air condition ISUZU TF SERIES 2004 Manual Online

ENGINE MECHANICAL 6A – 61

INSPECTION AND REPAIR
Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during
inspection.




CYLINDER HEAD
Cylinder Head Lower Face Warpage
1. Use a straight edge and a feeler gauge to measure the
four sides and the two diagonals of the cylinder head lower
face.
2. The cylinder head lower surface warpage is more than the
limit, it should be replaced.


Cylinder Head Lower Face Warpage mm (in)
Standard Limit
0.05
(0.002) or less 0.20
(0.0079)


NOTE:
The cylinder head lower face cannot be reground.

Cylinder Head Height (
H) (Reference) mm (in)
Standard
91.95 – 92.05
(3.620 – 3.624)




Positive Crankcase Ventilation (PCV) Valve
1. Remove PCV valve assembly from cylinder head cover.
2. Inspect the diaphragm for broken.
3. Inspect the spring for broken or weaken.
4. If find any abnormal condition, replace the PCV valve
assembly.

011RY00012
011RY00013
011RY00014

ENGINE MECHANICAL 6A – 75










































2. Measure the piston diameter.


Piston Measuring Point mm (in)
4JA1T(L)
4JA1TC 78 (3.07)
4JH1TC 70 (2.76)


Piston Grade (Service Part) mm (in)
AX 92.949 - 92.964
(3.6549 - 3.6600)
4JA1T(L)
4JA1TC
CX 92.965 - 92.980
(3.6600 - 3.6606)
AX 95.359 - 95.374
(3.7542 - 3.7548)
4JH1TC
CX 95.375 - 95.390
(3.7548 - 3.7555)


Cylinder Liner and Piston Clearance mm (in)
4JA1T(L)
4JA1TC 0.041-0.071 (0.0016-0.0027)
4JH1TC 0.047-0.065 (0.0019-0.0026)

NOTE:
Cylinder liner kit clearances are preset. However, the
cylinder liner installation procedure may result in
slight decreases in cylinder liner clearances. Always
measure the cylinder liner clearance after installation
to be sure that it is correct.



TAPPET AND PUSH ROD
Visually inspect the tappet contact surfaces for pitting,
cracking, and other abnormal conditions. The tappet must be
replaced if any of these conditions are present.
Refer to the illustration at the left.
1. Normal contact
2. Cracking
3. Pitting
4. Irregular contact Uneven contact
5. Irregular contact One-sided contact

NOTE:
The tappet surfaces are spherical. Do not attempt to
grind them with an oil stone or similar tool in an effort
to repair the tappet. If the tappet is damaged, it must
be replaced.


015LX021
014RY00028

ENGINE COOLING 6B – 17
Inspection and Repair
Make the necessary adjustments, repairs, and part
replacements if excessive wear or damage is discovered
during inspection.


Radiator Cap
Measure the valve opening pressure of the pressurizing valve
with a radiator filler cap tester.
Replace the cap if the valve opening pressure is outside the
standard range.
Valve opening pressure kPa (psi) 93.3





122.7 (13.5





17.8)
Cap tester: 5–8840–0277–0
Adapter: 5–8840–2603–0
Check the condition of the vacuum valve in the center of the
valve seat side of the cap. If considerable rust or dirt is found,
or if the valve seat cannot be moved by hand, clean or replace
the cap.





110RS006

Valve opening vacuum kPa (psi) 1.96




4.91 (0.28




0.71)


Radiator Core
1. A bent fin may result in reduced ventilation and overheating
may occur. All bent fins must be straightened. Pay close
attention to the base of the fin when it is being straightened.
2. Remove all dust, bugs and other foreign material.

Flushing the Radiator
Thoroughly wash the inside of the radiator and the engine
coolant passages with cold water and mild detergent. Remove
all signs of scale and rust.

Cooling System Leakage Check
Use a radiator cap tester to force air into the radiator through
the filler neck at the specified pressure of 196 kPa (28.5 psi)
with a cap tester:
 Leakage from the radiator
 Leakage from the coolant pump
 Leakage from the water hoses

6B – 20 ENGINE COOLING
FAN CLUTCH WITH COOLING FAN
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear, damage or any other abnormal condition are found through
inspection.


033R300001
Visually inspect for damage, leak (sillicon grease) or other
abnormal conditions.
1. Inspection (on-vehicle)
1) Turn the fan clutch by hand when in a low temperature
condition before starting the engine, and confirm that it
can be turned readily.
2) Start the engine to warm it up until the temperature at
the fan clutch portion gets to around 80
C. Then stop
the engine and confirm that the fan clutch can be
turned with considerable effort (clutch torque) when
turned by hand.
If the fan clutch rotates more readily, however, this
indicates that the silicone grease is leaking internally.
Replace the fan clutch with a new one.



033RY00011
2. Inspection (in unit)
Warm up the bimetal of the fan clutch by using the heat
gun until the temperature gets to about 80
C when
measured with the thermistor. Then confirm that the fan
clutch can be turned with considerable effort (clutch
torque).
If the fan clutch retates more readily at this time, this
indicates that the silicone grease is leaking internally.
Replace the fan clutch with a new one.

FUEL SYSTEM 6C – 7
INJECTION PUMP


RTW46CLF000201

4JA1T(L):
A Bosch Distributor Type Injection Pump is used. A single reciprocating/revolving plunger delivers the fuel uniformly
to the injection nozzles, regardless of the number of cylinders.
The governor, the injection timer, and the feed pump are all contained in the injection pump housing. The injection
pump is compact, light weight, and provides reliable high-speed operation.
The vacuum-type fast idle actuator increases the engine idling speed to provide the additional power required to
operate the air conditioner.
Fast idler diaphragm movement is caused by changes in the negative pressure created by the engine’s vacuum
pump.
The diaphragm motion is transferred to the injection pump control lever to increase or decrease the idling speed.

4JA1TC/4JH1TC:
The Bosch VP44 injection pump is electronically controlled. The pump controller combine to injection pump.
Signals from the pump controller are sent to the engine control module (ECM). In response to these signals, the
ECM selects the optimum fuel injection timing and volume for the existing driving conditions.

6D – 16 ENGINE ELECTRICAL



RTW46DSH000901

















Vacuum Pump
Vacuum Pump Disassembly
1. Remove the center plate from the vacuum pump
housing.
2. Remove the vacuum pump rotor and the vanes from
the housing.


Inspection
Vacuum Pump Housing and Center Plate
Inspect the vacuum pump housing and the center plate for
excessive wear, abrasion, and scoring.
If any of these conditions are present, the vacuum pump
housing and center plate must be replaced.



Vane
Inspect the vanes for excessive wear and damage.
Replace all four vanes if either of these conditions are
present.
Never replace only one vane.


Rotor
1. Inspect the rotor for excessive wear, abrasion, and
scoring.
Pay particular attention to the internal spline.
Replace the rotor if any of these conditions are
present.
2. Inspect the generator rotor shaft splines for backlash.
Replace the rotor if backlash is present.














RTW46DSH005201
Check Value
1. Carefully force the valve from the “B” side as shown in
the illustration.
The valve must move smoothly.
If it does not, the check valve must be replaced.
2. Apply compressed air to the “A” side.
Air Pressure kPa (kg/cm
2/psi)
98 - 490 (1-5/14 – 71)

Check for air leakage from the check valve.
If there is air leakage, the valve must be replaced.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–9
ABBREVIATION CHARTS
A bbreviations A ppellation
A/C Air conditioner
A/T Automatic transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CAN Controller Area Network
CEL Check engine lamp
CKP Crankshaft position sensor
DLC Data link connector
DTC Diagnosis trouble code
DVM Digital voltage meter
ECM Engine control module
ECT Engine coolant temperature
EEPROM Electrically erasable & programmable read only memory
EGR Ex haust gas recirculation
EVRV Electric vacuum regulating valve
GND Ground
GRY Gray
IAT Intake air temperature
IG Ignition
M/T Manual transmission
MAB High pressure solenoid valve cutoff (German abbreviation)
MAF Mass air flow
MIL Malfunction indicator lamp
OBD On-board diagnostic
ORN Orange
PNK Pink
RED Red
PSG Pump control unit (German abbreviation)
SW Switch
TCM Transmission control module
TCV Timing control valve
TDC Top dead center
TPS Throttle position sensor
VCC Voltage constunt control
VIO Violet
VSS Vehicle speed sensor
WHT Whi te
YEL Yellow

6E–64 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)
The engine control module (ECM) is located flower
panel just under the passenger's seat.
The fuel quantity and injection timing related functions
are controlled by the pump control unit (PSG).
The engine control module (ECM) performs the
following functions.
Control of the ex haust gas re-circulation (EGR)
Control of the quick on start (QOS) glow control
system
Control of the A/C compressor
Ex ecution of the immobilizer function
Pump Control Unit (PSG) & Data Exchange
Between Control Module
The radial plunger distributor type injection pump uses
two control modules to ex ecute full control of the enginemanagement system.
Engine Control Module (ECM)
Pump Control Unit (PSG) = Pumpen Steuer Great
(German)
The pump control unit (PSG) receives signals from the
sensors inside the pump to determine the cam ring
rotation angle, the pump speed and the fuel
temperature .
These values are then compared to the desired values
sent by the engine control module (ECM) such as the
desired injection timing and the desired fuel injection
quantity.
The engine control module (ECM) processes all engine
data and data regarding the surrounding environment
received from ex ternal sensors to perform any engine
side adjustments.
Maps for both are encoded in both control units. The
control units input circuit process sensor data.
A Microprocessor then determines the operating
conditions and calculates set values for optimum
running.
The interchange of data between the engine control
module (ECM) and the pump control unit (PSG) is
perfumed via a CAN-bus system. The abbreviation CAN
stands for Controller Area Network. By having two
separate control modules, the high pressure solenoid
valve. This prevents the discharge of any disturbing
signals.
The information ex change between the two control
modules takes place via two means.
Via analogue signal leads
Via the CAN-bus
The analogue signal leads are used to ex change the
following information.
Engine speed signal (ECM terminal 91)
Pump Speed (ECM terminal 105)
Fuel Cutoff solenoid valve signal (MAB signal) (ECM
terminal 105)
The engine speed signal is sent from the ECM to PSG
based on the input from the crank shaft position (CKP)
sensor.
The analogue CKP sensor signal is converted by the
ECM into a square wave signal.
The fuel cutoff solenoid valve signal is also referred to
as MAB signal.
MAB in this case, refers to the German abbreviation
Magnet ventil ABschaltung that stands for high pressure
solenoid v alv e cut off.
The MAB signal wire is used for two purposes.
-As a reference for the engine control module (ECM) for
the pump speed (back up for the CKP sensor).
-To turn Off the engine.
Sel f Dia gn osis / Interfa ce / Si gn al
To High Pressure Solenoid
Engine Speed
Injection Timing
Accelerator Pedal
Injection Quantity
In ta ke Air Temperat ure
Response Signal
Ma ss Air Flow
Additional Signal
Others

Additional Operations To Timing Control Valve (TCV)
Engin e
Con trol
Modu le
(ECM) Cam Rin g Rota tiona l Angle
Fuel Temper atu re
High Pressure
Solenoid Valve
Pump
Con tr ol Fuel Inject ion
Unit (Mechanical)
(PSG)

Ti m i n
g Devi ce

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–77
Diagnostic Thought Process
As you follow a diagnostic plan, every box on the
Strategy Based Diagnostics chart requires you to use
the diagnostic thought process. This method of thinking
optimizes your diagnosis in the following ways:
Improves your understanding and definition of the
customer complaint
Saves time by avoiding testing and/or replacing good
parts
Allows you to look at the problem from different
perspectives
Guides you to determine what level of understanding
about system operation is needed:
–Owner’s manual level
–Service manual level
–In-depth (engineering) level
–Owner’s manual level
–Service manual level
–In-depth (engineering) level
1. Verify the Complaint
What you should do
To verify the customer complaint, you need to know the
correct (normal) operating behavior of the system and
verify that the customer complaint is a valid failure of the
system.
The following information will help you verify the
complaint:
WHAT the vehicle model/options are
WHAT aftermarket and dealer-installed accessories
exist
WHAT related system(s) operate properly
WHEN the problem occurs
WHERE the problem occurs
HOW the problem occurs
HOW LONG the condition has ex isted (and if the
system ever worked correctly)
HOW OFTEN the problem occurs
Whether the severity of the problem has increased,
decreased or stayed the same
What resources you should use
Whenever possible, you should use the following
resources to assist you in verifying the complaint:
Service manual Theory or Circuit Description
sections
Service manual “System Performance Check”
Owner manual operational description
Technician ex perience
Identical vehicle for comparisonCircuit testing tools
Vehicle road tests
Complaint check sheet
Contact with the customer
2. Perform Preliminary Checks
NOTE: An estimated 10 percent of successful vehicle
repairs are diagnosed with this step!
What you should do
You perform preliminary checks for several reasons:
To detect if the cause of the complaint is VISUALLY
OBVIOUS
To identify parts of the system that work correctly
To accumulate enough data to correctly and
accurately search for a ISUZU Service Bulletin on
ISUZU Web site.
The initial checks may vary depending on the
complex ity of the system and may include the following
actions:
Operate the suspect system
Make a visual inspection of harness routing and
accessible/visible power and ground circuits
Check for blown fuses
Make a visual inspection for separated connectors
Make a visual inspection of connectors (includes
checking terminals for damage and tightness)
Check for any DTCs stored by the on-board
computers
Sense unusual noises, smells, vibrations or
mov ements
Investigate the vehicle service history (call other
dealerships, if appropriate)
What resources you should use
Whenever appropriate, you should use the following
resources for assistance in performing preliminary
checks:
Tech II or other technical equipment for viewing DTCs
Service manual information:
–Component locations
–Harness routing
–Wiring schematics
–Procedures for viewing DTCs
Dealership service history file
Vehicle road test
Identical vehicle or system for comparison

6E–78 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
3. Check Bulletins and
Troubleshooting Hints
NOTE: As estimated 30 percent of successful vehicle
repairs are diagnosed with this step!
What you should do
You should have enough information gained from
preliminary checks to accurately search for a bulletin
and other related service information. Some service
manual sections provide troubleshooting hints that
match symptoms with specific complaints.
What resources you should use
You should use the following resources for assistance in
checking for bulletins and troubleshooting hints:
Printed bulletins
Access ISUZU Bulletin Web site.
Videotapes
Service manual
4. Perform Service Manual
Diagnostic Checks
What you should do
The “System Checks” in most service manual sections
and in most cells of section 8A (electrical) provide you
with:
A systematic approach to narrowing down the
possible causes of a system fault
Direction to specific diagnostic procedures in the
service manual
Assistance to identify what systems work correctly
What resources you should use
Whenever possible, you should use the following
resources to perform service manual checks:
Service manual
Technical equipment (for viewing DTCs and
analyzing data)
Digital multimeter and circuit testing tools
Other tools as needed
5a and 5b. Perform Service Manual
Diagnostic Procedures
NOTE: An estimated 40 percent of successful vehicle
repairs are diagnosed with these steps!
What you should do
When directed by service manual diagnostic checks,
you must then carefully and accurately perform the
steps of diagnostic procedures to locate the fault relatedto the customer complaint.
What resources you should use
Whenever appropriate, you should use the following
resources to perform service manual diagnostic
procedures:
Service manual
Technical equipment (for analyzing diagnostic data)
Digital multimeter and circuit testing tools
Essential and special tools
5c. Technician Self Diagnoses
When there is no DTC stored and no matching
symptom for the condition identified in the service
manual, you must begin with a thorough understanding
of how the system(s) operates. Efficient use of the
service manual combined with you ex perience and a
good process of elimination will result in accurate
diagnosis of the condition.
What you should do
Step 1: Identify and understand the suspect
circuit(s)
Having completed steps 1 through 4 of the Strategy
Based Diagnostics chart, you should have enough
information to identify the system(s) or sub-system(s)
involved. Using the service manual, you should
determine and investigate the following circuit
characteristics:
Electrical:
–How is the circuit powered (power distribution
charts and/or fuse block details)?
–How is the circuit grounded (ground distribution
charts)?
–How is the circuit controlled or sensed (theory of
operation):
–If it is a switched circuit, is it normally open or
normally closed?
–Is the power switched or is the ground
switched?
–Is it a variable resistance circuit (ECT sensor
or TP sensor, for ex ample)?
–Is it a signal generating device (MAF sensor of
VSS, for example)?
–Does it rely on some mechanical/vacuum
device to operate?
Physical:
–Where are the circuit components (component
locators and wire harness routing diagrams):
–Are there areas where wires could be chafed
or pinched (brackets or frames)?
–Are there areas subjected to ex treme
temperatures?