Notes .................................................................................................................................. 4
Definition of WARNING, CAUTION and NOTE Statements ............................................................................. .... 4
WARNING defined ............................................................................................................................................. 4
CAUTION defined .............................................................................................................................................. 4
NOTE defined..................................................................................................................................................... 4
2 Component Locations ............................................................................................................ ...............5
2.1 Cylinder Numbering............................................................................................................................................... 5
2.2 Engine Compartment............................................................................................................................................. 5
2.3 Engine ..................................................................................................................................................................... 6
2.4 Interior..................................................................................................................................................................... 8
3 System Operation ...................................................................................................................................9
3.1 Fuel Delivery System ............................................................................................................................................. 9
Fuel System Pressure ........................................................................................................... ................................ 9
Fuel Injection System .......................................................................................................................................... 10
Short Term Fuel Trim ....................................................................................................................................... 10
Long Term Fuel Trim ........................................................................................................................................ 10
3.2 Air / Fuel Control System ...................................................................................................... .............................. 11
Starting Mode ....................................................................................................................................................... 11
Run Mode.............................................................................................................................................................. 11
Open Loop Mode................................................................................................................. ............................. 11
Closed Loop Mode ............................................................................................................... ............................ 11
Acceleration Mode .............................................................................................................. ................................. 11
Deceleration Mode ............................................................................................................................................... 11
Fuel Shut-off Mode .............................................................................................................................................. 11
Battery Voltage Correction Mode ................................................................................................ ....................... 12
Limp Mode ............................................................................................................................................................ 12
Engine Protection Mode ......................................................................................................... ............................. 12
Clear Flood Mode ................................................................................................................................................. 12
3.3 Ignition Control System........................................................................................................ ............................... 12
3.4 Starter Motor Operation....................................................................................................................................... 12
3.5 Throttle Actuator Control System ............................................................................................... ....................... 12
Description ........................................................................................................................................................... 12
Throttle Body Relearn Procedure ....................................................................................................................... 14
TAC System Default Actions / Reduce Power Modes................................................................................ ....... 14
Forced Engine Shutdown .................................................................................................................................... 14
3.6 Cruise Control System ........................................................................................................................................ 14
3.7 Brake Torque Management ........................................................................................................ ......................... 15
3.8 Emission Control Systems.................................................................................................................................. 15
Evaporative Emission Control System ............................................................................................ .................. 15
Engine Ventilation System .................................................................................................................................. 16

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Engine Management – V6 – General Information Page 6C1-1–9

3 System Operation
The engine control module (ECM) is the control centre of the V6 engine management system. The ECM constantly
monitors and evaluates inputs from various sensors and switches. Based on these inputs, the ECM controls the
operation of the engine management system. Refer to Figure 6C1-1 – 6 for the illustration of the inputs and outputs of
the ECM.

Figure 6C1-1 – 6
3.1 Fuel Delivery System
Fuel System Pressure
W hen the ignition switch is turned on, the ECM energises the fuel pump circuit and the fuel pump runs and builds up
pressure in the fuel system. The fuel pump will continue to operate if the engine is started or as long as the engine is
cranking or running and the ECM detects crankshaft position (CKP) sensor signal pulses. If the CKP sensor signal
pulses stop, the ECM de-energises the fuel pump circuit within two seconds, which stops the fuel pump operation.
The vehicle is fitted with a modular fuel pump and sender assembly that provides delivery of fuel from the fuel tank and
information on the fuel level. The fuel delivery system is a single line, on-demand design. W ith the fuel pressure regulator
incorporated into the modular fuel pump and sender assembly, the need for a return pipe from the engine is eliminated.
The electric fuel pump contained in the modular fuel pump and sender assembly provides fuel at a pressure greater than
the regulated pressure which is supplied to the fuel rail. The fuel is then distributed through the fuel rail to six injectors
located directly above each cylinder’s two intake valves.
Having a single line fuel supply system reduces the internal temperature of the fuel tank by not returning hot fuel from the
engine. In reducing the internal temperature of the fuel tank, lower evaporative emissions are achieved.
Unleaded fuel must be used to ensure correct emission parameters and engine operation. Leaded fuel damages the
emission control system and use of leaded fuel can result in loss of emission warranty. Using unleaded fuel will also
minimise any spark plug fouling and extend engine oil life.

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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 6C1-1–14

Throttle Body Relearn Procedure
The ECM stores values that include the lowest possible TP sensor positions (zero percent), the rest positions (seven
percent), and the spring return rate. These values will only be erased or overwritten if the ECM is reprogrammed or if a
throttle body relearn procedure is performed.
NOTE
If the battery has been disconnected, the ECM
performs a throttle body relearn procedure once
the battery has been reconnected and the ignition
turned on.
The ECM performs a throttle body relearn procedure anytime the ignition is turned on and the following conditions have
been met:
• The engine has been off for greater than 29 seconds,
• The engine speed is less than 40 rpm,
• The vehicle speed is 0 km/h,
• The engine coolant temperature (ECT) is 5 – 60°C; if Tech 2 is used to perform the relearn procedure, the ECT is
5 – 100°C,
• The intake air temperature (IAT) is greater than 5 – 60°C; if Tech 2 is used to perform the relearn procedure, the
IAT is 5 – 100°C,
• The APP sensor angle is less than 15 percent, and
• Ignition voltage is greater than 10 V.
The throttle body relearn procedure is performed 29 seconds after the ignition is turned on. The ECM commands the
throttle plate from the rest position (seven percent open) to full closed (zero percent), then to around 10 percent open.
This procedure takes about six – eight seconds. If any faults occur in the TAC system, a DTC sets. At the start of this
procedure, the Tech 2 TAC Learn Counter parameter should display 0, then count up to 11 after the procedure is
completed. If the counter did not start at 0, or if the counter did not end at 11, a fault has occurred and a DTC should set.
TAC System Default Actions / Reduce Power Modes
The ECM switches to the following reduce power modes if the ECM detects a fault condition in the TAC system:
• If an APP sensor circuit fault or TP sensor circuit fault is detected, the ECM limits engine torque so the vehicle
cannot reach speeds of greater than 100 km/h. The ECM remains in this reduce power mode during the entire
ignition cycle, even if the fault is corrected.
• If there is a fault condition with the throttle actuator control circuits, a throttle actuator command vs. actual position
fault, a return spring check fault, or a TP sensor one circuit fault, the ECM limits engine speed to 2500 rpm and
three – six fuel injectors are randomly disabled. At this time the reduce power indicator is commanded on. The
ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected.
NOTE
If a TP sensor one or throttle actuator control
circuit fault is present at the time the vehicle is at
idle, with no accelerator pedal angle, the engine
may stall.
Forced Engine Shutdown
A further safety feature which is built into the TAC system is the ECM will initiate an engine shut down if, the ECM’s
internal monitoring functions detects a serious internal fault, the fuel injectors will be turned off.
3.6 Cruise Control System
The cruise control system integrates with the engine control module (ECM) through the powertrain interface module
(PIM), to control the electronic throttle actuator and maintain the vehicle at the speed set by the driver.

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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 6C1-1–17

3.9 Serial Data Communication System
The engine control module (ECM) communicates directly with the following control units using the General Motors local
area network (GM LAN) serial data communication protocol:
• Transmission control module (TCM) (if fitted)
• Powertrain interface module (PIM)
The immobiliser control unit (ICU) communicates directly with the PIM using Keyword 2000 serial data communication
protocol. Refer to 11A Immobiliser for further information
As the GM LAN serial data communication protocol is not compatible with the Keyword 2000 serial data communication
protocol, a powertrain interface module (PIM) is integrated to the serial data communication system to perform the
following tasks (Refer to 6E1 Powertrain Interface Module – V6):
• Translate the GM LAN serial data transmitted by the ECM into a Keyword 2000 serial data that can be received
and recognised by the ICU.
• Translate the cruise control switch, automatic transmission power mode switch and 3
rd start switch signal into a GM
LAN serial data that can be received and recognised by the ECM.
3.10 Self Diagnostics System
The ECM constantly performs self-diagnostic tests on the engine management system. W hen the ECM detects a
malfunction, it also stores a diagnostic trouble code (DTC). A stored DTC will identify the problem area(s) and is
designed to assist the technician in rectifying the fault. In addition, DTCs are classified as either Current or History DTC.
Depending on the type of DTC set, the ECM may turn on the
malfunction indicator lamp (MIL) (1) to warn the driver there
is a fault in the Engine Management System.
Figure 6C1-1 – 12
3.11 Service Programming System
The ECM has an Electronically erasable programmable read only memory (EEPROM) where the software and
calibration information required to operate the engine management system are stored.
The ECM features a service programming system (SPS) to flash program the EEPROM in the ECM with the latest ECM
software to provide optimum performance, driveability and emissions control or to program a new ECM.
Flash programming refers to the SPS used to transfer (or download) ECM data from a computer terminal to the vehicle’s
ECM. The system is designed so the vehicle verification procedures are required to eliminate EEPROM tampering that
could increase engine emission levels.
There are three main flash programming techniques:
1 Direct programming (pass through). This is where the vehicle’s data link connector (DLC) is connected directly to a computer terminal. On screen directions are then followed for downloading.
2 Remote Programming. Reprogramming information is downloaded from a computer terminal to Tech 2. Tech 2 is then connected to the vehicle’s DLC. On screen directions are then followed for downloading.
3 Off-board Programming. The off-board programming method is used when a re-programmable ECM must be programmed while it is removed from the vehicle. For example, an independent repair facility may find it necessary
to replace a faulty ECM. On flash programming equipped vehicles, the replacement ECM must be programmed
with data for the specific vehicle identification number (VIN) or the vehicle may not operate properly.

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Engine Management – V6 – General Information Page 6C1-1–18

3.12 Immobiliser System
The vehicle incorporates an immobiliser system. After the ignition switch is turned to the ON position, and the powertrain
interface module (PIM) has authenticated the immobiliser control unit (ICU), the PIM sends an encrypted security code to
the engine control module (ECM). The ECM compares the received security code with its own security code, and if it is
valid, the ECM enables the vehicle to be started. For further information and diagnosis of the immobiliser system, refer to
11A Immobiliser.
For further information on the PIM, refer to 6E1 Powertrain Interface Module – V6.

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