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Isuzu KB P190. Manual - part 503

6-12 ENGINE DIAGNOSIS (C24SE)

Engine Oil Consumption Excessive

Condition Possible

cause Correction

Oil leaking

Oil pan drain plug loose

Retighten or replace gasket

Oil pan setting bolds loosened

Retighten

Oil pan gasket broken

Replace gasket

Front cover retaining bolts loose
or gasket broken

Retighten or replace gasket

Head cover retaining bolts loose
or gasket broken

Retighten or replace gasket

Oil filter adapter cracked

Replace

Oil filter attaching bolt loose or
rubber gasket broken

Retighten or replace oil filter

Crankshaft front or rear oil seal
defective

Replace oil seal

Oil pressure unit loose or broken

Retighten or replace

Blow-by gas hose broken

Replace hose

Engine/Transmission

coupling

area

Replace oil seal

Oil leaking into combustion
chambers due to poor seal in
valve system

Valve stem oil seal defective

Replace

Valve stem or valve guide worn

Replace valve and valve guide

Oil leaking into combustion
chambers due to poor seal in
cylinder parts

Cylinders and pistons worn
excessively

Rebore cylinder and replace
pistons and others

Piston ring gaps incorrectly
positioned

Correct

Piston rings set with wrong side
up

Correct

Piston rings sticking

Rebore cylinder and replace
pistons and others

Piston ring and ring groove worn

Replace pistons and others

Return ports in oil rings clogged

Clean piston and replace rings

Crank case ventilation, Positive
Crankcase Ventilation System
malfunctioning

Positive Crankcase Ventilation
Hose clogged

Clean

Others

Improper oil viscosity

Use oil of recommended S.A.E.
viscosity

Continuous high speed driving
and or severe usage such as
trailer towing

Continuous high speed operation
and or severe usage will normally
cause increased oil consumption

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.

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

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 ..................................................................................................................... 6A-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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