Engine Control System (4JH1) 6E-255
Symptoms – Engine Controls
Symptoms – Engine Controls
Important Preliminary Inspections Before Starting
Perform Diagnostic System Check – Engine Controls
before using the symptom tables, and verify that all o
f
the following are true:
• The engine control module (ECM) and malfunction
indicator lamp (MIL) are operating correctly.
• There are no diagnostic trouble codes (DTCs)
stored, or a DTC exists but without the MIL.
• The scan tool data is within the normal operating
range. Refer to scan tool Data List in this section.
• Verify the customer concern and locate the correct
symptom in the table of contents. Inspect the items
indicated under that symptom.
Visual and Physical Inspection
Several of the symptom procedures ask for careful
visual and physical inspection. This step is extremel
y
important. The visual and physical inspection can lead
to correcting a problem without further inspections, and
can save valuable time. Ensure that:
• The ECM grounds are clean, tight, and in thei
r
proper location.
• The vacuum hoses are not split or kinked, and
properly connected. Inspect thoroughly for an
y
type of leak or restriction.
• The mass air flow (MAF) sensor is properl
y
installed. The arrows on the plastic portion of the
sensor must point toward the engine.
• The air intake ducts are not collapsed or damaged.
• There are no leaks at the MAF sensor, an
y
connections or intake manifold sealing surfaces.
• The engine harness wiring and terminals are
properly connected and are not pinched or cut.
Intermittent
Important:
Inspect for improper installation of electrical
components if an intermittent condition exists. Inspect
for aftermarket add-on electrical equipment devices,
lights, and cellular phones. Verify that no aftermarket
equipment is connected to the keyword 2000 serial data
circuit. If you cannot locate an intermittent condition, a
cellular phone communication signal may cause the
condition.
Important:
The problem may or may not turn ON the MIL or store a
DTC.
Faulty electrical connections or wiring cause most
intermittent problems. Perform a careful visual and
physical inspection of the suspect connectors for the
following conditions:
• Improperly mated connector halves
• Terminals that are not seated
• Terminals that are damaged or improperly formed
Reform or replace connector terminals in the problem
circuit in order to ensure proper contact tension.
Remove the terminal from the connector body in orde
r
to inspect for poor terminal wire connection.
Road test the vehicle with the DMM connected to the
suspected circuit. An abnormal reading that occurs
when the malfunction occurs is a good indication that
there is a malfunction in the circuit being monitored.
Use the scan tool in order to help detect intermittent
conditions. Useful features of the scan tool include the
following:
• Trigger the Snapshot feature in order to capture
and store engine parameters when the malfunction
occurs. Review this stored information in order to
see the specific running conditions that caused the
malfunction.
• Use the Plot Function on the scan tool in order to
plot selected data parameters. Review this stored
information to aid in locating an intermittent
problem. Refer to the scan tool Users Guide fo
r
more information.
Important:
If the intermittent condition exists as a start and then
stall, test for DTCs relating to the vehicle theft deterrent
system. Test for improper installation of electrical
options such as lights, cellular phones, etc.
Any of the following may cause an intermittent MIL with
no stored DTC:
• The ECM grounds are loose or dirty. Refer to
Engine Controls Schematics.
• The MIL circuit intermittently shorted to ground.
• Electrical system interference caused by a
malfunctioning relay, ECM driven solenoid, o
r
switch. The electrical component can cause a
sharp electrical surge. Normally, the problem will
occur when the malfunctioning component is
operating.
• There is an open diode across the A/C
compressor clutch or any other open diodes.
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ISUZU KB P190 2007
Engine Control System (4JH1) 6E-283
Description And Operation
Engine Control Module (ECM) Description
RTW 66ESH001201
The engine control module (ECM) is designed to
withstand normal current draws associated with vehicle
operation. Avoid overloading any circuit. W hen testing
for opens and shorts, do not ground or apply voltage to
any of the ECM circuits unless instructed to do so. In
some cases, these circuits should only be tested using
a digital multi meter (DMM). The ECM should remain
connected to the ECM harness.
The ECM is located on the floor panel. The ECM mainl
y
controls the following.
• The fuel system control
• The exhaust gas recirculation (EGR) system
control
• The preheating (glow) system control
• The A/C compressor control
• On-board diagnostics for engine control
The ECM constantly observes the information from
various sensor s. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. The ECM can
recognize operational problems, alert the driver through
the malfunction indicator lamp (MIL), and store
diagnostic trouble codes (DTCs). DTCs identify the
system faults to aid the technician in making repairs.
ECM Voltage Description
The ECM supplies a buffered voltage to various
switches and sensor s. The ECM can do this because
resistance in the ECM is so high in value that a test
lamp may not illuminate when connected to the circuit.
An ordinary shop voltmeter may not give an accurate
reading because the voltmeter input impedance is too
low. Use a 10-megaohm input impedance DMM, to
ensure accurate voltage readings. The input and/o
r
output devices in the ECM include analog-to-digital
converters, signal buffers, counters, and special drivers.
The ECM controls most components with electronic
switches which complete a ground circuit when turned
ON.
Aftermarket Electrical and Vacuum Equipment
Aftermarket or add-on electrical and vacuum equipment
is defined as any equipment which connects to the
vehicle's electrical or vacuum systems that is installed
on a vehicle after the vehicle leaves the factory. No
allowances have been made in the vehicle design fo
r
this type of equipment. No add-on vacuum equipment
should be added to this vehicle. Add-on electrical
equipment must only be connected to the vehicle's
electrical system at the battery power and ground. Add-
on electrical equipment, even when installed to these
guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such as
portable telephones and audios. Therefore, the first
step in diagnosing any powertrain fault is to eliminate all
aftermarket electrical equipment from the vehicle. Afte
r
this is done, if the fault still exists, the fault may be
diagnosed in the normal manner.
Electrostatic Discharge Damage
Electronic components used in the ECM are often
designed to carry very low voltage. Electronic
components are susceptible to damage caused b
y
electrostatic discharge. By comparison, as much as
4,000 volts may be needed for a person to feel even the
zap of a static discharge. There are several ways for a
person to become statically charged. The most
common methods of charging are by friction and
induction. •
An example of charging by friction is a person
sliding across a vehicle seat.
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ISUZU KB P190 2007
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.
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ISUZU KB P190 2007
6F – 18 EXHAUST SYSTEM
Wheel Shaft End Play
Use a dial indicator to measure the wheel shaft end play.
Apply a force of 1.2 kg (2.6 lb/11.8N) alternately to the
compressor wheel end and the turbine wheel end.
W heel Shaft End Play mm (in)
Standard Limit
0.03 - 0.06
(0.001 - 0.002) 0.09 (0.004)
150RY00034
Wheel Shaft and Bearing Clearance
Use a dial indicator to measure the wheel shaft and
bearing clearance.
W heel Shaft and Bearing Clearance mm (in)
Standard Limit
0.056 - 0.127
(0.0022 - 0.0050) 0.127 (0.0050)
150RY00036
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ENGINE MECHANICAL (4JK1/4JJ1) 6A-5
EGR system
Based upon data, including water temperature, engine
speeds or engine loads, it is controlled via Engine
Control Module (ECM) to purify exhaust by recycling
part of it.
Its main components include an EGR valve, an EGR
cooler and various sensors.
Connecting rod cap bolt
The angular tightening method of the connecting rod
cap bolt further increases reliability and durability.
Fuel rail-type electronic control injection system
The fuel rail-type electronic control injection system is
composed of a fuel supply pump that sets the target
pressure of high-pressure fuel and supply it, a fuel rail
that measures such high-pressure fuel and a fuel
injector that turns it into a fine spray and injects it. Each
is controlled via ECM based upon various signals, while
injection timing or fuel injection quantity is controlled
under every possible driving condition.
Fuel injector
The fuel injector is a 6-hole nozzle that adjusts fuel
injection quantity or injection timing by opening o
r
closing an electromagnetic valve on the head of the fuel
injector.
ECM corrects the dispersion of fuel injection quantit
y
between fuel injector according to ID code data in
memory. At the replacement of fuel injector, ID code
data should be stored in ECM.
Fuel filter with sedimenter
It is a fuel filter with sedimenter that gets rid of water by
making use of the difference in specific gravity between
light oil and water, which comes with an indicator that
notifies you that it is filled with water.
Preheating system
The preheating system consists of the ECM, the glow
relay, glow plugs and the glow indicator lamp. The
preheating system is operated when the engine coolant
temperature is low, and makes the engine easy to start.
Lubrication system
It is an oil filter with full-flow bypass, which uses a
water-cool oil cooler and oil jet to cool the piston.
Functional inspection
Inspection/adjustment of valve clearance 1. Inspection of valve clearance
• Remove the fuel injector harness assembly.
• Remove the leak off hose.
• Remove the cylinder head cover.
• Rotate the crankshaft to make the No.1
cylinder meet the compression top dead cente
r
(TDC).
RTW 76ASH001301
Legend
1. TDC
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ENGINE MECHANICAL (4JK1/4JJ1) 6A-63
LNW 21BSH020501
8. Check if the camshaft is runout.
• Place the camshaft on a V block to measure a
runout with a dial gauge.
• Rotate the camshaft slowly to measure ho
w
much the dial indicator shook. If it exceeds the
limit, replace the camshaft.
Runout of the camshaft mm (in)
Limit 0.05 (0.0020)
LNW 21BSH020601
9. Measure a camshaft journal oil clearance.
a. Measure an inside diameter of the camshaft bearing with a dial gauge.
b. Read the difference between the inside diameter of the camshaft bearing and the
diameter of the camshaft journal.
If the measured oil clearance exceeds the limit, replace the camshaft bearing.
Clearance of the journal part mm (in)
Standard 0.025
− 0.087
(0.0010 − 0.0034)
Limit 0.15 (0.0059)
LNW 21BSH054601
Reassembly
1. Install the dowel pin.
2. Install the camshaft gear. • Align the knock pin with the slot in the camshaft
gear. Use a press to install the camshaft gea
r
to the camshaft.
RTW 56ASH006601
Legend
1. Camshaft
2. Dowel Pin
3. Camshaft Gear
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ENGINE MECHANICAL (4JK1/4JJ1) 6A-89
Installation
1. Select the cylinder head gasket.
Cylinder Head Gasket Selection
Cylinder head gasket is determined by the piston head
projection from the cylinder body upper surface, in orde
r
to improve engine performance.
Three types of gasket are provided with difference o
f
thickness. Select the appropriate one out of three
grades of
gasket, according to the following procedure.
Before measurement, clear off carbon from the piston
head and cylinder body surface and also clean the
place where the gasket was installed.
011LX011
1. Use a dial indicator to measure the piston
projection amount.
2. Refer to the illustration for the piston head projection measuring positions. All measuring
positions should be as close as possible to the
cylinder block.
RTW 36ASH001701
3. Measure the points 1, 2, 3, 4 and obtain two
differences 1-2 and 3-4 on each cylinder. Calculate
the average value of the piston head projection on
each cylinder.
4. Obtain the maximum value in the four cylinders.
5. Determine the gasket grade required to the maximum value described above in accordance
with the following table.
011RY00027
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ENGINE MECHANICAL (4JK1/4JJ1) 6A-103
6. Measure the gap between the piston and the inner
diameter of the cylinder block.
Inner diameter of the cylinder block. • Use a cylinder bore dial indicator to measure
the cylinder block inner diameter both in the
thrust and radial directions in the designated
position.
• Measurement position (from the upper surface
of the cylinder block) 20 mm (0.79 in)
• Measure the cylinder block inner diamete
r
based on the average value of the actual
measurement values on 6 positions.
Cylinder block inner diameter mm (in)
95.421 – 95.450 (3.75673 – 3.75787)
LNW 61ASH006401
Legend
1. 20 mm (0.79 in)
2. Radial
3. Thrust
Piston outside diameter
• Use a micrometer to measure the outside
diameter of the piston in the right angle to the
piston pin in the designated position.
• Measurement position (from the bottom surface
of the piston) 11.00 mm (0.43 in).
RTW 56ASH023101
Legend
1. 11 mm (0.43 in)
Gap between the piston and the inner
diameter of the cylinder block mm (in)
Standard 0.082 – 0.100 (0.0032 – 0.0039)
NOTE:
If the gap exceeds the standard value, replace the
piston or rebore the cylinder block.
7. Piston replacement • The head of piston has a marking of grade A, B
or C.
• Refer to “Cylinder Block” if over size piston is
installed.
Piston Grade (Service Part) mm (in)
A 95.330 – 95.339 (3.75314 – 3.75350)
B 95.340 – 95.349 (3.75354 – 3.75389)
C 95.350 – 95.359 (3.75393 – 3.75428)
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