6E-344 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Engine Mechanical ChecksInspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression.
• Improper mechanical timing (timing gear and timing chain).
• Improper valve gap.
• Broken or weak valve springs.
• Worn camshaft lobes.
• Any excessive oil entering combustion chamber.
Additional Checks • EGR system operating correctly. Refer to EGR Control System Check in this
section.
• Excessive blow-by gasses.
Checks
Action
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ISUZU KB P190 2007
ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-345
Excessive Smoke (White Smoke)
ChecksAction
Difinition:
White smoke under load, idle or start up hot or cold.
Preliminary Check • Ensure the vehicle has an actual problem.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect the fuel quality (cetane index).
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
• Observe the Boost Pressure and Barometric Pressure (BARO) with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other.
• Crankshaft position (CKP) sensor is tight and the sensor rotor is not damaged.
Fuel System Checks • If excessive smoke is present, check for a stuck open fuel injector. Inspect for fuel
leakage into the combustion chamber.
• Fuel injectors. Remove the injectors and visually inspect.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Pilot Injection Control with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Air Intake System Checks Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
• Perform the Swirl Control Solenoid Test with a scan tool. Inspect the diaphragm valve operation when it commanded ON/ OFF.
• A worn or damaged turbocharger turbine wheel, shaft or compressor wheel. Oil leak from turbocharger. Refer to turbocharger inspection in the Engine Mechanical
section.
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ISUZU KB P190 2007
6E-346 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Engine Mechanical ChecksInspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Poor cylinder compression.
• Improper mechanical timing (timing gear and timing chain).
• Improper valve gap.
• Broken or weak valve springs.
• Worn camshaft lobes.
• Thermostat working (open stuck).
• Any excessive oil entering combustion chamber.
Electrical System Checks • Glow plug control (preheating) system operation. Refer to Glow Control System
Check in this section.
Checks
Action
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ISUZU KB P190 2007
ENGINE DIAGNOSIS (C24SE) 6-1
SECTION 6
ENGINE DIAGNOSIS
TABLE OF CONTENTS
PAGE
Engine Diagnosis .............................................................................................................. 6- 2
Hard Starting ................................................................................................................. 6- 2
Engine Compression Test Procedure ......................................................................... 6- 3
Rough Engine Idling or Engine Stalling...................................................................... 6- 4
Rough Engine Running ................................................................................................ 6- 5
Hesitation ..................................................................................................................... . 6- 6
Engine Lacks Power ..................................................................................................... 6- 7
Engine Noisy ................................................................................................................. 6 - 8
Abnormal Noise Due to Hydraulic Lash Adjustor ...................................................... 6- 9
Troubleshooting Procedure ......................................................................................... 6- 9
Abnormal Combustion ................................................................................................. 6-11
Engine Oil Consumption Excessive............................................................................ 6-12
Fuel Consumption Excessive ...................................................................................... 6-13
Oil Problems.................................................................................................................. 6-13
Engine Oil Pressure Check .......................................................................................... 6-13
Malfunction Indicator Lamp ......................................................................................... 6-14
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6-2 ENGINE DIAGNOSIS (C24SE)
Engine Diagnosis
Hard Starting
1.Starting Motor Does Not Turn Over
Trouble Shooting Procedure
Turn on headlights and starter switch.
Condition Possible cause Correction
Headlights go out or dim
considerably Battery run down or under
charged Recharge or replace battery
Terminals poorly connected Clean battery posts and terminals
and connect properly
Starting motor coil circuit shorted Overhaul or replace
Starting motor defective Overhaul or replace
2.Ignition Trouble - Starting Motor Turns Over But Engine Does Not Start
Spark Test Disconnect a high tension cable from any spark plug.
Connect the spark plug tester (use commercially
available tool), crank the engine, and check if a spark is
generated in the spark plug tester. Before cranking the
engine, make sure that the spark plug tester is properly
grounded. To avoid electrical shock, do not touch the
high tension cable while the engine is running.
Condition Possible cause Correction
Spark jumps across gap Spark plug defective Clean, adjust spark gap or replace
Spark plug wire in correct Connect properly or replace
Ignition timing incorrect Refer to Ignition System
Fuel not reaching fuel injector(s)
or engine Refer to item 3 (Trouble in fuel
system)
Valve timing incorrect Adjust
Engine lacks compression Refer to item 4 (Engine lacks
compression)
No sparking takes place Ignition coil disconnected or
broken Connect properly or replace
Electronic Ignition System with
module Replace
Poor connections in engine
harness Correct
Engine Control Module cable
disconnected or defective Correct or replace
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ENGINE DIAGNOSIS (C24SE) 6-3
3.Trouble in Fuel System Condition Possible cause Correction
Starting motor turns over and
spark occurs but engine does not
start. Fuel tank empty Fill
Water in fuel system Clean
Fuel filter clogged Replace filter
Fuel pipe clogged Clean or replace
Fuel pump defective Replace
Fuel pump circuit open Correct or replace
Evaporative Emission Control
system circuit clogged Correct or replace
Multiport Fuel Injection System
faulty Refer to "Electronic Fuel Injection"
section
4.Engine Lacks Compression
Condition Possible cause Correction
Engine lacks compression Spark plug loosely fitted or spark
plug gasket defective Tighten to specified torque or
replace gasket
Spark plug wire incorrect Connect properly or replace
Valve timing incorrect Adjust
Cylinder head gasket defective Replace gasket
Valve incorrectly seated Lap valve
Valve stem seized Replace valve and valve guide
Valve spring weakened Replace
Cylinder or piston rings worn Overhaul engine
Piston ring seized Overhaul engine.
Engine Compression Test Procedure
1. Start and run the engine until the engine
reaches normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the ignition system.
5. Remove the fuel pump relay from the relay and fuse box. 6. Engage the starter and check that the cranking
speed is approximately 300 rpm.
7. Install cylinder compression gauge into spark plug hole.
8. With the throttle valve opened fully, keep the starter engaged until the compression gauge
needle reaches the maximum level. Note the
reading.
9. Repeat the test with each cylinder. The pressure difference between the individual
cylinders should not exceed 100kPa (14.5 psi).
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ENGINE DIAGNOSIS (C24SE) 6-13
Fuel Consumption Excessive
Condition Possible cause Correction
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to "Abnormal Combustion"
Fuel cut function does not act Refer to "Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion
due to trouble in ignition system Refer to Hard Start or Abnormal
Combustion Troubleshooting
Guide
Others Engine idle speed too high Reset Idle Air Control Valve
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Oil Problems
Condition Possible cause Correction
Oil pressure too low Wrong oil in use Replace with correct engine oil
Relief valve sticking Replace
Oil pump not operating properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting
rod bearing worn Replace
Oil contamination
Wrong oil in use Replace with new engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
rebore cylinders
Oil not reaching valve system Oil passage in cylinder head or cylinder body clogged Clean or correct
Engine Oil Pressure Check
1. Check for dirt, gasoline or water in the engine
oil.
a. Check the viscosity of the oil.
b. Change the oil if the viscosity is outside the specified standard.
c. Refer to the "Maintenance and Lubrication" section of this manual.
2. Check the engine oil level. The level should fall somewhere between the
"ADD" and the "FULL" marks on the oil level
dipstick.
If the oil level does not reach the "ADD" mark on
the oil level dipstick, engine oil must be added.
3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach normal operating temperature (About 80 °C).
6. Measure the oil pressure.
Oil pressure should be:
150 kPa(21.8 psi) at idle speed.
7. Stop the engine.
8. Remove the oil pressure gauge
9. Install the oil pressure unit.
10. Start the engine and check for leaks.
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6A-2 ENGINE MECHANICAL (C24SE)
PAGE
Camshaft Housing, Check for Plance Surface ......................................................... 6A-39
Cylinder Head, Removal and Installation.................................................................. 6A-39
Cylinder Head, Disassemble and Assemble............................................................. 6A-42
Valve, Grind ................................................................................................................. 6 A-44
Valve Guide, Ream .................................................................................................... 6A-44
Valve Seating, Mill ...................................................................................................... 6A-45
Cylinder Head, Overhaul ............................................................................................ 6A-45
Flywheel....................................................................................................................... 6A-46
Starter Ring Gear(Manual Transmission) ................................................................. 6A-47
Seal Ring, Crankshaft................................................................................................. 6A-48
Seal Ring, Crankshaft Rear ........................................................................................ 6A-48
Oil Pan and Bearing Bridge ....................................................................................... 6A-49
OPERATIONS ON CRANK DRIVE ................................................................................... 6A-51 Con-Rod Bearing ........................................................................................................ 6A-51
Piston with Con-Rod................................................................................................... 6A-51
Con-Rod....................................................................................................................... 6A-52
Pistion Rings ............................................................................................................... 6A -53
OPERATIONS ON REMOVED ENGINE........................................................................... 6A-55 Crankshaft ................................................................................................................... 6 A-55
Bearing Free Play Measurement ............................................................................... 6A-57
Plastigage Method ...................................................................................................... 6A-57
Micrometer and gauge method.................................................................................. 6A-58
Bypass Valve ............................................................................................................... 6A- 59
Oil Filter ..................................................................................................................... .. 6A-59
Oil Pump ...................................................................................................................... 6A-59
Oil Pump Safety Valve ................................................................................................ 6A-60
Oil Pump(Overhaul) .................................................................................................... 6A-60
OPERATIONS ON OIL CIRCULATION ............................................................................ 6A-61 Cylinder Head Safety Valve ........................................................................................ 6A-61
OPERATIONS ON COOLING SYSYTEM ......................................................................... 6A-63 Cooling System, Check for Leakes ........................................................................... 6A-63
Cooling System, Fill Up and Bleed ............................................................................ 6A-63
Refill Coolant............................................................................................................... 6 A-64
Ignition Timing, Check ............................................................................................... 6A-64
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ISUZU KB P190 2007