Page 1505 of 3573

SERVICE INFORMATION 00 Ð 5
Idling improperly adjusted Adjust the idling Idling system
Checkpoint Possible cause Correction
Defective fast idling speed control device Repair or replace the fast idling
speed control device Fast idling speed
control device
Accelerator control system improperly
adjustedAdjust the accelerator control
system Accelerator control
system
2. UNSTABLE IDLING
4. QUICK-ON START SYSTEM (QOS III)
PREPARATION
1. Disconnect the thermoswitch connector.
2. Determine whether or not the glow plugs are receiving power.
a) Make sure that the starter switch is "OFF"
b) Connect a voltmeter between one of the glow plugs and the cylinder wall.
c) Move the starter switch to the "ON" position.
The voltmeter needle will show the souse voltage (12V) if the glow plugs are receiving power.
If the voltmeter needle does not move, the glow plugs are not receiving power.
3. Perform the troubleshooting procedure.
1.
2.
3.Replace the fusible link wire
Replace the indicator light fuse
Replace the indicator light bulb Glow plug indicator
light does not turn
on.Defective Fusible link wire
Broken indicator light fuse
Defective indicator light bulb
1.
2.
3.
4.Replace the fusible link wire
Replace or Repair glow plug relay
connector
Replace or Repair glow plug
connector
Replace or Repair quick-on start
timer connector Preheating system
does not workDefective Fusible link wire shorted
Defective glow plug relay connector
Defective glow plug connector
Defective quick-on start timer connector
1.
2.
3.Replace thermo sensor or repair
wiring harness.
Replace glow plug
Replace timer unit Preheating time to
long or to shortDefective thermo sensor include
defective wiring harness
Defective glow plug
Defective timer unit
Page 1506 of 3573

00 Ð 6 SERVICE INFORMATION
Checkpoint Possible cause Correction
Injection timing improperly adjusted Adjust the injection timing
Insufficient injection volume Adjust the injection volume
Defective idle spring Replace the idle spring
Defective governor lever operation Repair or replace the governor
lever
Regulator valve improperly adjustment Adjust or replace the regulator valve
Broken plunger spring Replace the plunger spring
Worn plunger Replace the plunger assembly
Worn cam disc Replace the cam disc
Valve clearance improperly adjusted Adjust the valve clearance Valve clearance
Blown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking between
the valve and the valve seatReplace the related parts Compression
pressure
Fuel system leakage or blockage Repair or replace the fuel system Fuel system
Air in the fuel system Bleed the air from the fuel system
Water particles in the fuel system Change the fuel
Clogged fuel filter element Replace the fuel filter element or
the fuel filter cartridge Fuel filter
Defective fuel feed pump Repair or replace the fuel feed pump Fuel feed pump
Injection nozzle sticking Replace the injection nozzle Injection nozzle
Injection nozzle injection starting pressure
too low
Improper spray conditionAdjust or replace the injection
nozzle
Defective delivery valve resulting in fuel
drippage after fuel injectionReplace the delivery valve Injection pump
Page 1507 of 3573

SERVICE INFORMATION 00 Ð 7
3. INSUFFICIENT POWER
Clogged air cleaner element Clean or replace the air cleaner
element Air cleaner
Checkpoint Possible cause Correction
Water particle in the fuel Replace fuel Fuel
Clogged fuel filter element Replace the fuel filter element or
the fuel filter cartridge Fuel filter
Defective fuel feed pump Repair or replace the fuel feed pump Fuel feed pump
Injection nozzle sticking Replace the injection nozzle Injection nozzle
Injection nozzle injection starting pressure
too low
Improper spray conditionAdjust or replace the injectionn
nozzle
Fuel injection pipes damaged or obstructed Replace the fuel injection pipes Fuel injection pipes
Defective regulating valve Repair or replace the regulating
valve Injection pump
Defective delivery valve Replace the delivery valve
Defective timer Repair or replace the timer
Worn cam disk Replace the cam disk
Improper control lever operation Adjust or replace the control lever
Defective injection timing Adjust the injection timing
Repair or replace the injection pump
timer
Weak governor spring Replace the governor spring
Worn plunger Replace the plunger saaembly
Worn cam disk Replace the cam disk
Page 1508 of 3573
00 Ð 8 SERVICE INFORMATION
Checkpoint Possible cause Correction
Booster compensator pipe broken or
crackedReplace the booster compensator
pipe Turbocharger
Exhaust gas leakage from the exhaust
system
Air leakage from the intake systemRepair or replace the related parts
Defective waste gate Repair or replace the waste gare
Defective turbocharger assembly Replace the turbocharger assembly
Blown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking between the valve and
valve seatReplace the related parts Compression
pressure
Valve clearance improperly adjusted Adjust the valve clearance Valve clearance
Valve spring weak or broken Replace the valve spring Valve spring
Exhaust pipe clogged Clean the exhaust pipe Exhaust system
Open and improperly set adjusting screw
sealAdjust and reseal the adjusting
screw Full load adjusting
screw seal
Page 1509 of 3573

SERVICE INFORMATION 00 Ð 9
4. EXCESSIVE FUEL CONSUMPTION
5. EXCESSIVE OIL CONSUMPTION
Checkpoint Possible cause Correction
Engine oil Engine oil unsuitable
Too mauch engine oilReplace the engine oil
Correct the engine oil level
Oil seal and gasket Oil leakage from the oilseal and/or the
gasketReplace the oil seal and/or the
gasket
Air breather Clogged air breather Clean the air breather
Intake and exhaust
valveWorn valve stems and valve guides Replace the intake and exhaust
valves and the valve springs
Checkpoint Possible cause Correction
Fuel system Fuel leakage Repair or replace the fuel system
related parts
Air cleaner Clogged air cleaner element Clean or replace the air cleaner
element
Idling speed Poorly adjusted idling speed Adjust the idling speed
Injection nozzle Injection nozzle injection starting pressure
too low
Improper spray condition Adjust or replace the injection
nozzle
Fuel injection timing Fuel injection timing improperly Adjust the fuel injection timing
Injection pump Defective Delivery valve resulting is fuel
drippage after fuel injectionReplace the delivery valve
Turbocharger Air leakage from the turbocharger intake
sideRepair the turbocharger intake side
Defective turbocharger assembly Replace the turbocharger assembly
Valve clearance Valve clearance improperly adjusted Adjust the valve clearance
Compression
pressureBlown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking between the valve and
valve seatReplace the related parts
Valve spring Valve spring weak or broken Replace the valve spring
Page 1510 of 3573

00 Ð 10 SERVICE INFORMATION
6. OVERHEATING
7. WHITE EXHAUST SMOKE
Checkpoint Possible cause Correction
Fuel Water particles in the fuel Replace the fuel
Fuel injection timing Delayed fuel injection timing Adjust the fuel injection timing
Compression
pressureBlown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking between the valve and
valve seatReplace the related parts
Turbocharger Defective turbocharger Replace the turbocharger
Inlet and exhaust
valves
Valves sealsDefective valve seales.
Worn valves stems and valve guidesReplace the valve seales, the valves,
and the valve guides
Checkpoint Possible cause Correction
Cooling water Insufficient cooling water Replace the cooling water
Fan clutch Oil leakage from the fan clutch Replace the fan clutch
Fan belt Fan belt loose or cracked causing slippage Replace the fan belt
Radiator Defective radiator cap or clogged radiator
coreReplace the radiator cap or clean the
radiator core
Water pump Defective water pump Repair or replace the water pump
Cylinder head and
cylinder body sealing
capDefective searing cap resulting in water
leakageReplace the sealing cap
Thermostat Defective thermostat Replace the thermostat
Cooling system Cooling system clogged by foreign
materialClean the foreign material from the
cooling system
Fuel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing
Page 1511 of 3573

SERVICE INFORMATION 00 Ð 11
8. DARK EXHAUST SMOKE
Checkpoint Possible cause Correction
Air cleaner Clogged air cleaner element Clean or replace the air cleaner
element
Injection nozzle Injection nozzle injection starting pressure
too low
Improper spray conditionAdjust or replace the injection
nozzle
Fuel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing
Injection pump Defective Delivery valve resulting is fuel
drippage after fuel injectionReplace the delivery valve
Excessive injection volume Adjust the injection volume
9. OIL PRESSURE DOES NOT RISE
Checkpoint Possible cause Correction
Engine oil Improper viscosity engine oil. Insufficient
engine oilReplace the engine oil
Correct the engine oil volume
Oil pressure gauge
or unit
Oil pressure indicator
lightDefective oil pressure gauge or unit
Defective indicator lightRepair or replace the oil pressure
gauge or unit
Replace the indicator light
Oil filter Clogged oil filter element Replace the oil filter element or the
oil filter cartridge
Relief valve and by-
pass valveRelief valve sticking and/or weak by-pass
valve springReplace the relief valve and/or the
by-pass valve spring
Oil pump Clogged oil pump strainer Clean the oil pump strainer
Worn oil pump related parts Replace the oil pump related parts
Rocker arm shaft Worn rocker arm bushing Replace the rocker arm bushing
Camshaft Worn camshaft and camshaft bearing Replace the camshaft and the
camshaft bearing
Crankshaft and
bearingsWorn crankshaft and bearings Replace the crankshaft and/or the
bearings
Page 1512 of 3573

00 Ð 12 SERVICE INFORMATION
10. ABNORMAL ENGINE NOISE
Checkpoint Possible cause Correction
Fuel Fuel unsuitable Replace the fuel
1. ENGINE KNOCKING
2. GAS LEAKAGE NOISE
Exhaust pipes Loosely connected exhaust pipes. Broken
exhaust pipesTighten the exhaust pipe
connections
Replace the exhaust pipes Check to see that the engine has been thoroughly warmed up before begining the troubleshooting
procedure.
Fuel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing
Injection nozzle Improper injection nozzle starting pressure
and spray conditionAdjust or replace the injection
nozzle
Compression
pressureBlown out head gasket
Broken piston ringReplace the head gasket or the
piston ring
Injection nozzles
and/or glow plugsLoose injection nozzles and/or glow plugs Replace the washers
Tighten the injection nozzles and/or
the glow plugs
Exhaust manifold Loosely connected exhaust manifold and/or
glow plugsTighten the exhaust manifold
connections
Cylinder head gasket Damaged cylinder head gasket Replace the cylinder head gasket
3. CONTINUOUS NOISE
Fan belt Loose fan belt Readjust the fan belt tension
Cooling fan Loose coling fan Retighten the cooling fan
Water pump bearing Worn or damaged water pump bearing Replace the water pump bearing
Alternator or vacuum
pumpDefective alternator or vacuum pump Repair or replace the alternator or
the vacuum pump
Valve clearance Clearance improperly adjust Adjust the valve clearance