Isuzu 4JB1, 4JB1T, 4JB1TC, 4JG2 Service Information

SERVICE INFORM

ATION 00 – 3

1.

HARD STARTING

1. STARTER INOPERATIVE
Checkpoint Possible cause Correction

Loos

e battery cable terminal poor

connections due to rusting

Clean and/or retighten the battery
cable terminal

Batter

y discharged or weak Recharge or replace the battery

Battery

F

an belt loose or broken Adjust or replace the fan belt

F

usible link Fusible link shorted Replace the fusible link

Star

ter switch Defective starter switch or starter relay Replace the starter switch or the

Starter relay

Def

ective magnetic switch or starter relay Repair or replace the magnetic switch

Starter m

otor

Defective starter motor Repair or replace the starter motor

2. STARTER MOTOR OPERATES BUT ENGINE DOES NOT TURN OVER

Loos

e battery cable terminal Clean and/or retighten the battery

cable terminal

Poor

connections due to rusting Recharge or replace the battery

Batter

y discharged or weak Recharge or replace the battery

Battery

F

an belt loose or broken Adjust or replace the fan belt

Def

ective pinion gear Replace the pinion gear

Def

ective magnetic switch Repair or replace the magnetic switch

Star

ter

Brush wear, Weak brush spring Replace the brush and/or the brush

spring

Engine

Piston, crank bearing seizure, or other
damage

Repair or replace the related parts

00 – 4 SERVICE INF

ORMATION

3. ENGINE TURNS OVER BUT DOES NOT START
Checkpoint Possible cause Correction

Engine s

top

mechanism

Defective fuel cut solenoid valve Replace the fuel cut solenoid valve

FUEL IS NOT BEING DELIVERED TO THE INJECTION PUMP

F

uel Fuel tank is empty Fill the fuel tank

F

uel piping Clogged or damaged fuel lines. Loose fuel

line connection

Repair or replace the fuel lines
Retighten the fuel line connection

F

uel filter overflow valve does not close Repair or replace the fuel filter

overflow valve

F

uel filter

Clogged fuel filter element Replace the fuel filter element or the

filter cartridge

F

uel system Air in the fuel system Bleed the air from the fuel system

F

uel feed pump Defective feed pump Repair or replace the feed pump

FUEL IS BEING DELIVERED TO THE INJECTION PUMP

Us

e of the wrong fuel Use the correct fuel

W

ater particles in the fuel Change the fuel

F

uel

Fuel system

Air in the injection pump Bleed the air from the fuel system
Inj

ection nozzle sticking

Inj

ection nozzle

Injection nozzle injection starting pressure
too low
Improper spray condition

Adjust or replace the injection nozzle

Def

ective fuel injection nozzle resulting in the

fuel drippage after fuel injection

Replace the delivery valve

Def

ective injection pump control rack

operation

Repair or replace the injection pump
control rack

Inj

ection pump plunger worn or stuck Replace the injection pump plunger

assembly

Inj

ection pump drive shaft seizure or other

damage

Replace the injection drive shaft

Inj

ection pump

Injection pump governor spring seizure Replace the injection pump governor

spring

SERVICE INFORM

ATION 00 – 5

4. QUICK-ON START SYSTEM

PREPARAT

ION

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.

GLOW PLUGS ARE RECEIVING POWER

Checkpoint Possible cause Correction

G

low plug indicator

light does not turn on

Defective indicator light bulb Replace the indicator light bulb

Q

uick-on start timer Defective quick-on start timer Replace the quick-on start timer

G

low plug indicator
light turns on the 0.3
seconds

Defective quick-on start timer Replace the quick-on start timer

Return the s

tarter switch to the “ON” position
from the “START” position after the engine
starts if the glow plug relay remains on less
than 14 seconds, the quick-on start timer is
defective

Replace the quick-on start timer

G

low plug indicator
light turns on for 3.5
seconds

Move the starter switch from the “OFF”
position to the “ON” position if the glow plug
relay remains on less than 14 seconds, the
quick-on start timer is defective

Replace the quick-on start timer

T

hermoswitch Defective thermoswitch Replace the thermoswitch

G

low plug continuity No glow plug continuity Replace the glow plugs

GLOW PLUGS ARE NOT RECEIVING POWER

G

low plug indicator
light does not turn on

Broken indicator light fuse Replace the fuse

Q

uick-on start timer Defective quick-on start timer Replace the quick-on start timer

00 – 6 SERVICE INF

ORMATION

GLOW PLUGS ARE NOT RECEIVING POWER (Cont’d)

Checkpoint Possible cause Correction

Def

ective glow plug relay
The glow plug relay does not turn on after the
starter switch is moved from the “OFF”
position to the “ON” position

Replace the glow plug relay

Defective quick-on start timer Replace the quick-on start timer
Defective glow plug relay wiring harness Repair or replace the wiring harness

G

low plug indicator
light turns on for 3.5
seconds

Defective fusible link or wiring harness
The glow plug relay turns on when the starter
switch is moved from the “OFF” position to
the “ON” position

Replace the fusible link or the wiring
harness

2.

UNSTABLE IDLING

Checkpoint Possible cause Correction

Idling s

ystem Idling improperly adjusted Adjust the idling

F

ast idling speed Defective fast idling speed control device Repair or replace the fast idling speed

control device

A

ccelerator control

system

Accelerator control system improperly
adjusted

Adjust the accelerator control system

F

uel system leakage or blockage Repair or replace the fuel system

Air

in the fuel system Bleed the air from the fuel system

F

uel system

Water particles in the fuel system Change the fuel

F

uel filter Clogged fuel filter element Replace the fuel filter element or the

fuel filter cartridge

F

uel feed pump Defective fuel feed pump Repair or replace the fuel feed pump

Inj

ection nozzle sticking Replace the injection nozzle

Inj

ection nozzle

Injection nozzle injection starting pressure
too low
Improper spray condition

Adjust or replace the injection nozzle

Inj

ection pump Defective delivery valve resulting in fuel

drippage after fuel injection

Replace the delivery valve

SERVICE INFORM

ATION 00 – 7

Checkpoint Possible cause Correction

Inj

ection timing improperly adjusted Adjust the injection timing

Ins

ufficient injection volume Adjust the injection volume

Def

ective idle spring Replace the idle spring

Def

ective governor lever operation Repair or replace the governor lever

Regulator

valve improperly adjustment Adjust or replace the regulator valve

Br

oken plunger spring Replace the plunger spring

W

orn plunger Replace the plunger assembly

Inj

ection pump

(Cont’d)

Worn cam disc Replace the cam disc

Valve c

learance Valve clearance improperly adjusted Adjust the valve clearance

Com

pression pressure Blown out cylinder head gasket. Worn

cylinder liner.
Piston ring sticking

Replace the related parts

3. INSUFFICIENT POWER

Checkpoint Possible cause Correction

Air

cleaner Clogged air cleaner element Clean or replace the air cleaner

element

F

uel Water particle in the fuel Replace fuel

F

uel filter Clogged fuel filter element Replace the fuel filter element or the

fuel filter cartridge

F

uel feed pump Defective fuel feed pump Repair or replace the fuel feed pump

Inj

ection nozzle sticking Replace the injection nozzle

Inj

ection nozzle

Injection nozzle injection starting pressure
too low
Improper spray condition

Adjust or replace the injection nozzle

F

uel injection pipes Fuel injection pipes damaged or obstructed Replace the fuel injection pipes

00 – 8 SERVICE INF

ORMATION

Checkpoint Possible cause Correction

Def

ective regulating valve Repair or replace the regulating valve

Def

ective delivery valve Replace the delivery valve

Def

ective timer Repair or replace the timer

W

orn cam disc Replace the cam disc

Im

proper control lever operation Adjust or replace the control lever

Def

ective injection timing Adjust the injection timing

Repair or replace the injection pump
timer

W

eak governor spring Replace the governor spring

Inj

ection pump

Worn plunger Replace the plunger assembly

Com

pression pressure Blown out cylinder head gasket. Worn

cylinder liner.
Piston ring sticking

Replace the related parts

Valve c

learance Valve clearance improperly adjusted Adjust the valve clearance

Valve s

pring Valve spring weak or broken Replace the valve spring

Ex

haust system Exhaust pipe clogged Clean the exhaust pipe

F

ull load adjusting

screw seal

Open and improperly set adjusting screw
seal

Adjust and reseal the adjusting screw

SERVICE INFORM

ATION 00 – 9

4. EXCESSIVE FUEL CONSUM

PTION

Checkpoint Possible cause Correction

F

uel 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 s

peed Poorly adjusted idling speed Adjust the idling speed

Inj

ection nozzle Injection nozzle injection starting pressure

too low
Improper spray condition

Adjust or replace the injection nozzle

F

uel injection timing Fuel injection timing improperly Adjust the fuel injection timing

Inj

ection pump Defective Delivery valve resulting is fuel

drippage after fuel injection

Replace the delivery valve

Valve c

learance Valve clearance improperly adjusted Adjust the valve clearance

Com

pression pressure Blown out cylinder head gasket. Worn

cylinder liner.
Piston ring sticking

Replace the related parts

Valve s

pring Valve spring weak or broken Replace the valve spring

5. EXCESSIVE OIL CONSUM

PTION

Checkpoint Possible cause Correction

Engine oil

Engine oil unsuitable
Too much engine oil

Replace the engine oil
Correct the engine oil level

O

il seal and gasket Oil leakage from the oil seal and/or the

gasket

Replace the oil seal and/or the gasket

Air

breather Clogged air breather Clean the air breather

Intak

e and exhaust

valve

Worn valve stems and valve guides Replace the intake and exhaust

valves and the valve guides

00 – 10 SERVICE INF

ORMATION

6.

OVERHEATING

Checkpoint Possible cause Correction

Cooling w

ater Insufficient cooling water Replenish the cooling water

F

an clutch Oil leakage from the fan clutch Replace the fan clutch

F

an belt Fan belt loose or cracked causing slippage Replace the fan belt

Radiator

Defective radiator cap or clogged radiator
core

Replace the radiator cap or clean the
radiator core

W

ater pump Defective water pump Repair or replace the water pump

Cy

linder head and
cylinder body sealing
cap

Defective sealing cap resulting in water
leakage

Replace the sealing cap

T

hermostat Defective thermostat Replace the thermostat

Cooling s

ystem Cooling system clogged by foreign material Clean the foreign material from the

cooling system

F

uel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing

7. WHITE EXHA

UST SMOKE

Checkpoint Possible cause Correction

Cooling w

ater Insufficient cooling water Replace the cooling water

F

uel Water particles in the fuel Replace the fuel

F

uel injection timing Delayed fuel injection timing Adjust the fuel injection timing

Com

pression pressure Blown out cylinder head gasket. Worn

cylinder liner.
Piston ring sticking

Replace the related parts

Inlet and ex

haust valve

Valves seals

Defective valve seals.
Worn valves stems and valve guides

Replace the valve seals, the valves,
and the valve guides

SERVICE INF

ORMATION 00 – 11

8. DA

RK EXHAUST SMOKE

Checkpoint Possible cause Correction

Air

cleaner Clogged air cleaner element Clean or replace the air cleaner

element

Inj

ection nozzle Injection nozzle injection starting pressure

too low
Improper spray condition

Adjust or replace the injection nozzle

F

uel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing

Def

ective delivery valve resulting in fuel

drippage after fuel injection

Replace the delivery valve

Inj

ection pump

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 oil

Replace the engine oil
Correct the engine oil volume

O

il pressure gauge or
unit
Oil pressure indicator
light

Defective oil pressure gauge or unit
Defective indicator light

Repair or replace the oil pressure
gauge or unit
Replace the indicator light

O

il filter Clogged oil filter element Replace the oil filter element or the oil

filter cartridge

Relief

valve and by-

pass valve

Relief valve sticking and/or weak by-pass
valve spring

Replace the relief valve and/or the by­pass valve spring

Clogged oil pum

p strainer Clean the oil pump strainer

O

il pump

Worn oil pump related parts Replace the oil pump related parts

Roc

ker arm shaft Worn rocker arm bushing Replace the rocker arm bushing

Cam

shaft Worn camshaft and camshaft bearing Replace the camshaft and the

camshaft bearing

Cr

ankshaft and

bearings

Worn crankshaft and bearings Replace the crankshaft and/or the

bearings

00 – 12 SERVICE INF

ORMATION

10.

ABNORMAL ENGINE NOISE

1. ENGINE KNOCKING

Chec

k to see that the engine has been thoroughly warmed up before beginning the troubleshooting procedure.

Checkpoint Possible cause Correction

F

uel Fuel unsuitable Replace the fuel

F

uel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing

Inj

ection nozzle Improper injection nozzle starting pressure

and spray condition

Adjust or replace the injection nozzle

Com

pression pressure Blown out head gasket

Broken piston ring

Replace the head gasket or the piston
ring

2. GAS LEAKAGE NOISE

Ex

haust pipes Loosely connected exhaust pipes. Broken

exhaust pipes

Tighten the exhaust pipe connections
Replace the exhaust pipes

Inj

ection nozzles

and/or glow plugs

Loose injection nozzles and/or glow plugs Replace the washers

Tighten the injection nozzles and/or
the glow plugs

Ex

haust manifold Loosely connected exhaust manifold and/or

glow plugs

Tighten the exhaust manifold
connections

Cy

linder head gasket Damaged cylinder head gasket Replace the cylinder head gasket

3. CONTINUOUS NOISE

F

an belt Loose fan belt Readjust the fan belt tension

Cooling f

an Loose cooling fan Retighten the cooling fan

W

ater pump bearing Worn or damaged water pump bearing Replace the water pump bearing

G

enerator or vacuum
pump

Defective generator or vacuum pump Repair or replace the generator or the

vacuum pump

Valve c

learance Clearance improperly adjust Adjust the valve clearances

SERVICE INF

ORMATION 00 – 13

4. SLAPPING NOISE
Checkpoint Possible cause Correction

Valve c

learance Valve clearance improperly adjusted Adjust the valve clearance

Roc

ker arm Damaged rocker arm Replace the rocker arm

F

lywheel Loose flywheel bolts Retighten the flywheel bolts

Cr

ankshaft and thrust

bearings

Worn or damaged crankshaft and/or thrust
bearings

Replace the crankshaft and/or the
thrust bearings

Cr

ankshaft and
connecting rod
bearings

Worn or damaged crankshaft and/or
connecting rod bearings

Replace the crankshaft and/or the
connecting rod bearings

Connec

ting rod

bushing and piston pin

Worn or damaged connecting rod bushing
and piston pin

Replace the connecting rod bushing
and/or the piston pin

Pis

ton and cylinder

liner

Worn or damaged piston and cylinder liner. Replace the piston and the cylinder

liner.

00 – 14 SERVICE INF

ORMATION

11. ENGINE COOLING TROUBLE

Checkpoint Possible cause Correction

Low

coolant level Replenish

T

hermo unit faulty Replace

F

aulty thermostat Replace

F

aulty coolant unit Repair or replace

Clogged r

adiator Clean or replace

F

aulty radiator cap Replace

Low

engine oil level or use of improper

engine oil

Replenish or change oil
Replenish

Dam

aged cylinder head gasket Replace

Clogged ex

haust system Clean exhaust system or replace

faulty parts

Loos

e fan belt Adjust

E

xcessive fuel injected Adjust

Engine over

heating

Improper injection timing Adjust

Engine over

cooling Faulty thermostat Replace

F

aulty thermostat Replace

T

oo long engine

warm-up time

Thermo unit faulty Replace

SERVICE INF

ORMATION 00 – 15

12. ENGINE ELECTRICA

L PART TROUBLE

STAR

TER DOES NOT RUN

C

HECK BATTERY

CHA

RGING FAILURE OR LIFE

C

HECK BATTERY

CONNE

CTION FAILURE

CLE

AN BATTERY TERMINALS, AND RECONNECT

T

URN ON HEAD LAMP AND STARTER S WITCH

HE

AD LAMP DOES NOT COME ON

OR IT IS EXTREMELY DARK

a)

LACK OF BATTERY CHARGI NG
b) SHORT-CIRCUIT IN STARTER OIL
c) FAULTY STARTER PARTS

a)

DISCONNECT STARTER CI RCUIT
b) DISCONNECT STARTER COIL
c) FAULTY STARTER SWITCH

B

ATTERY IS NORMAL

CHE

CK TERMINAL CONNECTION

CHECK STARTER OR STARTER SWITCH

T

ERMINAL CONNECTION IS NORMAL

F

AILURE

R

EPAIR OR REPLACE

HE

AD LAMP ILLUMINATES

00 – 16 SERVICE INF

ORMATION

F

AULTY MESHING OF PINION AND RING GEAR

C

HECK IF BATTERY VOLTAGE IS PRESENT AT
MAGNETIC SWITCH TERMINAL “S” WHEN
STARTER SWITCH IS TURNED TO “START (ST)”

YES

EX

TREME WEAR OF
PINION AND RING
GEAR

R

EPAIR OR REPLACE
STARTER, REPLACE
RING GEAR

OR

NO

UNDE

R THIS CONDITION, CHECK IF VOLTAGE
OF CONNECTOR 3BW ON MAGNET IC SWITCH
OF RESTART RELAY IS NORMAL

YES NO

DI

SCONNECTION OR
FAULTY CONNECTION
BETWEEN STARTER
SWITCH AND MAGNETIC
SWITCH

C

HECK IF VOLTAGE IS
PRESENT AT WIRING
CONNECTOR 3BW ON
STARTER SWITCH OF
RESTART RELAY

STAR

TER SLIDING
RESISTANCE IS
LARGE

R

EPAIR OR REPLACE

STARTER

FAU

LTY CONNECTION OF

STARTER SWITCH

DI

SCONNECTION OR
FAULTY CONNECTION
BETWEEN STARTER
SWITCH AND BATTERY

R

EPLACE STARTER

SWITCH

R

EPAIR

YES NO

RE

PAIR

SERVICE INF

ORMATION 00 – 17

M

AGNETIC SWITCH DOES NOT OPERATE THOUGH

STARTER SWITCH IS TURNED TO “START (ST)”

C

HECK IF VOLTAGE IS PRESENT AT MAGNETIC
SWITCH TERMINAL “S” WHEN STARTER SWITCH IS
TURNED TO “START (ST)”

YE

S

NO

CHE

CK GROUND CABLE

YE

S

YES

YES NO

R

EPAIR

OR

PIN

ION
SLIDING
PART DOES
NOT MOVE

M

AGNETIC SWITCH
OR COIL IS
DISCONNECTED OR
BURNED OUT

R

EPAIR OR REPLACE STARTER

CHE

CK IF INDICATOR LAMP ON

METER COMES ON NORMALLY

YES NO

DI

SCONNECTION OR
FAULTY CONNECTION
BETWEEN BATTERY
AND STARTER SWITCH

CHE

CK CONTINUITY
STARTER SWITCH AND
MAGNETIC SWITCH
TERMINAL “S”

C

HECK STARTER

RELAY

F

AULTY CONNECTION

OR STARTER SWITCH

R

EPAIR

CHE

CK CLUTCH
START

R

EPLACE STARTER

SWITCH

00 – 18 SERVICE INF

ORMATION

PIN

ION MESHES WITH RING GEAR BUT

ENGINE DOES NOT RUN

CHE

CK GROUND CABLE

YES

NO

R

EPAIR OR REPLACE

GROUND CABLE

F

AULTY CONNECTION
OF BRUSH AND
COMMUTATOR

B

URNED-OUT
MAGNETIC
STARTER SWITCH

R

EPAIR OR REPLACE STARTER

DI

SCONNECTION
OR DAMAGE OF
FIELD COIL

DI

SCONNECTION
OR DAMAGED OF
ARMATURE COIL

SL

IP OF
PINION
CLUTCH

SERVICE INF

ORMATION 00 – 19

M

AGNETIC SWITCH CONTACTS ARE
FUSED AND NOT MOVED, OR A
RETURN SPRING IS BROKEN OR
DETERIORATED

NO

STAR

TER DOES NOT STOP THOUGH STARTER

SWITCH IS RETURNED TO “ON” FROM “START”

R

EPLACE STARTER SWITCH

D

ISCONNECTED STARTER SWITCH WIRING CONNECTOR, AND CHECK STARTER SWITCH OPERATION.

KEY
POSITION

BATTERY

B1

IGNITION

IG1

BATTERYB2ACCESSORIES

ACC

IGNITION

IG2

STARTER

ST
LOCK
OFF
AC

C
ON
STAR

T

TH

ERE MUST BE NO CONTINUITY EXCEPT ABOVE LINES.

YES

R

EPLACE MAGNETIC SWITCH

00 – 20 SERVICE INF

ORMATION

13.

TURBOCHARGER

1) ENGINE HAS LESS THAN NORMAL POWER

Checkpoi

nt Trouble Cause Countermeasure

Air

cleaner

R

estricted

Clean or

replace

Intak

e pipe and hose

R

estricted

Clean or

replace

Com

pressor/Intake manifold

Loos

e (Leaking)

Repair

Ex

haust manifold/turbine inlet

Loos

e (Leaking)

Repair

Ex

haust piping and silencers

R

estricted

Clean or

replace

Air

breather

R

estricted

Clean or

replace

Boos

t compensator

(Injection pump)

Def

ective

Repair

or replace

Continued on the nex

t page

OKOK

OK

OK

OK

OK

OK

NG

NG

NG

NG

NG

NG

NG

SERVICE INF

ORMATION 00 – 21

Checkpoi

nt Trouble Cause Countermeasure

Com

pressor wheel

Im

pact damage

Replac

e

T

urbine wheel

Im

pact damage

Replac

e

Car

bon build-up

Replac

e

Rotating as

sembly

Dr

agging or seized

Replac

e

Continued f

rom the previous page

OKOK

OK

NG

NG

NG

NG

OK

00 – 22 SERVICE INF

ORMATION

2) BLUE OR BLACK SMOKE

Checkpoi

nt Trouble Cause Countermeasure

Air

cleaner or intercooler

R

estricted

Clean, r

epair, or replace

T

urbocharger oil seal

Leak

age

Replac

e

T

urbocharger oil drain pipe

R

estricted

Repair

or replace

Air

breather

R

estricted

Clean

Boos

t compensator

(Injection pump)

Def

ective

Repair

or replace

Com

pressor wheel

Im

pact damage

Replac

e

T

urbine wheel

Im

pact damage

Replac

e

Continued on the nex

t page

OKOK

OK

OK

OK

OK

OK

NG

NG

NG

NG

NG

NG

NG

SERVICE INF

ORMATION 00 – 23

Checkpoi

nt Trouble Cause Countermeasure

Center

housing oil drain passage

R

estricted

Clean or

replace

Continued f

rom the previous page

NG

OK

00 – 24 SERVICE INF

ORMATION

3) EXCESSIVE OIL CONSUMPTION

Checkpoi

nt Trouble Cause Countermeasure

Air

breather

R

estricted

Clean

Boos

t compensator

(Injection pump)

Def

ective

Repair

or replace

T

urbocharger oil seal

Leak

age

Replac

e

T

urbocharger oil drain pipe

R

estricted

Clean or

replace

T

urbine wheel

Im

pact damage

Replac

e

Com

pressor wheel

Im

pact damage

Replac

e

O

il pressure

E

xcessive

Repair

Continued on the nex

t page

OKOK

OK

OK

OK

OK

OK

NG

NG

NG

NG

NG

NG

NG

SERVICE INF

ORMATION 00 – 25

Checkpoi

nt Trouble Cause Countermeasure

Center

housing oil drain passage

R

estricted

Clean or

replace

Continued f

rom the previous page

NG

OK

00 – 26 SERVICE INF

ORMATION

4) EXCESSIVE TURBOCHARGER NOISE

Checkpoi

nt Trouble Cause Countermeasure

Intak

e and exhaust

system joints

R

estricted

Repair

Intak

e and exhaust system

gaskets

Dam

aged

Replac

e

T

urbocharger rotating parts

Rough r

otation

Replac

e

Rubbing agains

t housing

Repair

or replace

Dam

aged

Replac

e

Rubbing agains

t housing

Repair

or replace

Dam

aged

Replac

e

Continued on the nex

t page

OKOK

OK

OK

NG

NG

NG

NG

NG

NG

NG

Com

pressor wheel

T

urbine wheel

Car

bon deposits

Clean or

replace

NG

SERVICE INF

ORMATION 00 – 27

Checkpoi

nt Trouble Cause Countermeasure

O

il level

T

oo low

Co

rrect

Contam

inated

Replac

e oil

T

urbocharger oil feed pipe

R

estricted

Repair

or replace

T

urbine housing

Car

bon deposits

Clean

Com

pressor housing

Di

rty

Clean

T

urbine shaft bearings

Wo

rn

Replac

e

OK

OK

OK

OK

OK

NG

NG

NG

NG

NG

NG

Continued f

rom the previous page

00 – 28 SERVICE INF

ORMATION

5) EXCESSIVE ROTATING PART WEAR

Checkpoi

nt Trouble Cause Countermeasure

Engine oil Contam

inated

Change

W

rong grade or type

Change

T

urbocharger oil feed pipe

R

estricted

Clean or

replace

T

urbocharger oil seal

Def

ective

Replac

e

Center

housing oil

drain passage

R

estricted

Clean or

replace

T

urbine shaft

O

il sludge and coking

Replac

e

Engine lubr

ication system

Inadequate oil s

upply

Co

rrect

OK

OK

OK

OK

OK

NG

NG

NG

NG

NG

NG

NG

SERVICE INF

ORMATION 00 – 29

LUBRI

CATION CHART

T

he 4J Series engine lubricating system is a full flow type.

Lubricating oil is pumped from the oil pump to the cylinder body oil gallery through the oil cooler and the oil filter
(replaceable type oil filters have on oil cooler). It is then delivered to the vital parts of the engine from the cylinder
body oil gallery.

4J

B1, 4JB1TC, 4JG2, Oil Filter & Oil Cooler

k

Pa (Kg/cm

2

/ps

i)

!

O

il filter relief valve opening pressure : 559 - 0618 (5.7 - 6.3/81 - 90)

"

O

il cooler safety valve opening pressure : 314 - 373 (3.2 - 3.8/46 - 54)

#

O

il filter safety valve opening pressure : 78 - 118 (0.8 - 1.2/11 - 19)

$

O

il pressure switch opening pressure : 29.4 - 49.0 (0.3 - 0.5/4.3 - 7.1)

Lubu C

hart 5J.tif

00 – 30 SERVICE INF

ORMATION

MA

IN DATA AND SPECIFICATIONS

M

AIN DATA AND SPECIFICATIONS

Item

Engine Model

4J

B1 / 4JB1T / 4JB1TC 4JG2 (G. EXP & EC)

Engine ty

pe Four-cycle, overhead valve, water cooled

Com

bustion chamber type Direct injection In direct injection

Cy

linder liner type Dry type, chrome plated, stainless steel tube

T

iming train system Gear drive Gear and Belt Drive

No. of

cylinders - Bore x stroke mm (in) 4 - 93 x 102

(3.66 x 4.02)

4 - 95.4 x 107

(3.76 x 4.21)

No. of

piston rings Compression rings: 2 / Oil ring: 1

T

otal piston displacement cm

3

(i

n

3

)

2,771 (169.0) 3,059 (186.6)

Com

pression ratio (to 1) 18.2 (4JB1)

18.1 (4JB1T/4JB1TC)

20.1

Com

pression pressure kPa (kg/cm

2

/ps

i) 3,038 (31 / 441) 3,334 (34 / 483.8)

(For EC 2,363 (24.1 / 531))

Engine w

eight (Dry) N (kg/lb) Approximately

2,245 (229 / 505) (4JB1)

2,511 (256 / 564)

(4JB1T/4JB1TC)

Approximately

2,403 (245 / 540)

F

uel injection order 1 - 3 - 4 - 2

F

uel injection timing deg BTDC 14 (4JB1)

BTDC 12 (’91/542A) (4JB1)

BTDC 11 (4JB1T)

BTDC 4 (4JB1TC)

ATDC 1 (Belt ’91/542A)

TDC 0° (Belt ’91/542B)

ATDC 2 (Gear ’91/542A)

Spec

ified fuel type SAE No. 2 diesel fuel

Idling s

peed rpm 750 - 790 700 – 740

Valve c

learances (At cold): Intake mm(in) 0.40 (0.016)

Ex

haust mm(in) 0.40 (0.016)

Valve c

learances (At hot): Intake mm(in) 0.45 (0.018)

Ex

haust mm(in) 0.45 (0.018)

Intak

e valves Open at (BTDC) deg 24.5

Clos

e at (ATDC) deg 55.5

Ex

haust valves Open at (BTDC) deg 54

Clos

e at (ATDC) deg 26

NOT

E: G.EXP : General Export Model

EC : European Countries
Emission Gas Control Standard
’91/542A : Euro 1
’91/542B : Euro 2

SERVICE INF

ORMATION 00 – 31

Item

Engine Model

4J

B1 / 4JB1T / 4JB1TC 4JG2 (G. EXP & EC)

Lubr

icating system

Lubr

ication method Pressurized circulation

Spec

ified engine oil (API grade) CC (4JB1)

CD (4JB1T/4JB1TC)

CC

O

il pump type Gear

O

il filter type Disposable cartridge (Spin-on) Paper element

O

il capacity (Including oil filter)

lit (US/UK gal) 6.6 - 7.1 (1.74 - 1.87/2.62 - 2.82)

(For EC 6.2 - 8.2 (2.17 - 1.64 / 1.36 - 1.80))

O

il cooler type Water cooled

F

uel system

Inj

ection pump type Bosch distributor

G

overnor type Mechanical (Partially variable speed) (For EC Variable speed)

Inj

ection nozzle type Hole Pinttle

Inj

ection nozzle kPa (kg/cm

2

/ps

i)

opening pressure

18,142 (185 / 2,631)

(4JB1/4JB1T)

1st: 19,500 (199 / 2,830)
2nd: 26,500 (270 / 3,840)

(4JB1TC)

14,710 (150/2,133)

Main f

uel filter type Cartridge paper element and water separator

Air

cleaner type Dry paper element

G

enerator capacity V-A (W) 12 - 40 (480) and 12 - 50 (600) 12 - 50 (600)

(For EC 12 - 60 (720))

Star

ter motor output V-kW 12 - 2.0 and 12 - 2.2 12 - 2.2

(For EC 12 - 2.0)

T

urbocharger IHI RHB5 (4JB1T)

IHI RHF4 (4JB1TC)

00 – 32 SERVICE INF

ORMATION

Engi

ne Cooling

Cooling s

ystem
Radiator
Heat radiation capacity kcal/h
Heat radiation area m

2

(f

t

2

)

F

ront area m

2

(f

t

2

)

Dr

y weight N (Kg/lb)
Radiator cap
Valve opening pressure kPa (Kg/cm

2

/ps

i)

Coolant capacity lit (Imp.qt./US qt.)

Coolant forced circulation

(2 tube in row) Tube type Corrugated

71400

11.78 (126.8)

0.216 (2.325)

105 (10.7/23.6)

88.2 - 116.7 (0.899 - 1.199/12.78 - 17.05)

3.1 (2.73/3.28)

(For EC 5.8 (5.1/6.13))

Coolant pum

p
Pulley type
Pulley ratio

Centrifugal impeller type

1.2

T

hermostat type

Valve opening °C (°F)
Valve full open °C (°F)

wax pellet with jiggle valve.

Without jiggle valve (Thailand only)

82 (180)
95 (203)

Coolant total c

apacity Iit (Imp.qt./US qt.) 10 (8.80/10.57) (For EC 7.3 (6.42/7.71))

Starting Sy

stem

Manuf

acturer DENSO

Engine Model

4JB1 / 4JB1T / 4JB1TC 4JG2 (G.EXP & EC)

Rati

ng

Voltage

V 12

O

utput kW 2.0 2.2

Ti

me Sec 30

Num

ber of tooth of pinion 9

Rotating dir

ection (as viewed from pinion) Clockwise

W

eight (approx.) kg 4.6 5.4

No-

load characteristics
Voltage/current V/A
Speed rpm

11.5/100 or less
3700 or more

Load c

haracteristics
Voltage/current V/A
Torque N•m(Kg•m/lb•ft)

7.5/500 or less

13.7 (1.4/10.1)

Speed

rpm 1200 or more 1400 or more

Loc

king characteristics
Voltage/current V/A
Torque N•m(Kg•m/lb•ft)

2.4/800 or less

18 (1.8/13) or more

2.0/850 or less

16 (1.6/12) or more

SERVICE INF

ORMATION 00 – 33

Charging Sy

stem

Manuf

acturer HITACHI LR150-449B DENSO

Rated voltage

V 12 12

Rated output

A 50 40

Rotating dir

ection

(As viewed from pulley)

Clockwise Clockwise

Pulley

effective diameter mm (in) 80 (3.15) 82 (3.23)

W

eight (with pump) kg (lb) 6.0 (13.27)

4JB1TC for G.E

4JB1TC for EC

6.7 (14.77)

4JB1TC for Thailand

00 – 34 SERVICE INF

ORMATION

SERVICE STA

NDARD

Engine M

echanical

mm (

in)

Serv

ice standard Service limit

Parts Items

4JG2

4JB1 / 4JB1T /

4JB1TC

4JG2

4JB1 / 4JB1T /

4JB1TC

Remarks

C

ylinder head deck, and
exhaust manifold mating
surface for flatness

0.05 (0.002) or less 0.2 (0.0079)

C

ylinder head height 92.0 (3.622) 91.55 (3.6043)

C

ylinder

Head

Cylinder Head Lower Face
Warpage.

Manifold Warpage.
Hot plug sinking
Hot plug exert pressure

0.05 (0.002)or less

0.05 (0.002) or less

-

4,500 – 5,500 kg

(9922.5 - 12127.5 lbs)

0.20 (0.008)

0.20 (0.008)

0.02 (0.0008)

-

Cannot be
Reground

Valv

e

Spring

Free height
Squareness
Spring tension N (kg/lb)

48.0 (1.891)

-

296 (30.2/66.4)

47.10 (1.856)

1.7 (0.067)

257.9 (26.3/57.9) At installed
height

38.9 (1.531)

7.946 - 7.961

(0.3128 - 0.3134)

7.921 - 7.936

(0.3118 - 0.3124)

0.039 - 0.069

(0.0015 - 0.0027)

0.064 - 0.096

(0.0025 - 0.0038)

13.0 (0.512)

1.1 (0.0433)

7.880 (0.3102)

7.850 (0.3090)

0.200 (0.0079)

0.250 (0.0098)

-

1.6 (0.0630)

1.41 (0.0556)

1.39 (0.0547)

1.79 (0.0705)

1.83 (0.0720)

1.1 (0.0433)

1.1 (0.0433)

1.5 (0.06)

1.5 (0.06)

Valv

e
and
Valve
Guide

Diameter Valve Stem

IN

EX

Valve and valve guide
clearance IN

EX

Valve guide upper end
height (Measured from the
Cylinder head upper face)

Valve guide margin
Valve thickness IN

EX

Valve seat contact surface
angle

Valve seat contact width

IN

EX

45°

1.7 (0.0669)

2.0 (0.0787)

2.2 (0.0866)

2.5 (0.0984)

SERVICE INF

ORMATION 00 – 35

mm (

in)

Serv

ice standard Service limit

Parts

Items

4JG2

4JB1 / 4JB1T /

4JB1TC

4JG2

4JB1 / 4JB1T /

4JB1TC

Remarks

Push rod

Curvature - 0.4 (0.0157) or less

C

amshaft End play

Cam lobe height
Journal diameter
Runout
Camshaft bearing inside

diameter
Camshaft oil clearance

0.08 (0.0031)

42.02 (1.6543)

49.945 - 49.975(1.9663-1.9675)

0.02 (0.0008) or less

50.000 - 50.030

(1.9685 - 1.9697)

0.025 - 0.085

(0.0098 - 0.00334)

0.2 (0.0079)

41.65 (1.6397)

49.60 (1.9527)

0.10 (0.0039)

50.08(1.9716)

0.12 (0.0047)

Tappet Outside diameter

Oil clearance
(Between tappet and
cylinder body)

12.97 - 12.99 (0.5106 - 0.5114)

0.03 (0.0118)

12.95 (0.5098)

0.10 (0.0039)

R

ocker
arm
Assembly

Rocker shaft outside
diameter

Rocker arm inside
diameter

Oil clearance
(Between rocker arm and
rocker shaft)

Rocker shaft runout

18.98 - 19.00

(0.7472 - 0.7480)

19.036 - 19.060

(0.7494 - 0.7504)

0.06 - 0.08

(0.00235 - 0.00315)

-

18.90 (0.7440)

19.10 (0.7520)

0.10 (0.004)

0.2 (0.0079) or less

O

il clearance

Body and gear

0.14 (0.0055) 0.13 - 0.14
(0.0051-0.0055)

0.20 (0.0079) 0.15 (0.0059)

O

il pump

Body cover and gear 0.06 (0.0024) 0.02 - 0.07

(0.0008-0.0028)

0.15 (0.0059)

C

rankshaft Thrust clearance 0.10 (0.0039) 0.30 (0.018)

Main bearing clearance
(Between main bearing
and Crankshaft)

0.031-0.063

(0.0012-0.0025)

0.035-0.080

(0.0014-0.0032)

0.11

(0.0043)

C

rankshaft runout
Main journal diameter
Crankshaft pin diameter
Crankshaft Journal and

Crank Pin uneven wear
Crank Pin and Bearing

Clearance.

0.05 (0.00197) or less

69.917 - 69.932 (2.7526 - 2.7532)

52.915 - 52.930 (2.0833 - 2.0839)

0.05 (0.002) or less

0.029 - 0.066 (0.0011 - 0.0026)

0.08 (0.0031)

69.91 (2.7524)

52.90 (2.0827)

0.08 (0.003)

0.100 (0.0039)

00 – 36 SERVICE INF

ORMATION

mm (

in)

Serv

ice standard Service limit

Parts

Items

4JG2

4JB1 / 4JB1T /

4JB1TC

4JG2

4JB1 / 4JB1T /

4JB1TC

Remarks

Piston diameter

95.365 - 95.404
(3.7545-3.9039)

92.985 - 93.024

(3.6600-3.6623)

-

Piston,
Pis

ton
pin,
Piston
ring and
Connect­ing rod

Piston Clearance
(Between piston and
Cylinder liner)

Piston ring gap 1st

2nd

Oil

Piston ring clearance 1st

2nd

0.047 - 0.065

(0.0019-0.0026)

0.20 - 0.35

(0.0079 –

0.0138)

0.37 - 0.52

(0.0146 -

0.0205)

0.20 - 0.40

(0.0079 -

0.00157)

0.09 - 0.13

(0.0035 -

0.0051)

0.05 - 0.09

(0.002 -

0.0035)

0.025 - 0.045

(0.0010-0.0018)

0.20 - 0.40

(0.0079 –

0.0157)

0.20 - 0.40

(0.0079 -

0.00157)

0.10 - 0.30

(0.0039 -

0.0118)

0.090 - 0.125

(0.0035 -

0.0049)

0.050 - 0.075

(0.0020 -

0.0030)

-

1.5 (0.0591)

1.5 (0.0591)

1.5 (0.0591)

0.15 (0.0059)

Oil 0.03 - 0.07

(0.0012 - 0.0028)

0.15 (0.0059)

Piston pin diameter

33.995 - 34.000
(1.3384-1.3386)

30.995 - 31.000

(1.2202-1.2204)

33.970

(1.3374)

30.970

(1.2190)

Fitting interference
(Betw

een connecting

rod and piston pin)
Fitting interference

(Between piston and
piston pin)

Connecting rod
alignment Bend

Twist

Piston pin and Connecting
Rod Bushing Clearance

Connecting rod thrust
clearance

0.008 - 0.020

(0.0003 - 0.0008)

0.002 - 0.015

(0.0001 - 0.0006)

0.08 (0.0031) or less

0.05 (0.0020) or less

0.008 - 0.020

(0.0003 - 0.0008)

0.230 (0.0091)

0.05 (0.0020)

0.04 (0.0016)

0.20 (0.0079)

0.15 (0.0059)

0.050 (0.0020)

0.35 (0.0138)

0.029 -0.083

0.029 - 0.066 0.100 (0.0039)

(0.0014 -

(0.0011 -

O

il clearance
(Between crank pin and
Connecting rod) 0.0033) 0.0026)

Per 100

(3.94)

Per 100

(3.94)

SERVICE INF

ORMATION 00 – 37

mm (

in)

Serv

ice standard Service limit

Parts Items

4JG2

4JB1 / 4JB1T /

4JB1TC

4JG2

4JB1 / 4JB1T /

4JB1TC

Remarks

C

ylinder

Block

Warpage
(Upper surface of the
cylinder block)

- 0.20 (0.0079)

Cylinder bore diameter 97.000 - 97.040 95.011 - 95.040

(3.8189 -

(3.7406 -

3.8205)

3.7417)

C

ylinder liner projection 0.0-0.1

(0.00-0.0039)

C

ylinder liner inside 95.420 - 95.460 93.020 - 93.060
diameter

(3.7567 - (3.6622 -

3.7583) 3.6638)

C

ylinder liner outside 97.011-97.050 95.011 - 95.050
diameter (3.8193 - (3.7405 -

3.8209)

3.7421)

00 – 38 SERVICE INF

ORMATION

SERVICING

Ser

vicing refers to general maintenance procedures to be

performed by qualified service personnel.

M

ODEL IDENTIFICATION

Engine Serial Number

T

he engine number is stamped on the front left hand side

of the cylinder body.

AIR CLEANER

Dr

y Type Paper Element

Element cleaning procedures will vary according to the
condition of the element.

Dust fouled Element

Rotate the elem

ent with your hand while applying
compressed air to the inside of the element. This will
blow the dust free.

Compressed air pressure kPa (kg/cm

2

/Ps

i)

392 -

490 (4 - 5/57 - 71)

CA

UTION

Do not ba

ng the element against another object in an

attempt to clean it. Damage to the element will result.

Carbon and Dust Fouled Element

1.

Prepare a cleaning solution of Isuzu Genuine Element
Cleaner (Donaldson D1400) diluted with water.

2. Submerge the element in the solution for twenty

minutes.

0038-

1.tif

0038-2.tif

0038-3.tif

SERVICE INF

ORMATION 00 – 39

3.

Remove the element from the solution and rinse it
well with running water.

Water pressure must not exceed 274 kPa (2.8 kg/cm

2

/40Ps

i)

4.

Dry the element in a well ventilated area.
An electric fan will hasten drying.

NOTE:

Do not use compressed air or an open flame to dry
the element quickly. Damage to the element will
result. It will usually take two or three days for the
element to dry completely. Therefore, it is a good idea
to have a spare on hand to use in the interim.

LUBRI

CATING SYSTEM

Main Oil Filter (Cartridge Type Paper Element)
Replacement Procedure

1.

Loosen the used oil filter by turning it
counterclockwise with the filter wrench.

2.

Clean the oil filter fitting face.
This will allow the new oil filter to seat properly.

3. Apply a light coat of engine oil to the O-ring.

4. Turn in the new oil filter until the filter O-ring is fitted

against the sealing face.

5. Use the filter wrench to turn in the filter an additional 1

and 1/4 turns.
Filter Wrench : 5-8840-0200-0 (89mm/3.5in)

5-8840 0202-0 (106mm/4.2in)
5-8840-2209-0 (100.6mm/4.0in)

6.

Check the engine oil level and replenish to the
specified level if required.

Replenishment Engine Oil lit (Imp qt/US qt)

0.7 (

0.62/0.74)

7.

Start the engine and check for oil leakage from the
main oil filter.

0039-

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0039-2.tif

050LX001.tif

0039-4.tif

00 – 40 SERVICE INF

ORMATION

FUEL SYSTEM

Fuel Filter
Replacement Procedure

1.

Loosen the used fuel filter by turning it
counterclockwise with the filter wrench.

Filter Wrench: 5-8840-0253-0 (J-22700)

2.

Clean the filter cover fitting faces.
This will allow the new fuel filter to seat properly.

3.

Turn in the fuel filter until the sealing face comes in
contact.

4. Turn in the fuel filter an additional 2/3 of a turn with a

filter wrench.
Filter Wrench: 5-8840-0253-0 (J-22700)

5.

Loosen the bleeder plug on the injection pump
overflow valve.

6. Operate the priming pump until fuel begins to flow
from the fuel filter.

7. Retighten the bleeder plug.

8. Operate the priming pump several times and check
for fuel leakage.

NO

TE:

T

he use of an ISUZU genuine fuel filter is strongly

recommended.

Fuel Filter Water Draining Procedure

T

he indicator light will come on when the water level in

the water separator exceeds the specified level.
Drain the water and foreign material from the water

separator with the following procedure.

0040-

1.tif

0040-2.tif

0040-3.tif

0040-4.tif

0041-1.tif

SERVICE INF

ORMATION 00 – 41

1.

Find a safe place to park the vehicle.

2. Open the engine hood and place a container
(Approximately 0.2 liter capacity) at the end of the
vinyl hose beneath the drain plug on the separator.

3. Loosen the drain plug by turning it counterclockwise
(Approximately 5 turns) and operate the priming pump
up and down about 10 times until water is drained
approximately 0.1 liter.

4. After draining, securely tighten the drain plug by
turning it clockwise and operate the priming pump
manually up and down several times.

5. After starting the engine, check to see that there is no
fuel leak from the drain plug. Also check to see that
the fuel filter water indicator light has turned off.

If water separator requires frequent draining, have the
fuel tank drained for removal of water at your Isuzu
Dealer.

Air Bleeding

1.

Loosen the bleeder screw on the injection pump
overflow valve.

2. Operate the priming pump until fuel mixed with foam
flows from the bleeder screw.

3. Tighten the bleeder screw.

4. Operate the priming pump several times and check
for fuel leakage.

COOLING SYSTEM

Coolant Level

Chec

k the coolant level and replenish the radiator reserve

tank as necessary.
If the coolant level falls below the “MIN” line, carefully

check the cooling system for leakage. Then add enough
coolant to bring the level up to the “MAX” line.

Engine coolant change procedure

1.

To change engine coolant, make sure that the engine
is cool.

WARNING:

When t

he coolant is heated to a high
temperature, be sure not to loosen or remove
the radiator cap. Otherwi se you might get
scalded by hot vapor or boiling water. To open
the radiator cap, put a piece of thick clot h on t he
cap and loosen the cap slowly to reduce the
pressure when the coolant has become cooler.

2

Open radiator cap and drain the cooling system by
loosening the drain valve on the radiator and on the
cylinder body.

0041-

2.tif

0041-3.tif

0041-4.tif

0042-1.tif

00 – 42 SERVICE INF

ORMATION

NOTE:

For best

result it is suggested that the engine
cooling system be flushed at least once a year.
it is advisable to flush the interior of the cooling
system including the radiator before using anti­freeze (ethylene-glycol based).

Replace damaged rubber hoses as the engine
anti-freeze coolant is liable t o l eak out even
minor cracks. Isuzu recommends to use lsuzu
genuine anti-freeze (ethylene-glycol based) or
equivalent, for the cooling system and not add
any inhibitors or additives.

CAUTION:
A failure to correctly fill the engine cooling

system in changing or topping up coolant may
sometimes cause the coolant to overflow f r om
the filler neck even before the engine and
radiator are completely full. If the engine runs
under this condition, shortage of coolant may
possibly result in engine overheating. To avoid
such trouble, the following precautions should
be taken in filling the system.

3

To refill engine coolant, pour coolant up to filler neck
using a filling hose which is smaller in outside
diameter of the filler neck.
Othewise air between the filler neck and the filling
hose will block entry, preventing the system from
completely filling up.

4 Keep a filling rate of 9 liter/min. or less. Filling over

this maximum rate may force air inside the engine
and radiator. And also, the coolant overflow will
increase, making it difficult to determine, whether or
not the system is completely full.

5 After filling the system to the full, pull out the filling

hose and check to see if air trapped in the system is
dislodged and the coolant level goes down. Should
the coolant level go down, repeat topping-up until
there is no more drop in the coolant level.

6 After directly filling the radiator, fill the reservoir to the

maximum level.

7 Install and tighten radiator cap and start the engine.

After idling for 2 to 3 minutes, stop the engine and
reopen radiator cap. If the water level is lower,
replenish.

W

ARNING:

When the coolant is heated to a high
temperature, be sure not to loosen or remove
the radiator cap. Otherwi se you might get
scalded by hot vapor or boiling water. To open
the radiator cap, put a piece of thick clot h on t he
cap and loosen the cap slowly to reduce the
pressure when the coolant has become cooler.

8

After tightening radiator cap, warm up the engine at
about 2,000 rpm. Set heater adjustment to the
highest temperature position, and let the coolant
circulate also into heater water system.

9 Check to see the thermostat has opened through the

SERVICE INF

ORMATION 00 – 43

needle pos

ition of water thermomete, conduct a

5 minutes idling again and stop the engine.

10 When the engine has been cooled, check filler neck

for water level and replenish if required. Should
extreme shortage of coolant is found, Check the
coolant system and reservoir tank hose for leakage.

11 Fill the coolant into the reservoir tank up to “MAX”

line.

Cooling System Inspection

Ins

tall a radiator filler cap tester to the radiator. Apply testing

pressure to the cooling system to check for leakage.
T

he testing pressure must not exceed the specified pressure.

T

esting Pressure kPa (Kg/cm

2

/ps

i)

147 (

1.5/21)

Radiator Cap Inspection

T

he radiator filler cap is designed to maintain coolant

pressure in the cooling system at 1.05 kg/cm

2

(

15 psi / 103
kPa). Check the radiator filler cap with a radiator filler cap
tester. The radiator filler cap must be replaced if it fails to
hold the specified pressure during the test procedure.

Radiator Filler Cap Pressure
Pressure Valve kPa (Kg/cm

2

/ps

i)

88 -

118 (0.9 - 1.2/12.8 - 17.1)

Negative Valve (

Reference) kPa (Kg/cm

2

/ps

i)

1.0

- 13.9 (0.01 - 0.04/0.14 - 0.57)

Thermostat Operating Test

1.

Completely submerge the thermostat in water.

2. Heat the water.

Stir the water constantly by suitable wood bar (2) to
avoid direct heat being applied use wood plate (3) to
the thermostat.

3. Check the thermostat initial opening temperature.
Thermostat Initial

Opening Temperature °C (°F)

82 (

180)

4.

Check the thermostat full opening temperature.
Thermostat Full
Opening Temperature °C (°F)

95 (

203)

Valve Lif

t at Fully Open Position mm (in)

10 (

0.39)

0042-

2.tif

0042-3.tif

0042-4.tif

00 – 44 SERVICE INF

ORMATION

Drive Belt Adjustment

Depr

ess the drive belt mid portion with a 98N (10 kg/22

lb) force.
Drive Belt Deflection mm (in)

10 (

0.39)

Chec

k the drive belt for cracking and other damage.

1. Crankshaft damper pulley

2. Generator pulley

3. Cooling fan pulley

4. Oil pump pulley or idler pulley

5. Compressor pulley or idle pulley

Cooling Fan Pulley Drive Belt

F

an belt tension is adjusted by moving the generator.

Depress the drive belt mid portion with a 98N (10 kg/22
lb) force.

1. Crankshaft damper pulley

2. Generator pulley

3. Cooling fan pulley

Compressor Pulley Drive Belt

Move the idler

pulley as required to adjust the compressor

drive belt tension.
If the vehicle is equipped with power steering, move the

oil pump as required.
Depress the drive belt mid portion with a 98N (10 kg/22

lb) force.
Belt Deflection mm (in)

14 -

17 (0.55 - 0.67)

1.

Crankshaft damper pulley

2. Oil pump pulley or idler pulley

Power Steering Oil Pump Pulley Drive Belt

Move the oil pum

p as required to adjust the oil pump drive

belt tension.
On air conditioner equipped models, both drive belts

pulley must always be replaced as a set.
Depress the drive belt mid portion with a 98N (10 kg/22

lb) force.
Belt Deflection mm (in)

14 -

17 (0.55 - 0.67)

1.

Crankshaft damper pulley

2. Oil pump pulley

3. Compressor pulley or idler pulley

0043-

1.tif

0043-2.tif

0043-3.tif

0043-4.tif

SERVICE INF

ORMATION 00 – 45

ENGI

NE CONTROL

Idling Speed Inspection

1.

Set the vehicle parking brake and choke the drive

wheels.

2. Place the transmission in neutral.

3. Start the engine and allow it to warm up.

4. Disconnect the engine control cable from the control

lever.

5. Set a tachometer to the engine.

6. Check the engine idling speed.

If the engine idling speed is outside the specified

range, it must be adjusted.
Engine Idling Speed rpm

4JB1 / 4JB1T / 4JB1TC 750 - 790

4J

G2 700 - 740

Idling Speed Adjustment

1.

Loosen the idling set bolt lock nut on the injection

pump idling set bolt.

2. Adjust the idling speed to the specified range by
turning the idling set bolt.

3. Lock the idling set bolt with the idling set bolt lock nut.

4. Check that the idling control cable is tight (free of
slack).

If required, remove the slack from the cable.

Accelerator Control Cable Adjustment

1.

Loosen the accelerator cable clamp bolt.

2. Check that the idling control knob on the instrument
panel is in the engine idling position.

3. Hold the accelerator lever in the fully closed position
and stretch the control cable in the direction indicated
by the arrow to remove any slack.

Accelerator Pedal Adjustment

1.

Loosen the lock nut.

2. Adjust bolt height from floor.

Adjust Bolt Height A mm (in)

18 -

28 (0.71 - 1.1)

0044-

1.tif

0044-2.tif

00 – 46 SERVICE INF

ORMATION

1.

Hold the accelerator pedal pad securely by hand, and
give it a full stroke.

2. Adjust the stopper bolt so that the clearance between
the pad stopper bolt and the rear side of the pad
becomes the specified length.

mm (in)

0 -

2 (0 - 0.079)

3.

Check to see if the accelerator pedal play is in the
range of 5 to 10mm above the pedal pad.

4. Press down on the accelerator pedal fully and check
to see if the engine rotates at its maximum speed with
each of the linkage in the smooth operation.

5. In the operating range of accelerator pedal and the
injection pump lever returns to their respective original
positions without fail.

VALVE CLEARANCE ADJUSTMENT

1.

Bring the piston in either the No. 1 cylinder or the No.
4 cylinder to TDC on the compression stroke by
turning the crankshaft until the crankshaft damper
pulley TDC line is aligned with the timing pointer.

2.

Check the rocker arm shaft bracket nuts for
looseness.

Tighten any loose rocker arm shaft bracket nuts
before adjusting the valve clearance.

Rocker Arm Shaft
Bracket Nut Torque N∙m (kg∙m/lb∙ft)

54 (

5.5/40)

3.

Check for play in the No. 1 intake and exhaust valve
push rods.

If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.

If the No. 1 cylinder intake and exhaust valve push
rods are depressed, the No. 4 piston is at TDC on the
compression stroke.

0045-1.tif

0045-2.tif

0045-3.tif

0045-4.tif

SERVICE INF

ORMATION 00 – 47

Adj

ust the No. 1 or the No. 4 cylinder valve clearance
while their respective cylinders are at TDC on the
compression stroke.

Valve Clearance (At Cold) mm (in)

0.4 (

0.016)

4.

Loosen each valve clearance adjusting screw as
shown in the illustration.

5. Insert a feeler gauge of the appropriate thickness
between the rocker arm and the valve stem end.

6.

Turn the valve clearance adjusting screw until a slight
drag can be felt on the feeler gauge.

7. Tighten the lock nut securely.

8. Rotate the crankshaft 360°.

9. Realign the crankshaft damper pulley TDC notched
line with the timing pointer.

10. Adjust the clearance for the remaining valves as
shown in the illustration.

INJECTION TIMING ADJUSTMENT

1.

Check that the notched line on the injection pump
flange is aligned with the front plate or the timing gear
case notched line.

2.

Bring the piston in the No.

!

c

ylinder to TDC 1 on the
compression stroke by turning the crankshaft until the
crankshaft pulley TDC line is aligned with the timing
mark

"

.

Not

e:

Ch

eck for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.

3.

Disconnect the injection pipe from the injection pump.

4. Remove one bolt from the distributor head.

5. Insert a screwdriver into a hole in the fast idle lever

and turn the lever to release the W-C.S.D. function. (If
so equipped)

6. Install the static timing gauge

#

.

T

he probe of the gauge should be depressed inward

approximately 2 mm (0.079 in).
Static Timing Gauge : 5-8840-0145-0 (J-28827)

0046-

1.tif

0046-2.tif

0046-3.tif

0046-4.tif

0046-5.tif

00 – 48 SERVICE INF

ORMATION

7.

Rotate the crankshaft to bring the piston in the No. 1
cylinder to a point 30 - 40° BTDC.

8. Set the timing gauge needle to zero.

9. Move the crankshaft pulley slightly in both directions

to check that the gauge indication is stable.

10. Turn the crankshaft clockwise and read the gauge
indication when the crankshaft pulley timing mark is
aligned with the pointer.

mm (in)

4JB1 BTDC 14°

4J

B1T BTDC 11°

4J

B1TC BTDC 4°

4J

G2 ATDC 2°

Standar

d Reading mm (in)

0.5 (

0.02)

If

the injection timing is outside the specified range,

continue with the following steps.

11.

Loosen the injection pump fixing nuts and bracket
bolts.

12. Adjust the injection pump setting angle.
When large than

standard value

When smaller than

standard value

G

ear drive A B

A :

Move the injection pump toward the engine.
B : Move the injection pump away from the engine.
Tighten the pump fixing nut, adjust bolt and pump

distributor head plug to the specified torque.
Pump Fixing Bolt N∙m (kg∙m/lb∙ft)

24 (

2.4/17)

Adj

ust Bolt N∙m (kg∙m/lb∙ft)

19 (

1.9/14)

Inj

ection Pump

Distributor Head Plug N∙m (kg∙m/lb∙ft)

17 (

1.7/12)

CA

UTION

• Whe

n installing the distributor head/plug, be sure

to use new copper washer.

0047-1.tif

0047-2.tif

0047-3.tif

SERVICE INF

ORMATION 00 – 49

COM

PRESSION PRESSURE MEASURE-

MENT

1.

Start the engine and allow it to idle until the coolant

temperature reaches 70 - 80°C (158 - 176°F).

2. Remove the following parts.

* Glow plugs

* Fuel cut solenoid connector

* QOS (Quick-On Start System) fusible link wire at

the connector.

3. Set the adapter and compression gauge to the No. 1

cylinder glow plug hole.

Compression Gauge

(with Adapter): 5-8840-2008-0 (J-29762)

Adapter: 5-8531-7001-0

4. Turn the engine over with the starter motor and take

the compression gauge reading.
Compression Pressure at 200 rpm kPa (Kg/cm

2

/ps

i)

Standard Limit

4J

B1 3,038 (31/441) 2,157 (22/313)

4J

G2 3,334 (34/484) 2,452 (25/356)

5.

Repeat the procedure (Steps 3 and 4) for the

remaining cylinders.

If the measured value is less than the specified limit,

refer to “Troubleshooting” in this Manual.

QUICK-ON STA

RT II SYSTEM

(4JB1 / 4JB1T / 4JB1TC only)

Quick-On Start System Inspection Procedure

1.

Disconnect the thermo-sensor connection on the

thermostat outlet pipe.

2. Turn the starter switch to the “ON” position.

If the Quick-On Start II System is operating properly,

the glow relay will make a clicking sound within 15

seconds after the starter switch is turned on.

3.

Measure the glow plug terminal voltage with a circuit

tester immediately after turning the starter switch to

the “ON” position.
Glow Plug Terminal Voltage V

Appr

ox. 11

0048-

1.tif

0048-2.tif

0048-3.tif

0048-4.tif

00 – 50 SERVICE INF

ORMATION

QU

ICK-ON START III SYSTEM

(4JG2 only)

Quick-On Start System Inspection Procedure

1.

Disconnect the thermo-sensor connection on the

thermostat outlet pipe.

2. Turn the starter switch to the “ON” position.

If the Quick-On Start III System is operating properly,

the glow relay will make a clicking sound within seven

seconds after the starter switch is turned on.

3.

Measure the glow plug terminal voltage with a circuit

tester immediately after turning the starter switch to

the “ON” position.
Glow Plug Terminal Voltage V

8 – 9

NO

TE:

Electrical pow

er to the quick-on start system will be
cut after the starter has remained in the “ON”
position for twenty seconds.

Turn the starter switch to the “OFF” position and
back to the “ON” position.

This will reset the Quick-On Start III System.

0049-

1.tif

0049-2.tif

SERVICE INF

ORMATION 00 – 51

FIXING T

ORQUE

CYLI

NDER HEAD COVER, CYLINDER HEAD ROCKER,

SHAFT BRAKER

N∙m (

kg∙m/lb∙ft)

011LX

002.tif

00 – 52 SERVICE INF

ORMATION

Crankshaft, Bearing Cap, Connecting Rod Bearing Cap, Crankshaft Damper
Pu

lley, Flywheel, Oil Pan

N∙m (

kg∙m/lb∙ft)

0051-

1.tif

SERVICE INF

ORMATION 00 – 53

Ti

ming Pulley Housing, Timing Pulley, Timing Gear,

Camshaft Oil Seal Retainer

N∙m (

kg∙m/lb∙ft)

014LX

001.tif

00 – 54 SERVICE INF

ORMATION

Cool

ing System and Lubrication System

N∙m (

kg∙m/lb∙ft)

SERVICE INF

ORMATION 00 – 55

Intake M

anifold, Exhaust Manifold, Exhaust Pipe

N∙m (

kg∙m/lb∙ft)

150LX

004.tif

00 – 56 SERVICE INF

ORMATION

N∙m (

kg∙m/lb∙ft)

036LX

003.tif

SERVICE INF

ORMATION 00 – 57

Engine Electricals

N∙m (

kg∙m/lb∙ft)

0056-

1.tif

00 – 58 SERVICE INF

ORMATION

Engi

ne Fuel

N∙m (

kg∙m/lb∙ft)

0057-

1.tif

SERVICE INF

ORMATION 00 – 59

Engi

ne Mounting Bracket

N∙m (

kg∙m/lb∙ft)

0058-

1.tif

00 – 60 SERVICE INF

ORMATION

SPECIA

L TOOLS

ILLUSTRATION TOOL NO. TOOL NAME

5-

8840-2035-0 Crank Timing Pulley (4JG2 Belt Drive only)

5-

8840-0200-0 Oil Filter Wrench (89.0 mm/3.5 in)

5-

8840-0202-0 Oil Filter Wrench (106.0 mm/4.2 in)

5-

8840-2209-0 Oil Filter Wrench (100.6 mm/4.0 in)

9-

8523-1423-0 (J-29760) Valve Spring Compressor

5-

8840-2033-0 Oil Seal Installer

5-

8840-9018-0 Piston Ring Compressor

5-

8840-2093-0 Tacho Meter

9-

8523-1212-0 Valve Guide Replacer

5-

8840-0086-0

Camshaft Timing Pulley Remover
(4JG2 Belt Drive only)

5-

8840-0199-0 Rubber Hardness Tester

SERVICE INF

ORMATION 00 – 61

SPECIA

L TOOLS (CONT.1)

ILLUSTRATION TOOL NO. TOOL NAME

5-

8840-2675-0 Compression gauge

5-

8531-7001-0 Gauge Adapter

5-

8531-7002-0 Gauge Adapter

5-

8840-0145-0 Measuring Device

5-

8522-0024-0

Crankshaft Timing Pulley Installer
(4JG2 Belt Drive only)

5-

8840-0266-0 Angle Gauge

5-

8840-9016-0 Injection Nozzle Tester

5-

8840-2034-0 Nozzle Holder Remover (4JB1 only)

5-

8840-2038-0 Camshaft Bearing Replacer

5-

8840-2036-0

Front Oil Seal Installer
(4JB1, 4JG2, Gear Drive only)

00 – 62 SERVICE INF

ORMATION

SPECIA

L TOOLS (CONT.2)

LLUSTRATION TOOL NO. TOOL NAME

5-

8840-0259-0 Nozzle Holder Wrench (4JG2 only)

5-

8840-0253-0 (J-22700) Fuel Filter Wrench

5-

8840-2362-0 Front Oil Seal Remover (4JG2, Belt Drive only)

5-

8840-2361-0 Front Oil Seal Installer (4JG2, Belt Drive only)

5-

8840-2360-0 Rear Oil Seal Remover

5-

8840-2359-0 Rear Oil Seal Installer

5-

8840-2040-0 Cylinder Liner Installer (4JB1 only)

5-

8840-2313-0 Cylinder Liner Installer (4JG2 only)

5-

8840-2039-0 Cylinder Liner Remover (4JB1 only)

5-

8840-2304-0 Cylinder Liner Remover Ankle (4JG2 only)

5-

8840-2000-0 Pilot Bearing Remover

5-

8840-0019-0 Sliding Hammer

5-

8522-0024-0 Pilot Bearing Installer