Isuzu Diesel Engine 4JA1 Workshop Manual Section 6

249 Pages·2000·3.88 MB·English

WORKSHOP MANUAL
TBR SERIES
ENGINE
(cid:215)
4JA1-NA 4JA1-L MODELS
SECTION 6
NOTICE
Before using this Workshop Manual to assist you in performing vehicle
service and maintenance operations, it is recommended that you
carefully read and thoroughly understand the information contained in
Section - 0A under the headings "GENERAL REPAIR
INSTRUCTIONS" and "HOW TO USE THIS MANUAL".
All material contained in this Manual is based on the latest product
information available at the time of publication.
All rights are reserved to make changes at any time without prior
notice.
Applicable Model : TBR54
This manual is applicable to 2000 year model and later vehicles.
THIS MANUAL INCLUDES FOLLOWING SECTIONS
SECTION CONTENTS
6 Troubleshooting
6A Engine Mechanical
6B Engine Cooling
6C Fuel System
6D Engine Electrical
6F Exhaust System
TROUBLESHOOTING 6-1
SECTION 6
TROUBLESHOOTING
TABLE OF CONTENTS
PAGE
Hard Starting....................................................................................................................... 6- 3
Starter Inoperative......................................................................................................... 6- 3
Starter Motor Operates But Engine Does Not Turn Over ........................................... 6- 4
Engine Turns Over But Does Not Start........................................................................ 6- 5
Unstable Idling.................................................................................................................... 6- 8
Insufficient Power............................................................................................................... 6-11
Excessive Fuel Consumption............................................................................................ 6-15
Excessive Oil Consumption............................................................................................... 6-17
Overheating......................................................................................................................... 6-18
White Exhaust Smoke........................................................................................................ 6-20
Dark Exhaust Smoke.......................................................................................................... 6-21
Oil Pressure Does Not Rise............................................................................................... 6-22
Abnormal Engine Noise..................................................................................................... 6-24
Turbocharger...................................................................................................................... 6-27
6-2 TROUBLESHOOTING
Refer to the following troubleshooting charts to quickly pinpoint and repair engine problems.
1.This Section is divided into ten Sub-Sections.
Refer to the Table of Contents.
2.Each troubleshooting chart has three headings arranged from left to right:
Example:
3.Easily checked areas are presented at the beginning of the troubleshooting chart. Procedures become more
complex as the chart progresses.
4.It is suggested that you work from the beginning of the troubleshooting chart. Do not start from the middle.
5.It is possible that a seemingly apparent engine problem is not related to the engine.
For example, the engine may appear to have insufficient power. This could be caused by dragging brakes or a
slipping clutch instead of an engine malfunction.
Refer to the other troubleshooting charts if required.
6.Optional equipment and variations are included in the troubleshooting charts.
If the vehicle you are servicing is not equipped with a particular option or variation noted in the "Checkpoint"
frame, disregard the frame and move on to the next one.
TROUBLESHOOTING 6-3
1. HARD STARTING
1. STARTER INOPERATIVE
Checkpoint Trouble Cause Countermeasure
Loose battery cable terminals
NG Clean and/or retighten the
Battery Poor connections due to
battery cable terminals
rusting
NG
Battery discharged or weak Recharge or replace the battery
NG
Fan belt loose or broken Adjust or replace the fan belt
OK
NG
Main fuse Main fuse shorted Replace the main fuse
OK
NG Defective starter switch or Replace the starter switch or
Starter switch
starter relay the starter relay
OK
NG Defective magnetic switch or Repair or replace the magnetic
Starter motor
starter relay switch
NG Repair or replace the starter
Defective starter motor
motor
6-4 TROUBLESHOOTING
2. STARTER MOTOR OPERATES BUT ENGINE DOES NOT TURN OVER
Checkpoint Trouble Cause Countermeasure
Loose battery cable terminals
NG Clean and/or retighten the
Battery Poor connections due to
battery cable terminals
rusting
NG
Battery discharged or weak Recharge or replace the battery
NG
Fan belt loose or broken Adjust or replace the fan belt
OK
NG
Starter motor Defective pinion gear Replace the pinion gear
NG Repair or replace the magnetic
Defective magnetic switch
switch
NG Brush wear Replace the brush and/or the
Weak brush spring brush spring
OK
NG Piston, crank bearing seizure, Repair or replace the related
Engine
or other damage parts
TROUBLESHOOTING 6-5
3. ENGINE TURNS OVER BUT DOES NOT START
Checkpoint Trouble Cause Countermeasure
NG Defective fuel cut solenoid Replace the fuel cut solenoid
Engine stop mechanism
valve valve
FUEL IS NOT BEING DELIVERED TO THE INJECTION PUMP
NG
Fuel Fuel tank is empty Fill the fuel tank
OK
Repair or replace the fuel lines
NG Clogged or damaged fuel lines
Fuel piping Retighten the fuel line
Loose fuel line connections
connections
OK
NG Fuel filter overflow valve does Repair or replace the fuel filter
Fuel filter
not close overflow valve
NG Replace the fuel filter element
Clogged fuel filter element
or the fuel filter cartridge
OK
NG Bleed the air from the fuel
Fuel system Air in the fuel system
system
OK
NG Repair or replace the feed
Fuel feed pump Defective feed pump
pump
6-6 TROUBLESHOOTING
FUEL IS BEING DELIVERED TO THE INJECTION PUMP
Checkpoint Trouble Cause Countermeasure
NG
Fuel Use the wrong fuel Use the correct fuel
NG
Water particles in the fuel Change the fuel
OK
NG Bleed the air from the fuel
Fuel system Air in the injection pump
system
OK
NG
Injection nozzle Injection nozzle sticking Replace the injection nozzle
NG Injection nozzle injection Adjust or replace the injection
starting pressure too low
nozzle
Improper spray condition
OK
NG Defective fuel injection nozzle
Injection pump resulting in fuel drippage after Replace the delivery valve
fuel injection
NG Injection pump plunger worn or Replace the injection pump
stuck plunger assembly
Continued on the next page
TROUBLESHOOTING 6-7
Checkpoint Trouble Cause Countermeasure
Continued from the previous page
NG Injection pump drive shaft Replace the injection pump
Injection pump
seizure or other damage drive shaft
NG Injection pump governor spring Replace the injection pump
seizure governor spring