Page 1137 of 4264

TROUBLESHOOTING 6 – 17
14-3 Battery Under Charging
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Inspect the brush contact condition on the generator.
Was there intermittent contact between the brush
and the slip ring? — Repair or
replace the
brush holder
assembly. Go to Step 3
3 Inspect the rotor coil on the generator.
Was there a short circuit in the rotor coil? — Repair or
replace the
rotor coil. Go to Step 4
4 Inspect the stator coil on the generator.
Was there an open circuit or the short circuit on the
stator coil? — Repair or
replace the
stator coil. Go to Step 5
5 Inspect the rectifier on the generator.
Was the rectifier defective? — Replace the
rectifier Go to Step 6
6 Inspect the IC regulator on the generator.
Was the IC regulator defective? — Replace the IC
regulator. Go to Step 7
7 Was the electrical load excessive? — Replace more
higher capacity
generator. Go to Step 8
8 Are any DTC stored? — Go to indicated
DTC. Solved
14-4 Battery Unstable Charging Current
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Inspect the brush contact condition on the generator.
Was there poor contact between the brush and the
slip ring? — Repair or
replace the
brush and/or
the slip ring. Go to Step 3
3 Inspect the rotor coil on the generator.
Was there the short circuit or an open circuit in the
rotor coil? — Repair or
replace the
rotor coil. Go to Step 4
4 Inspect the stator coil on the generator.
Was there an open circuit or the short circuit in the
stator coil? — Repair or
replace the
stator coil. Go to Step 5
5 Inspect the connection between the rectifier and
stator coil on the generator.
Was there a loose connection between the rectifier
and stator coil ? —
Repair the
loose
connection. Go to Step 6
6 Inspect the IC regulator on the generator.
Was the IC regulator defective? — Replace the IC
regulator. Go to Step 7
7 Are any DTC stored? — Go to indicated
DTC. Solved
Page 1138 of 4264
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
Page 1139 of 4264

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
Page 1140 of 4264

6 – 20 TROUBLESHOOTING
15-3 Starter motor continues to run after the starter switch is turned off
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Inspect the magnetic switch contact point.
Was the contact point seized? — Repair or
replace the
magnetic
switch. Go to Step 3
3 Inspect the starter switch.
Was the starter switch defective? — Replace the
starter switch. Go to Step 4
4 Are any DTC stored? — Go to indicated
DTC. Solved
15-4 Excessive commutator sparking
Step Action Value(s) Yes No
1 Was “Visual/Physical Check" performed.
—
Go to Step 2 Go to
visual/physical
check
2 Inspect 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 Was there the slag accumulation on the contact
face? — Clean the
contact face or
replace the
brush. Go to Step 4
4 Was the brush holder loose? — Repair the
brush holder Go to Step 5
5 Inspect the commutator.
Was there excessive wear or pitting? — Repair or
replace the
commutator. Go to Step 6
6 Was there loose the solder on the commutator? — Clean and
repair Go to Step 7
7 Inspect the armature shaft.
Was the run-out of armature shaft outside the
standard value due to worn bearing ? —
Replace the
bearing Go to Step 8
8 Are any DTC stored? — Go to indicated
DTC. Solved
Page 1141 of 4264

ENGINE MECHANICAL 6A – 1
SECTION 6A
ENGINE MECHANICAL
TABLE OF CONTENTS
PAGE
Main Data and Specifications ....................................................................................... 6A - 4
Torque Specifications ................................................................................................... 6A - 8
Standard Bolts ........................................................................................................... 6A - 8
Special Parts Fixing Nuts and Bolts ........................................................................ 6A - 9
Recommended Liquid Gasket ...................................................................................... 6A - 22
LOCTITE Application Procedure .................................................................................. 6A - 23
Servicing......................................................................................................................... 6A - 24
Model Identification ................................................................................................... 6A - 24
Air Cleaner .................................................................................................................. 6A - 24
Lubricating System .................................................................................................... 6A - 24
Fuel System ................................................................................................................ 6A - 25
Cooling System .......................................................................................................... 6A - 27
Valve Clearance Adjustment ..................................................................................... 6A - 31
Compression Pressure Measurement ...................................................................... 6A - 32
General Description....................................................................................................... 6A- 36
Removal and Installation............................................................................................... 6A- 37
Removal ...................................................................................................................... 6A- 37
Installation .................................................................................................................. 6A- 40
Coolant Replenishment.......................................................................................... 6A- 41
Engine Warm-Up..................................................................................................... 6A- 41
Engine Repair Kit ........................................................................................................... 6A- 42
Engine Overhaul ............................................................................................................ 6A- 43
Removal ...................................................................................................................... 6A- 43
External Parts ......................................................................................................... 6A- 43
Page 1142 of 4264

6A – 2 ENGINE MECHANICAL
Disassembly ............................................................................................................... 6A- 47
Internal Parts........................................................................................................... 6A- 47
Major Components.............................................................................................. 6A- 47
Minor Components ............................................................................................. 6A- 56
Rocker Arm Shaft and Rocker Arm................................................................ 6A- 56
Cylinder Head .................................................................................................. 6A- 57
Piston and Connecting Rod ........................................................................... 6A- 59
Inspection and Repair................................................................................................ 6A- 61
Cylinder Head ......................................................................................................... 6A- 61
Rocker Arm Shaft and Rocker Arm ....................................................................... 6A- 68
Cylinder Body ......................................................................................................... 6A- 69
Camshaft ................................................................................................................. 6A- 77
Crankshaft and Bearing ......................................................................................... 6A- 79
Crankshaft Bearing Selection................................................................................ 6A- 83
Crankshaft Pilot Bearing........................................................................................ 6A- 85
Flywheel and Ring Gear ......................................................................................... 6A- 85
Piston....................................................................................................................... 6A- 86
Cylinder Head Gasket Selection............................................................................ 6A- 88
Connecting Rod ...................................................................................................... 6A- 90
Idler Gear Shaft and Idler Gear.............................................................................. 6A- 91
Timing Gear Case Cover ........................................................................................ 6A- 91
Reassembly ................................................................................................................ 6A- 93
Internal Parts........................................................................................................... 6A- 93
Minor Component ............................................................................................... 6A- 93
Rocker Arm Shaft and Rocker Arm................................................................ 6A- 93
Cylinder Head .................................................................................................. 6A- 94
Piston and Connecting Rod ........................................................................... 6A- 96
Positive Crankcase Ventilation (PCV) Valve ................................................. 6A- 99
Major Component................................................................................................ 6A- 101
Installation .................................................................................................................. 6A- 118
External Parts ......................................................................................................... 6A- 118
Lubrication System........................................................................................................ 6A- 126
Page 1143 of 4264

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
Page 1144 of 4264

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)