2007 ISUZU KB P190 check engine

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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ISUZU KB P190 2007

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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ISUZU KB P190 2007

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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6-6 ENGINE DIAGNOSIS (C24SE)
Hesitation
Condition Possible cause Correction
Hesitation on acceleration Throttle Position Sensor
adjustment incorrect Replace throttle valve assembly

Throttle Position Sensor circuit
open or shorted Correct or replace

Excessive play in accelerator
linkage Adjust or replace

Manifold Absolute Pressure
(MAP) Sensor circuit open or
shorted Correct or replace

MAP Sensor defective Replace
Intake Air Temperature (IAT)
Sensor circuit open or shorted Correct or replace

Knock Sensor (KS) Circuit open or
shorted Correct or replace
KS
defective Replace
KS Module circuits open or
shorted Correct or replace

KS Module defective Replace
IAT Sensor defective Replace
Hesitation at high speeds
(Fuel pressure too low) Fuel tank strainer clogged Clean or replace

Fuel pipe clogged Clean or replace
Fuel filter clogged Replace
Defective fuel pump system Check and replace
Fuel Pressure Control Valve
leaking Replace
Hesitation at high speeds
(Fuel injector not working
normally) Power supply or ground circuit for
Multiport Fuel Injection System
shorted or open Check and correct or replace

Cable of Multiport Fuel Injection
System disconnected or defective Correct or replace
Hesitation at high speeds
Engine Control Module defective Replace
Throttle Position Sensor circuit
open or shorted Correct or replace

Throttle Position Sensor defective Replace
Engine Coolant Temperature
Sensor circuit open or shorted Correct or replace

Engine Coolant Temperature
Sensor defective Replace

MAP Sensor cable open or
shorted Correct or replace

MAP Sensor defective Replace
IAT Sensor circuit open or shorted Correct or replace
IAT Sensor defective Replace
KS Circuit open or shorted Correct or replace
KS defective Replace
KS Module circuit open or shorted Correct or replace
KS Module defective Replace
Throttle valve not wide opened Check and correct or replace
Air Cleaner Filter clogged Replace filter element
Power supply voltage too low Check and correct or replace

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ISUZU KB P190 2007

ENGINE DIAGNOSIS (C24SE) 6-9
Abnormal Noise Due to Hydraulic Lash Adjuster
Should abnormal noise due to the hydraulic lash
adjuster trouble be heard immediately after the engine
is started, inspect as follows:
Condition Possible cause Correction
Abnormal noise is heard Air contaminated Bleed
HLA is spongy Check ball valve broken Repair
Safety valve in cylinder head
broken Replace
Valve clearance is not zero HLA inside stick
Replace HLA assembly

Troubleshooting Procedure
Short out each spark plug in sequence using insulated
spark plug wire removers. Locate cylinder with
defective bearing by listening for abnormal noise that
stops when spark plug is shorted out.
Condition Possible cause Correction
Noise from connecting rods or
from connecting rod bearings
(Faulty connecting rods or
connecting rod bearings usually
make an abnormal noise slightly
higher than the crank bearing
noise, which becomes more
evident when engine is
accelerated) Bearing or crankshaft pin worn Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing
Crankpin out of round Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing
Connecting rod bent Correct or replace
Connecting rod bearing seized Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing

Troubleshooting Procedure
Abnormal noise stops when the spark plug on the
cylinder with defective parts is shorted out.
Condition Possible cause Correction
Piston and cylinder
(Faulty piston or cylinder usually
makes a combined mechanical
thumping noise which increases
when engine is suddenly
accelerated but diminishes
gradually as the engine warms up) Piston clearance increased due to
cylinder wear Replace piston and cylinder body

Piston seized Replace piston and cylinder body
Piston ring broken Replace piston and cylinder body
Piston defective Replace pistons and others


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ISUZU KB P190 2007

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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6-14 ENGINE DIAGNOSIS (C24SE)
Malfunction Indicator Lamp
The instrument panel "CHECK ENGINE" Malfunction
Indicator lamp (MIL) illuminates by self diagnostic
system when the system checks the starting of
engine, or senses malfunctions.
Condition Possible cause Correction
"CHECK ENGINE" MIL does not
illuminate at the starting of engine Bulb defective Replace

MIL circuit open Correct or replace
Command signal circuit to operate
self diagnostic system shorted Correct or replace

Engine Control Module (ECM)
cable loosely connected,
disconnected or defective Correct or replace
ECM
defective Replace
“CHECK ENGINE” MIL
illuminates, and stays on Deterioration heated oxygen
sensor of internal element Replace

Heated oxygen sensor connector
terminal improper contact
(If applicable) Reconnect properly

Heated oxygen sensor lead wire
shorted (If applicable) Correct

Heated oxygen sensor circuit
open (If applicable) Correct or replace

Deterioration engine coolant
temperature sensor of internal
element Replace

Engine coolant temperature
sensor connector terminal
improper contact Reconnect properly

Engine coolant temperature
sensor lead wire shorted Correct

Engine coolant temperature
sensor circuit open Correct or replace

Throttle position sensor open or
shorted circuits Correct or replace

Deterioration of crankshaft
position sensor Replace

Crankshaft position sensor circuit
open or shorted Correct or replace

Vehicle speed sensor circuit open Correct or replace
Manifold absolute pressure sensor
circuit open or shorted Correct or replace

Intake air temperature sensor
circuit open or shorted Correct or replace

Fuel injector circuit open or shorted Correct or replace
ECM driver transistor defective Replace EPROM or ECM
Malfunctioning of ECM RAM
(Random Access Memory) or
Malfunctioning of ECM PROM
(Programmed Read Only Memory) Replace EPROM or ECM


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ISUZU KB P190 2007

ENGINE MECHANICAL (C24SE) 6A-1
SECTION 6A
ENGINE MECHANICAL
TABLE OF CONTENTS
PAGE
General Description ........................................................................................................ 6A- 4
ENGINE PICTORIAL .................................................................................................... 6A- 6
Main Data and Specification ........................................................................................... 6A-11 CRANKCASE VENTILATION SYSTEM ....................................................................... 6A-16
ENGINE ASSEMBLY & LOOSE PARTS ..................................................................... 6A-17
OPERATIONS ON ENGINE AGGREGATES.................................................................... 6A-18 Engine Damping Blocks(Engine without Transmission) ........................................ 6A-18
Toothed Belt and Timing Check ............................................................................... 6A-21
Toothed Belt Tension, Adjust .................................................................................... 6A-23
Toothed Belt, Replace ................................................................................................ 6A-24
OPERATIONS ON INSTALLED ENGINE ......................................................................... 6A-26 Gasket, Exhaust Manifold, Cylinder Head ................................................................ 6A-26
Gasket, Intake Manifold, Cylinder Head .................................................................... 6A-26
Seal Ring, Camshaft Housing, Timing Side.............................................................. 6A-27
Seal Ring, Thermostat Housing, Cylinder Head....................................................... 6A-27
Seal Ring - Front Camshaft Housing, Replace ......................................................... 6A-28
Toother Belt Rear Cover............................................................................................. 6A-30
Toother Belt Tension Roller ....................................................................................... 6A-31
COMPONENT PARTS ...................................................................................................... 6A-32 Cylinder Head .............................................................................................................. 6A- 32
Hydraulic Valve Lifter ................................................................................................. 6A-33
OPERATIONS ON CYLINDER HEAD AND CAMSHAFT HOUSING ............................... 6A-34 Camshaft ..................................................................................................................... 6 A-34
Camshaft Housing Removal and Installation ........................................................... 6A-35
Cylinder Head .............................................................................................................. 6A- 35
Hydraulic Valve Lifers, Replace................................................................................. 6A-37
Camshaft Housing, Replace ...................................................................................... 6A-37

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ISUZU KB P190 2007