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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ISUZU KB P190 2007
6-4 ENGINE DIAGNOSIS (C24SE)
Rough Engine Idling or Engine Stalling
Condition Possible cause Correction
Trouble in fuel injection system Idle air control valve defective Replace
Throttle shutting off incomplete Correct or replace
Throttle position sensor circuit
open or shorted Correct or replace
Fuel injector circuits open or
shorted Correct or replace
Fuel injectors damaged Replace
Fuel pump relay defective Replace
Manifold Absolute Pressure
Sensor cable disconnected or
broken Correct or replace
Manifold Absolute Pressure
Sensor defective Replace
Engine Coolant Temperature
Sensor cable disconnected or
broken Correct or replace
Engine Coolant Temperature
Sensor defective Replace
Intake Air Temperature sensor
cable disconnected or broken Correct or replace
Intake Air Temperature sensor
defective Replace
Knock Sensor (KS) circuits open
or shorted Correct or replace
KS
defective Replace
KS Module circuits open or
ground Correct or replace
KS Module defective Replace
Vehicle Speed Sensor circuit open
or shorted Correct or replace
Vehicle Speed Sensor defective Replace
Trouble in emission control
system Engine Control Module defective Replace
Canister purge solenoid circuit
open Correct
Canister purge solenoid defective Replace
Evaporative Emission Canister
Purge control valve defective Replace
Trouble in ignition system Refer to Hard Start
Troubleshooting Guide
Others Engine lacks compression Refer to Hard Start
Troubleshooting Guide
Valve incorrectly seated Lap valve
Air Cleaner Filter clogged Replace filter element
Valve timing incorrect Readjust
Idle air control valve broken Replace
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ISUZU KB P190 2007
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) 6-7
Engine Lacks Power
Condition Possible cause Correction
Trouble in fuel system Fuel Pressure Control Valve not
working normally Replace
Fuel injector clogged Clean or replace
Fuel pipe clogged Clean
Fuel filter clogged or fouled Replace
Fuel pump drive circuit not
working normally Correct or replace
Fuel tank not sufficiently breathing
due to clogged Evaporative
Emission Control System circuit Clean or replace
Water in fuel system Clean
Inferior quality fuel in fuel system Use fuel of specified octane rating
Engine Control Module supplied
poor voltage Correct circuit
Throttle Position Sensor cable
disconnected or broken Correct or replace
Throttle Position Sensor defective Replace
Manifold Absolute Pressure
Sensor not working normally Replace
Intake Air Temperature sensor not
working normally Replace
Engine Coolant Temperature
Sensor circuit open or shorted Correct or replace
Engine Coolant Temperature
Sensor defective Replace
Engine Control Module defective Replace
Trouble in intake or exhaust
system Air Cleaner Filter clogged Replace filter element
Air duct kicked or flattened Correct or replace
Ignition failure
- Refer to Hard Start
Troubleshooting Guide
Heat range of spark plug
inadequate Install spark plugs of adequate
heat range
Electronic Ignition System with
module Replace
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ISUZU KB P190 2007
ENGINE DIAGNOSIS (C24SE) 6-11
Abnormal Combustion
Condition Possible cause Correction
Trouble in fuel injection system Fuel pressure control valve
defective Replace
Fuel filter clogged Replace
Fuel pump clogged Clean or replace
Fuel tank or fuel pipe clogged Clean or replace
Fuel injector clogged Clean or replace
Fuel pump relay defective Replace
Power supply cable for fuel pump
loosely connected or defective Reconnect, correct or replace
Manifold Absolute Pressure
Sensor circuit open or shorted Correct or replace
Manifold Absolute Pressure
Sensor defective Replace
Engine Coolant Temperature
(ECT) Sensor circuit open or
shorted Correct or replace
ECT Sensor defective Replace
Throttle Position Sensor
adjustment incorrect Reconnect
Throttle Position Sensor defective Replace
Throttle Position Sensor
connector loosely connected Reconnect
Vehicle Speed Sensor cable
loosely connected or defective Correct or replace
Vehicle Speed Sensor loosely
fixed Fix tightly
Vehicle Speed Sensor in wrong
contact or defective Replace
Engine Control Module cable
loosely connected or defective Correct or replace
Trouble in emission control
system Heated Oxygen Sensor circuit
open (If applicable) Correct or replace
Heated Oxygen Sensor defective
(If applicable) Replace
Signal vacuum hose loosely fitted
or defective Correct or replace
ECT Sensor circuit open or
shorted Correct or replace
ECT Sensor defective Replace
Evaporative Emission Control
system (If applicable) Refer to Section 6E
Trouble in ignition system
- Refer to "Engine Lacks Power"
Trouble in cylinder head parts Carbon deposits in combustion
chamber Remove carbon
Carbon deposit on valve, valve
seat and valve guide Remove carbon
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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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ISUZU KB P190 2007
ENGINE MECHANICAL (C24SE) 6A-3
PAGE
ENGINE EXTERNAL PARTS ........................................................................................... 6A-65 Radiator ....................................................................................................................... 6A-65
Thermostat .................................................................................................................. 6A -66
Water Pump ................................................................................................................. 6A- 66
Coating sealing surfaces with Silicone Grease ....................................................... 6A-67
Alternator ..................................................................................................................... 6A-67
Starter ........................................................................................................................ .. 6A-67
V-belt Tension of Alternator ....................................................................................... 6A-68
FUEL INJECTION SYSTEM ............................................................................................. 6A-70 Map Sensor ................................................................................................................. 6A- 70
Pressure Regulator..................................................................................................... 6A-70
ECM (Engine Control Module) ................................................................................... 6A-70
ECT............................................................................................................................ ... 6A-71
Idle Air Control(IAC) Valve ......................................................................................... 6A-71
Ignition Coil ................................................................................................................. 6A-71
Crank Position Sensor ............................................................................................... 6A-72
FUEL INJECTOR .............................................................................................................. 6A- 73
Knock Sensor.............................................................................................................. 6A-7 3
Oxygen Sensor............................................................................................................ 6A-74
Throttle Valve Position Sensor .................................................................................. 6A-74
Acclelerator Pedal and Cable .................................................................................... 6A-74
Air Cleaner Filter ......................................................................................................... 6A- 75
Spark Plug Thread ...................................................................................................... 6A-76
TECHNICAL DATA ........................................................................................................... 6A-77
Recommended Troque Values .................................................................................. 6A-88
SPECIAL SERVICE TOOL ............................................................................................... 6A-89
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ISUZU KB P190 2007
ENGINE MECHANICAL (C24SE) 6A-11
Main Data and Specifications
Engine - General C24SE
Engine type Four-cycle, water cooled cross-flow with single over head
camshaft
Micro-computer control, fuel injection
Combustion chamber type (Volume) Hemispherical (43.3cm3)
Timing train system Belt drive
No. of cylinders-bore × stroke mm (in) 4-87.5 ×100.0 (3.44 ×3.93)
Bore Spacing(C/L to C/L) 93.0 mm (3.66 in)
Firing Order 1-3-4-2
Bore×Stroke mm (in) 87.5 ×100.0 (3.44 ×3.93)
Total piston displacement cm3 (in3) 2,405(146.80)
Combustion Chamber Volume 43.3cm3
No. of piston ring Compression ring: 2, Oil ring: 1
Compression pressure kg/cm2 (psi/pa) 12.2-16.3 (174-232/1200-1600)
Ignition timing (BTDC) No adjustment
Idling speed: rpm(W O/AC,W /AC) A/C off 825
Valve clearances (At cold)
Intake mm (in) 0 (0) (Hydraulic valve lash adjustment)
Exhaust mm (in) 0 (0) ( " )
Open at (BTDC) deg 17°30’
Close at (ABDC) deg 76°30’
Exhaust valves
Open at (BBDC) deg 58°30’
Close at (ATDC) deg 35°30’
Ignition system Fully transistorized battery ignition
Distributor type Not applicable, Electronic Spark Timing control
Distributor advance type Not applicable, Electronic Spark Timing control
Spark plug type RN9YC4
Spark plug gap mm (in) 1.0--1.1 (0.039--0.043)
Lubrication system
Lubricating method Fully flow pressure circulation
Special engine oil (API grade) SE, SF, SG or SH grade
Oil pressure kg/cm2 (psi/Pa) rpm 4-4.6 (56.9-65.4/400-450)
Oil pump type Gear
Oil filter type Cartridge full flow
Oil capacity lit. (US/UK gal.) 4.25
Cooling system
Radiator type Corrugated fin with reserve tank
Coolant capacity lit.
(US/UK gal.) 2.3 (0.66/0.55)
W ater pump type
Centrifugal
Thermostat W ax pellet with jiggle hole
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ISUZU KB P190 2007