Page 1124 of 4264

6 – 4 TROUBLESHOOTING
1-3 Engine turn over but does not start engine
Incase of the fuel not being delivered to the injection pump
Step Action Value(s) Yes No
1 Check clogged, damaged the fuel piping or the
connector loosen.
Was any problem found? —
Repair replace
problem parts. Go to Step 2
2 Was the over flow valve on the fuel filter closed? — Repair replace
the over flow
valve Go to Step 3
3 Was the fuel filter element clogged? — Replace the
fuel filter
element Go to Step 4
4 Was the fuel line air bled? — Go to Step 5 Bleed the air
5 Are any DTC stored? — Go to indicated
DTC Solved
Incase of the fuel is being delivered to the injection pump
Step Action Value(s) Yes No
1 Was the water contain in the fuel? — Replace the
fuel Go to Step 2
2 Was the fuel line air bled? — Go to Step 5 Bleed the air
3 Was the injection spray condition complete? —
Go to Step 4 Replace the
injection nozzle
4 Was the injection nozzle injection starting pressure
OK? (See below)
Go to Step 5 Replace the
injection nozzle
5 Was the injection nozzle sticking? — Replace the
injection nozzle Go to Step 6
6 Are any DTC stored? — Go to indicated
DTC Solved
Injection nozzle opening pressure
1st = 19.5 MPa (199 kg/cm2, 2828 psi)
Page 1125 of 4264

TROUBLESHOOTING 6 – 5
2. Unstable Idling
Step Action Value(s) Yes No
1 Was the fuel line air bled completely? — Go to Step 3 Bleed the air
2 Was the fuel line leakage or blockage found? — Repair or
replace relation
parts. Go to Step 4
3 Was the water contained in the fuel? — Replace the
fuel Go to Step 5
4 Was the fuel filter element clogged? — Replace the
fuel filter
element Go to Step 6
5 Was the injection starting pressure or the injection
spray condition OK? (See below)
Go to Step 7 Replace the
injection nozzle
6 Was the injection nozzle sticking? See Step 6 Replace the
injection nozzle Go to Step 8
7 Check the throttle valve condition.
Was the idling port clogged in the throttle valve? — Repair or
replace the
throttle valve Go to Step 9
8 Was the valve clearance improper adjusted? 0.4 mm
(0.016 in)
both intake
and exhaust
valves Adjust the
valve clearance Go to Step 10
9 Was the compression pressure OK? 3,040 kPa
(31 kg/cm2,
441 psi) at
200rpm
Go to Step 11 Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and valve seat
10 Are any DTC stored? — Go to indicated
DTC Solved
Injection nozzle opening pressure
1st = 19.5 MPa (199 kg/cm2, 2828 psi)
Page 1126 of 4264

6 – 6 TROUBLESHOOTING
3. Insufficient Power
Step Action Value(s) Yes No
1 Was the air cleaner element condition OK? (Clogged
or not) —
Go to Step 2 Clean or
replace the air
cleaner
element.
2 Was the intake air leakage found from intake
system? — Repair or
replace the
intake air
system. Go to Step 3
3 Was the fuel filter element condition OK? (Clogged
or not) —
Go to Step 4 Clean or
replace the fuel
filter element.
4 Check the fuel injection pipes.
Does the injection pipes have obstruction or any
damage? — Repair or
replace the fuel
injection pipes. Go to Step 5
5 Was the water contained in the fuel? — Replace the
fuel Go to Step 6
6 Was the injection nozzle pressure or spray pattern
normal? —
Go to Step 7 Readjust the
injection nozzle
pressure or
replace the
nozzle.
7 Was the compression pressure OK? 3.0 MPa
(31.0 kg/cm2,
441 psi) at
200 rpm
Go to Step 8 Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and valve seat
8 Was the exhaust pipe clogged? — Repair or
replace the
exhaust pipe. Go to Step 9
9 Was the exhaust gas leakage found from exhaust
system? — Repair or
replace the
exhaust
system. Go to Step 10
10 Was the waste gate control actuator hose broken or
cracked? — Replace the
hose. Go to Step 11
11 Was the waste gate working completely? —
Go to Step 12 Replace the
turbocharger
assembly.
12 Was turbocharger working completely? —
Go to Step 13 Replace the
turbocharger
assembly.
13 Are any DTC stored? — Go to indicated
DTC Solved
Page 1131 of 4264

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
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 1145 of 4264
ENGINE MECHANICAL 6A – 5
Engine model
Item 4JA1T (L) 4JA1TC
Oil pump type
Oil filter type
Oil capacity lit (US/UK gal)
Oil cooler type Gear
Cartridge paper element
6.2 (1.64/1.36)
Water cooled
Cooling system
Water pump type Centrifugal
Thermostat type Wax pellet with jiggle valve
Air cleaner type Dry paper element Viscous paper element
Battery type/voltage No. of units 80D26L 1
95D31L 1 (OPT)
Generator capacity V-A 12 – 60
12 – 80
Starter motor output V-Kw 12 – 2.3
Turbocharger model
Turbine type
Compressor type *IHI RHF 4H
Mixed flow type
Backward & rake
*IHI : Ishikawajima-Harima Heavy Industries., Ltd.
Page 1164 of 4264

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
Page 1165 of 4264

ENGINE MECHANICAL 6A – 25
Replenished Engine Oil MAX lit (US/UK gal)
Condition
Model Engine Dry
With oil filter
replacement Without oil
filter
replacement
4 2
4 4
(4JA1L/TC)6.2 (1.64/1.36) 5.2 4.2
(1.37 1.11
/ 1.14 0.92) 4.5 3.5
(1.19 0.93
/ 0.99 0.77)
4 2
(4JH1TC)
6.2 (1.64/1.36) 5.2 4.2
(1.37 1.11
/ 1.14 0.92) 4.5 3.5
(1.19 0.93
/ 0.99 0.77)
4 4
(4JH1TC) 7.0 (1.85/1.54) 6.2 5.2
(1.64 1.37
/ 1.36 1.14) 5.3 4.3
(1.72 1.14
/ 1.17 0.95)
9. Start the engine and check for oil leakage from the
main oil filter.
6A-7
FUEL SYSTEM
Fuel Filter Replacement Procedure
1. Remove the fuel filter by turning it counterclockwise
with a filter wrench.
Filter Wrench: 5-8840-0253-0 (J-22700)
Note:
Be careful not to spill the fuel in the filter cartridge.
RTW46ASH000501
2. Clean the fuel filter cartridge fitting faces.
This will allow the new fuel filter to seat properly
3. Apply a light coat of engine oil to the O-ring.
4. Turn in the fuel filter until the sealing face comes in
contact with the O-ring.
5. Turn in the fuel filter an additional 2/3 of a turn with a
filter wrench.
Filter Wrench : 5-8840-0253-0 (J-22700)
6. Operate the priming pump until the air discharged
completely from fuel system.
7. Start the engine and check for fuel leakage.
Note:
The use of an ISUZU genuine fuel filter is strongly
recommended.
041RY00009