engine ISUZU KB P190 2007 Workshop Repair Manual

6E-284 Engine Control System (4JH1)
Important:
To prevent possible electrostatic discharge damage,
follow these guidelines: • Do not touch the ECM connector pins or soldered
components on the ECM circuit board.
• Do not open the replacement part package until
the part is ready to be installed.
• Before removing the part from the package,
ground the package to a known good ground on
the vehicle.
• If the part has been handled while sliding across
the seat, while sitting down from a standing
position, or while walking a distance, touch a
known good ground before installing the part.
• Charge by induction occurs when a person with
well insulated shoes stands near a highly charged
object and momentarily touches ground. Charges
of the same polarity are drained off leaving the
person highly charged with opposite polarity.
Malfunction Indicator Lamp (MIL) Operation
The malfunction indicator lamp (MIL) is located in the
instrument panel cluster (IPC). The MIL will display the
following symbols when commanded ON:



RTW 76ESH004001
The MIL indicates that an emission or performance
related fault has occurred and vehicle service is
required. The following is a list of the modes o
f
operation for the MIL: • The MIL illuminates for approximately 2 seconds
when the ignition switch is turned ON, with the
engine OFF. This is a bulb test to ensure the MIL
is able to illuminate.

•
The MIL remains illuminated after the engine is
started if the ECM detects a fault. A DTC is stored
any time the ECM illuminates the MIL due to an
emission or performance related fault.

Engine Control Component Description
Accelerator Pedal Position (APP) Sensor & Idle
Switch






RTW 66ESH001301
The accelerator pedal position (APP) sensor is mounted
on the throttle assembly. The engine control module
(ECM) uses the APP sensor s to determine the amount
of acceleration or deceleration desired by the person
driving the vehicle via the fuel injection control.
The idle switch is also mounted on the intake throttle
assembly. The idle switch is part of the APP senso
r
assembly. The idle switch is a normally closed type
switch. W hen the accelerator pedal is released, the idle
switch signal to the ECM is low voltage.








BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-285
Crankshaft Position (CKP) Sensor










RTW 06ESH000101




RTW 66ESH001401
Legend
1. Crankshaft Position (CKP) Sensor
2. Flywheel
3. Slit

The crankshaft position (CKP) sensor is located on top
of the flywheel housing. There are 4 slits spaced 90 °
on the flywheel circumference. The CKP sensor is a
magnetic coil type sensor , which generates an AC
signal voltage based on the crankshaft rotational speed.
The ECM monitors both the CKP sensor and injection
pump camshaft position (CMP) sensor signals to
ensure they correlate with each other.

The following waveform aids to diagnose when there is
an oscilloscope or equivalent.

Engine Coolant Temperature (ECT) Sensor
- Amplitudes of CKP sensor signal (CH1) increase as engine speed increases.
- Each waveform cycle shorten as the engine speed increases.
Terminal: 90 (CH1), 91 (CH2) (+) / GND (-)
Scale: 10V/div 2ms/div
Condition: Approximately 1000RPM

CH1
0V
CH2 0V


RTW 66ESH001501
Legend
1. Engine Coolant Temperature (ECT) Sensor

The engine coolant temperature (ECT) sensor is
installed to the thermostat housing. The ECT sensor is
a variable resistor. The ECT sensor measures the
temperature of the engine coolant. The engine control
module (ECM) supplies 5 volts to the ECT signal circuit
and a ground for the ECT low reference circuit. W hen
the ECT sensor is cold, the sensor resistance is high.
W hen the engine coolant temperature increases, the
sensor resistance decreases. W ith high senso
r
resistance, the ECM detects a high voltage on the ECT
signal circuit. W ith lower sensor resistance, the ECM
detects a lower voltage on the ECT signal circuit.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-286 Engine Control System (4JH1)
Exhaust Gas Recirculation (EGR) Solenoid Valve



RTW 76ESH003601
The engine control module (ECM) controls the exhaust
gas recirculation (EGR) flow amount based on the
engine speed, engine coolant temperature, intake ai
r
temperature, barometric pressure and fuel injection
quantity. The ECM controls the EGR valve b
y
controlling the EGR solenoid valve. The mass air flo
w
(MAF) sensor monitors EGR gas flow amount. An
expected MAF amount should be detected while the
engine running.

Intake Air Temperature (IAT) Sensor



RTW 66ESH001701
The intake air temperature (IAT) sensor is fitted
between the air cleaner and turbocharger internal to the
mass air flow (MAF) sensor. The IAT sensor is a
variable resistor. The IAT sensor measures the
temperature of the air entering the engine. The engine
control module (ECM) supplies 5 volts to the IAT signal
circuit and a ground for the IAT low reference circuit.
W hen the IAT sensor is cold, the sensor resistance is
high. W hen the air temperature increases, the senso
r
resistance decreases. W ith high sensor resistance, the
ECM detects a high voltage on the IAT signal circuit.
W ith lower sensor resistance, the ECM detects a lowe
r
voltage on the IAT signal circuit.
Mass Air Flow (MAF) Sensor



RTW 66ESH001701
The mass air flow (MAF) sensor is an air flow meter that
measures the amount of air that enters the engine. It is
fitted between the air cleaner and turbocharger. A small
quantity of air that enters the engine indicates
deceleration or idle. A large quantity of air that enters
the engine indicates acceleration or a high load
condition. The MAF sensor assembly consists of a MAF
sensor element and an intake air temperature senso
r
that are both exposed to the air flow to be measured.
The MAF sensor element measures the partial air mass
through a measurement duct on the sensor housing.



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-287
Vehide Speed Sensor (VSS)



RTW 56EMH000301
Legend
1. Vehicle Speed Sensor (VSS) 2W D with A/T
2. Vehicle Speed Sensor (VSS) except 2W D with A/T


The vehicle speed sensor (VSS) is used by the engine
control module (ECM) and speedometer, which
generates a speed signal from the transmission output
shaft. The VSS uses a hall effect element. It interacts
with the magnetic field created by the rotating magnet
and outputs square wave pulse signal. The ECM
calculates the vehicle speed by the VSS.

The following waveform aids to diagnose when there is
an oscilloscope or equivalent. - VSS waveform cycle shorten as the vehicle speed increases.
Terminal: 68 (+) / GND (-)
Scale: 5V/div 50ms/div
Condition: Approximately 20km/h (12MPH)


0V


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-288 Engine Control System (4JH1)
Fuel Injection System Description




RTW 66EMF000401
Legend
1. Drive Shaft
2. Fuel Feed Pump
3. Pump Camshaft Position (CMP) Sensor
4. Fuel Injection Pump Control Unit (PCU)
5. Distributor Head
6. Constant Pressure Valve (CPV) Holder


7. Fuel Injection Solenoid Valve
8. Constran Pressure Valve (CPV)
9. Timing Control Valve (TCV)
10. Timer
11. Radial Plunger


Bosch VP44 Fuel Injection Pump
Instead of the previous face cam type, the radial
plunger distributor type injection pump utilizes a cam
ring to enable fuel injection at high-pressures, marking it
suitable for small, high-speed direct injection diesel
engines. This pump was developed to provide the most
suitable fuel injection quantity and injection timing to
satisfy the demand for engine reliability, driveability, lo
w
smoke, low noise, high output and low exhaust
emissions.
The engine control module (ECM) calculates the
desired fuel injection quantity and timing using data sent
from various sensor s. These desired data are sent to
the fuel injection pump control unit (PCU) via a
controller area network (CAN) communication bus. The
PCU also receives signals from the internal inputs:
pump camshaft position (CMP) sensor that is located
inside the fuel injection pump to determine the cam ring rotation angle and the fuel injection pump speed. The
fuel temperature (FT) sensor is internal the PCU. These
values are used to compare the desired values sent
from the ECM then PCU determines the injection time
r
piston position and fuel injection quantity, and actuates
timing control valve (TCV) & fuel injection solenoid
valve based on control maps in the PCU.
The timing device changes the optimum injection
timing against various engine conditions. The
pressure of the fuel fed from the feed pump is
adjusted and it acts to the timing plunger by TCV
controlled fuel pressure.
(The TCV is installed to the
fuel injection pump rear side and it is controlled by dut
y
ratio cycle from the PCU.) The timing plunger is
connected to the cam ring by a ball pin. Axial
movement of the timing plunger is transferred to the
cam ring in the form of rotational movement.




BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-289



RTW 66ESH001901
Legend
1. Drive Shaft
2. Feed Pump
3. Pump Camshaft Position (CMP) Sensor
4. Fuel Injection Pump Control Unit (PCU)
5. Distributor Head
6. Constant Pressure Valve (CPV) Holder
7. Fuel Injection Solenoid Valve
8. Constant Pressure Valve (CPV)
9. Timing Control Valve (TCV)
10. Timer
11. Radial Plunger







RTW 66ESH002001
Legend
1. Rotor Shaft
2. Radial Plunger
3. High Pressure Passage
4. Low Pressure Inlet
5. Distribution Slit
6. Valve Needle
7. Barrel
8. Annular Passage
9. Fuel Return
10. Fuel Injection Solenoid Valve
11. High Pressure Outlet
12. Diaphragm Chamber
13. Accumulator Diaphragm




BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-290 Engine Control System (4JH1)
Low Pressure Fuel Circuit Description



RTW 66ESH002101
Legend
1. Fuel Suction
2. Regulating Valve
3. Overflow Valve
4. Feed Pump
5. To Fuel Tank

The low pressure fuel circuit must supply sufficient fuel
to the high pressure fuel circuit. The main components
are the feed pump, the regulating valve and the
overflow valve.

Feed Pump



RTW 66ESH002201
Legend
1. Rotor
2. Casing Ring
3. Fuel Supply
4. Outlet
5. Chamber

6. Vane
7. Driveshaft
8. Inlet
9. Fuel Suction

The feed pump is driven by the drive shaft, performs
suction and supply of fuel. The vanes assembled in the
rotor are pressed against the inside of the casing ring
by spring forces and centrifugal force during rotation to
form chambers. W hen the vanes rotate, the volume o
f
these chambers increase when they reach recesses the
casing ring connected to the inlet port. Pressure then
decreases and fuel is drawn in. W hen the chambers
have passed the inlets and recesses, the volume
decreases and the fuel is compressed. Fuel pressure
increases until the chamber reaches the outlet, where
the fuel passes through the regulating valve to the high
pressure fuel circuit.

Regulating Valve




RTW 66ESH002301
Legend
1. To Inlet
2. Spring
3. Valve Piston
4. Port
5. From Outlet

W hen feed pump speed increases so that the delivery
pressure of the fuel delivered from the outlet exceeds
the regulating valve spring force, the plunger is pushed
upwards. Excess fuel passes through the ports and
returns to the inlet side, and the delivery pressure is
maintained within a specified range. W hen feed pump
speed decreases so that the delivery pressure
decreases, the plunger is pushed downwards by spring
force to close the port.



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-291
Overflow Valve




RTW 66ESH002401
Legend
1. Valve Holder
2. Port
3. To Fuel Tank
4. Orifice Port
5. From Fuel Tank
6. Ball Valve
7. Spring

W hen the pressure of the fuel, returned from the
distributor head, exceeds the spring force, the overflo
w
valve's ball valve is pushed up. Excess fuel presses
through the port and returns to the tank, and fuel
pressure inside the pump chamber does not exceed a
specified pressure. The flow of excess fuel serves
cooling and automatic bleeding of the fuel pump during
operation. Also the orifice port is installed to assist in
automatic air bleeding.

High Pressure Fuel Circuit Description



RTW 66ESH002501
Legend
1. Fuel Injection Pump Control Unit (PCU)
2. Distributor Head
3. Fuel Injection Solenoid Valve
4. Constant Pressure Valve (CPV)
5. Radial Plunger

In addition high pressure generating device, the high
pressure circuit also consists of fuel piping, and devices
to set the beginning of injection and fuel injection
quantity. The main components are as follows:
• High pressure generation: Radial Plunger
• Fuel distribution: Distributor Head
• Beginning of injection timing: Timing Device
• Prevention of secondary injection: Constant
Pressure Valve (CPV)


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-292 Engine Control System (4JH1)
Radial Plunger




RTW 66ESH002601
Legend
1. Radial Plunger
2. Internal Cam
3. Cam Ring
4. Rotor Shaft
5. Plunger Chamber
6. Roller Shoe
7. Roller

W hile the radial plungers assembled to the rotor shaft
rotate, they are held against the inside of the cam ring
(via the roller shoes and rollers) by fuel deliver
y
pressure from the feed pump and centrifugal force. The
radial plungers perform rotational movement as well as
internal cam induced reciprocating movement to suck in
and compress the fuel in the plunger chamber.

Distributor Head



RTW 66ESH002701
Legend
1. Rotor Shaft
2. Valve Needle
3. Constant Pressure Valve (CPV) Holder
4. High Pressure Outlet
5. Distributor Shaft
6. Barrel

The distributor head distribute the high pressure fuel
that has flowed through the rotating rotor shaft's
distributor slits and the barrel's high pressure outlets (4
cylinders: 4) to the engine cylinders via the constant
pressure valve (CPV) and the nozzle holde
r
assemblies. The fuel injection solenoid valve needle
changes the passage to the radial plunger high
pressure pump between fuel suction and fuel
compression.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Control System (4JH1) 6E-293
Fuel Injection Solenoid Valve



RTW 66ESH002801
Legend
1. Valve Seat
2. Valve Closing Direction
3. Valve Needle
4. Coil
5. Magnet
6. Magnet Anchor
7. Rotor Shaft

The fuel injection solenoid valve consists of a valve
seat, a valve needle, and a magnet anchor (a movable
iron core), a coil and a magnet. The valve needle
rotates together with the rotor shaft. W hen current
controlled by the fuel injection pump control unit (PCU)
flows to the coil, the magnet anchor and the valve
needle are pushed towards the valve seat. W hen the
valve seat is completely closed by the valve needle, the
fuel in the high pressure passage is isolated from the
low pressure passage, is compressed by the radial
plunger high pressure pump, and injected into the
engine cylinder through the nozzle holder assembly.
W hen the required injection quantity is reached, the
current to the coil is cut, the valve seat opens and
injection of fuel is completed.


Constant Pressure Valve (CPV)





RTW 66ESH002901
Legend
1. Plug
2. Ball
3. Seat
4. Valve
5. Spacer
6. Holder
7. Valve Spring
8. Oriffice
9. Ball Support
10. Spring

The constant pressure valve (CPV) consists of a holder,
a spacer, a valve spring, a valve, a seat, a ball, a ball
support, a spring and a plug. The valve is equipped with
an orifice to suppress the reflected pressure wave (the
cause of secondary injection) caused by nozzle closing
at the end of the injection and maintains a stable
pressure in the injection pipe (residual pressure) to
ensure stabilized injection timing for subsequent
injection. The valve is opened by pressurized fuel and
this high pressure fuel is delivered to the nozzle holde
r
assembly.





BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007