TROUBLESHOOTING 6 – 1
SECTION 6
TROUBLESHOOTING
TABLE OF CONTENTS
PAGE PAGE
BASIC INSPECTION PROCEDURE ... 6– 2
1. HARD STARTING ........................... 6– 3
1-1.Starter Motor Inoperative ......... 6– 3
1-2. Starter Motor Operates But
Engine Does Not Turn Over .......... 6– 3
1-3. Engine Turns Over But Does
Not Start Engine ............................. 6– 4
2. UNSTABLE IDLING ........................ 6– 5
3. INSUFFICIENT POWER ................. 6– 6
4. EXCESSIVE FUEL
CONSUMPTION ................................. 6– 7
5. EXCESSIVE OIL CONSUMPTION.. 6– 8
6. OVERHEATING............................... 6– 9
7. WHITE EXHAUST SMOKE ............. 6– 9
8. DARK EXHAUST SMOKE .............. 6– 10
9. OIL PRESSURE DOES NOT RISE . 6– 11
10. ABNORMAL ENGINE NOISE ....... 6– 12
10-1. Engine Knocking.................... 6– 12
10-2. Gas Leakage Noise ................ 6– 12
10-3. Continuous Noise .................. 6– 13
10-4. Slapping Noise ....................... 6– 13
10-5. Excessive Turbocharger
Noise ............................................... 6– 14
11. ROTATING PART WEAR OF
TURBOCHARGER ............................. 6– 14
12. OIL LEAKAGE FROM
TURBOCHRGER ............................... 6– 15
13. INSUFFICIENT ACCELERATION
AND/OR LACK OF POWER DUE
TO TURBOCHARGER ....................... 6– 15
14. BATTERY CHARGING AND
NOISE PROBLEM.............................. 6– 16
14-1. Battery No Charging .............. 6– 16
14-2. Battery Overcharging ............ 6– 16
14-3. Battery Under Charging......... 6– 17
14-4. Battery Unstable Charging
Current ............................................ 6– 17
14-5. Charging System Noise ......... 6– 18
15. STARTER MOTOR PROBLEM..... 6– 19
15-1. Starter Motor Pinion Engages
to Ring Gear But Engine Does
Not Turn Over ................................. 6– 19
15-2. Incorrect Pinion And Ring
Gear Engagement .......................... 6– 19
15-3. Starter Motor Continues To
Run After The Starter Switch Is
Turned Off ....................................... 6– 20
15-4. Excessive Commutator
Sparking .......................................... 6– 20
6 – 8 TROUBLESHOOTING
5. Excessive Oil Consumption
Step Action Value(s) Yes No
1 Does the air cleaner element conditon OK? (Clogged
or not) —
Go to Step 2 Clean or
replace the air
cleaner
element
2 Does PCV (Positive Crankcase Ventilation) Valve
has problem? — Repair or
replace the
relation parts. Go to Step 3
3 Was the oil pressure value more than normal value? Less than
588 kPa (6.0
kg/cm
2, 85
psi) Repair or
replace the oil
relief valve Go to Step 4
4 Inspect the front and rear crankshaft oil seal.
Was the oil leakage found? —
Replace the
failure part. Go to Step 5
5 Was the oil leakage found from any gasket? — Replace the
wrong gasket Go to Step 6
6 Inspect the valve stem seal, the valve stem and the
valve guide for worn.
Were any worn found? —
Replace the
worn part. Go to Step 7
7 Was the oil leakage found from the turbocharger oil
seal? — Replace the oil
seal. Go to Step 8
8 Was the oil drain pipe of the turbocharger restricted?— Repair or
replace the oil
drain pipe. Go to Step 9
9 Was the oil drain passage in the turbocharger center
housing restricted? — Clean the
center housing Go to Step 10
10 Does turbine wheel has any impact damage? — Replace the
turbocharger Go to Step 11
11 Are any DTC stored? — Go to indicated
DTC Solved
TROUBLESHOOTING 6 – 9
6. Overheating
Step Action Value(s) Yes No
1 Was the engine coolant level OK? —
Go to Step 2 Replenish the
coolant
2 Was the water leakage or the radiator restriction
found? (Include radiator cap) — Repair or
replace the
leakage part. Go to Step 3
3 Was the fan belt slippage found? — Tension or
replace the fan
belt. Go to Step 4
4 Was the fan clutch working completely? —
Go to Step 5 Replace the
fan clutch
assembly.
5 Was the oil leakage found from fan clutch? — Replace the
fan clutch
assembly Go to Step 6
6 Was the thermostat working normally? —
Go to Step 7 Replace the
thermostat.
7 Was the water pump working OK? —
Go to Step 8 Replace the
water pump
assembly.
8 Was the restriction by the foreign materials in the
cooling system found? For example, clog the water
hose between the cylinder body and radiator etc.. — Clean or
replace the
clog part. Go to Step 9
9 Was the water leakage found from the sealing cap
on the cylinder body? — Replace the
sealing cap or
replace the
cylinder body. Go to Step 10
10 Are any DTC stored? — Go to indicated
DTC. Solved
7. White Exhaust Smoke
Step Action Value(s) Yes No
1 Was the compression pressure OK? 3.0 MPa
(31.0 kg/cm2,
441 psi) at
200 rpm
Go to Step 2 Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and relation
parts.
2 Was the PCV (Positive Crankcase Ventilation) valve
working completely? —
Go to Step 3 Repair or
replace the
PCV valve.
3 Was the turbocharger working completely? —
Go to Step 4 Replace the
turbocharger.
4 Are any DTC stored? — Go to indicated
DTC Solved
6 – 10 TROUBLESHOOTING
8. Dark Exhaust Smoke
Step Action Value(s) Yes No
1 Was the air cleaner element normal condition? —
Go to Step 2 Clean or
replace the air
cleaner
element
2 Was the EGR valve sticking? — Replace the
EGR valve Go to Step 3
3 Was the injection nozzle pressure or the injection
spray pattern OK? —
Go to Step 4 Replace the
injection nozzle
4 Was the oil leakage found from the turbocharger oil
seal? — Replace the oil
seal Go to Step 5
5 Was the oil drain pipe of the turbocharger restricted?— Repair or
replace the oil
drain pipe Go to Step 6
6 Was restricted the oil drain passage in the
turbocharger center housing restricted? — Clean the
center housing Go to Step 7
7 Does turbine wheel has any impact damage? — Replace the
turbocharger Go to Step 8
8 Does PCV (Positive Crankcase Ventilation) Valve
has problem? — Repair or
replace the
relation parts Go to Step 9
9 Are any DTC stored? — Go to indicated
DTC Solved
TROUBLESHOOTING 6 – 11
9. Oil Pressure Does Not Rise
Step Action Value(s) Yes No
1 Was the oil pressure warning lamp working OK? —
Go to Step 2 Replace the oil
pressure
warning lamp
2 Does the oil filter element clog? — Replace the oil
filter element Go to Step 3
3 Does the relief valve open? — Repair or
replace the
relief valve Go to Step 4
4 Does the oil strainer clog? — Clean or
replace the oil
strainer Go to Step 5
5 Was the oil pump working OK? (The pump related
parts worn etc.) —
Go to Step 6 Repair or
replace the oil
pump.
6 Was the rocker arm and/or relation parts worn? — Replace the
rocker arm
and/or relation
parts Go to Step 7
7 Was the camshaft and/or relation parts worn? — Replace the
camshaft
and/or relation
parts Go to Step 8
8 Was the crankshaft and/or relation parts worn? — Replace the
crankshaft
and/or relation
parts Go to Step 9
9 Are any DTC stored? — Go to indicated
DTC Solved
Table of pressure unit
Pressure kPa (kg/cm
2) 100
(1.0) 980
(10.0)
Resistance ohm 81 30
Electric current A 63.5 106.7
6A – 4 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JA1T (L) 4JA1TC
Engine type
Combustion chamber type
Cylinder liner type
Timing gear train system Four-cycle, overhead valve, water cooled
Direct injection
Dry type, chrome plated
Gear drive
No. of cylinders-bore stroke mm (in) 4 – 93 92 (3.66 3.62)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement cm3 (in3)
Compression ratio (to 1) 2,499(152.4)
18.5
Compression pressure Mpa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) Approximately 239 (527)
Fuel injection order 1 – 3 – 4 - 2
Fuel injection timing BTDC deg 8 -
Specified fuel type
Idling speed rpm
Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system JIS No. 2, DIN/EN590, GB252-1944 Diesel fuel
730 25 (A/C Off)
850 25 (A/C ON)
0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0
Injection pump type BOSCH distributor VE type BOSCH distributor VP44 type
Governor type Mechanical (Half all speed
type) Electronically controled
Injection nozzle type
Injection nozzle opening pressure Hole with 5 orifices
Mpa(kg/cm2/psi) 1st 19.1 (195 / 2,773) 1st 19.0 (194 / 2,755)
2nd (Reference)
25.527.0
(260275 / 3,7023,920) 2nd (Reference)
34.035.5
(347362 / 4,9365,154)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator
Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)
6A – 6 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JH1TC
Engine type Four-cycle, overhead valve, water cooled
Combustion chamber type Direct injection
Cylinder liner type
Timing gear train system Dry type, chrome plated
Gear drive
No. of cylinders-bore stroke mm (in) 4 – 95.4 104.9 (3.76 4.13)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement liter
Compression ratio (to 1) 2,999
18.3
Compression pressure MPa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) MT : Approximately 249 (549)
AT : Approximately 236 (520)
Fuel injection order 1 – 3 – 4 - 2
Specified fuel type JIS No.2, DIN/EN590, GB252-1944 Diesel fuel
Idling speed rpm
700 25 (A/C OFF)
800 25 (A/C ON)
Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system
Injection pump type 0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0
BOSCH distributor VP44 type
Injection nozzle type
Injection nozzle opening pressure
MPa(kg/cm
2/psi)Hole with 5 orifices
1st 19.5 (199/2,828)
2nd (Reference) 34.335.8 (350365/4,9805,197)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator
Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)
Oil pump type
Oil filter type Gear
Cartridge paper element
Oil capacity lit (US/UK gal)
6.2 (1.64/1.36) (For 4 2)
7.0 (1.85/1.54) (For 4 4)
Oil cooler type Water cooled
6A – 24 ENGINE MECHANICAL
SERVICING
Servicing refers to general maintenance procedures to be performed by qualified service personnel.
RTW36ASH000401
MODEL IDENTIFICATION
Engine Serial Number
The engine number is stamped on the rear left hand side
of the cylinder body.
The engine number is stamped in the plate in front of the
engine room as well.
AIR CLEANER
Element cleaning procedures will vary according to the
condition of the element.
Dust Fouled Element
Rotate the element 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 /psi)
392 – 490 (4 – 5/57 – 71)
LUBRICATING SYSTEM
Main Oil Filter (Cartridge Type Paper Element)
Replacement Procedure
1. Drain the engine oil.
2. Retighten the drain plug.
3. Loosen the used oil filter by turning it counterclockwise
with a filter wrench.
Filter Wrench: 5-8840-0200-0
RTW36ASH000101
4. Clean the oil cooler fitting face. This will allow the new
oil filter to seat properly.
5. Apply a light coat of engine oil to the filter O-ring.
6. Turn in the new oil filter until the filter O-ring is fitted
against the sealing face.
7. Use the filter wrench to turn in the filter an additional
2/3 turns.
8. Check the engine oil level and replenish to the
specified level if required.
130RY00003
6A-6