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 – 2 TROUBLESHOOTING
Basic Inspection Procedure
Follow the under inspection procedure, when the problem vehicle comes workshop.
Step Inspection point Inspection result YES NO
1 Check the check engine lamp Is the check engine lamp turn
ON ? Go to section
6E “On Board
Diagnostic
(OBD) System
Check" Go to Step 2
2 The battery fluid level and the
gravity Was the problem found? Re-charge the
battery or
replace the
battery Go to Step 3
3 The engine coolant capacity Was the problem found? Replenish the
engine coolant Go to Step 4
4 The engine oil level Was the problem found? Replenish the
engine oil Go to Step 5
5 The air cleaner element Was the problem found? Clean or
replace Go to Step 6
6 The piping fixing condition (oil,
vacuum and fuel piping) Was the problem found? Return normal
condition Go to Step 7
7 The drive belt tension and break Was the problem found? Re-adjust the
tension or
replace Go to Step 8
8 Go to section 6E “On Board
Diagnostic (OBD) System
Check” Was the problem found?
Verify repair Go to Step 9
9 Go to mechanical
troubleshooting chart Was the problem found?
Verify repair —
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 – 14 TROUBLESHOOTING
10-5 Excessive turbocharger noise
The vibration noise (the air aspiration noise) occurred when turbocharger rotates, it is normal condition of the
turbocharger, no necessary any actions.
Step Action Value(s) Yes No
1 Was the excessive noise coming from the
turbocharger? —
Go to Step 2 Go to Step 10
2 Inspect the fixing bolts and bands.
Was any problem found? — Tighten the
loose parts Go to Step 3
3 Was the intake or exhaust system gasket damaged?— Replace the
damaged
gasket. Go to Step 4
4 Inspect rotation parts condition.
Was the turbine wheel rotation rough? — Replace the
turbocharger. Go to Step 5
5 Inspect the turbine wheel.
Was the turbine wheel rubbing against housing? — Replace the
turbocharger. Go to Step 6
6 Was the turbine wheel damaged? — Replace the
turbocharger. Go to Step 7
7 Were there carbon deposits in the turbine or
compressor housing? — Clean or
replace the
turbocharger. Go to Step 8
8 Inspect the oil supply condition.
Was the oil feed pipe clogged? — Repair or
replace the oil
feed pipe. Go to Step 9
9 Was the turbine shaft bearing worn? — Replace the
turbocharger. Go to Step 10
10 Are any DTC stored? — Go to indicated
DTC Solved
11. Rotating Part Wear of Turbocharger
Step Action Value(s) Yes No
1 Inspect engine oil.
Was it contaminated with foreign materials? — Replace the
engine oil Go to Step 2
2 Was the recommended engine oil grade/viscosity
being used? API CD or
ISUZU
genuine/
10W–30
Go to Step 3 Replace the
engine oil
3 Was the oil feed pipe restricted? — Clean or
replace the oil
feed pipe Go to Step 4
4 Was the oil seal of turbocharger defective? — Replace the oil
seal Go to Step 5
5 Was the center housing oil drain passage clogged? — Clean center
housing or
replace the
turbocharger Go to Step 6
6 Was there oil sludge and/or coking on the turbine
shaft? — Replace the
turbocharger Go to Step 7
7 Are any DTC stored? — Go to indicated
DTC Solved
6 – 18 TROUBLESHOOTING
14-5 Charging System Noise
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Was there intermittent noise or continuous noise and
that could be identified clearly by increasing and
decreasing engine speed? —
Replace the
bearing. Go to Step 3
3 Was there a growling sound and does this sound
stop when the connector was disconnected? — Replace the
stator coil. Go to Step 4
4 Was intermittent sound heard when the generator
was running? — Replace the
brush and/or
slip ring. Go to Step 5
5 Was frictional sound heard when generator was
running? — Clean the slip
ring or replace
the brush. Go to Step 6
6 Are any DTC stored? — Go to indicated
DTC. Solved
TROUBLESHOOTING 6 – 19
15. Starter Motor Problem
Visual/physical check the following items before diagnosis.
The battery terminals connection condition.
The ground connection condition.
The starter motor or the battery fastener condition.
The battery fluid level and specific gravity.
15-1 Starter motor pinion engages to ring gear but engine does not turn over
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Check the contact condition between the brush and
the commutator.
Was the brush and the commutator contact
intermittent? — Replace the
brush or repair
the
commutator. Go to Step 3
3 Were the brush and the commutator contact faces
dirty?
—
Clean contact
face Go to Step 4
4 Was the pinion clutch slipped? — Replace the
pinion clutch Go to Step 5
5 Inspect the armature field coil.
Was there an open circuit or a short circuit in the
armature field coil? — Repair or
replace the
armature field
coil. Go to Step 6
6 Are any DTC stored? — Go to indicated
DTC. Solved
15-2 Incorrect pinion and ring gear engagement
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Inspect the pinion and the ring gear teeth.
Were the pinion and/or the ring gear teeth worn or
broken? —
Replace the
wron parts. Go to Step 3
3 Inspect the pinion gear return movement.
Was the pinion gear return movement incorrect? — Adjust or
replace the
movement
parts. Go to Step 4
4 Are any DTC stored? — Go to indicated
DTC. Solved
ENGINE MECHANICAL 6A – 3
Lubricating Flow ........................................................................................................ 6A- 126
Oil Pump and Oil Filter .............................................................................................. 6A- 127
Oil Pump ..................................................................................................................... 6A- 128
Disassembly............................................................................................................ 6A- 128
Inspection and Repair ............................................................................................ 6A- 129
Reassembly............................................................................................................. 6A- 130
Oil Filter and Oil Cooler ............................................................................................. 6A- 131
Disassembly............................................................................................................ 6A- 131
Inspection and Repair ............................................................................................ 6A- 132
Reassembly............................................................................................................. 6A- 133
Inter Cooler .................................................................................................................... 6A- 135
Removal .................................................................................................................. 6A- 136
Installation .............................................................................................................. 6A- 136
Special Tools.................................................................................................................. 6A- 137
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)