Page 791 of 6020

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
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ISUZU KB P190 2007
Page 792 of 6020
TROUBLESHOOTING 6 – 7
4. Excessive Fuel Consumption
Step Action Value(s) Yes No
1 Was the air cleaner element clogged? — Clean or
replace the air cleaner
element. Go to Step 2
2 Was the air leakage found from the air intake side of
the turbocharger? —
Repair or
replace the air intake side of the
turbocharger. Go to Step 3
3 Was the turbocharger working completely? —
Go to Step 4 Replace the
turbocharger
4 Was there the fuel leakage? — Repair or
replace the fuel leakage part. Go to Step 5
5 Was the compression pressure OK? 3.0 MPa
(31.0 kg/cm2,
441 psi) at 200 rpm
Go to Step 6 Readjust the
valve clearance or replace the cylinder head gasket or
cylinder liner or
piston or piston ring or valve
and valve seat
6 Was the injection nozzle pressure or spray pattern normal? —
Go to Step 7 Replace the
injection nozzle
7 Are any DTC stored? — Go to indicated
DTC Solved
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ISUZU KB P190 2007
Page 793 of 6020

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
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ISUZU KB P190 2007
Page 794 of 6020

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
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ISUZU KB P190 2007
Page 795 of 6020

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
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ISUZU KB P190 2007
Page 799 of 6020

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
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ISUZU KB P190 2007
Page 810 of 6020
ENGINE MECHANICAL 6A – 5
Engine model
Item 4JA1T (L)
4JA1TC
Cooling system
W ater pump type Centrifugal
Thermostat type W ax 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-A12 – 60
12 – 80
Starter motor output V-kW12 – 2.3
Turbocharger model
Turbine type
Compressor type *IHI RHF 4H
Mixed flow type
Backward & rake
*IHI: Ishikawajima-Harima Heavy Industries., Ltd.
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ISUZU KB P190 2007
Page 812 of 6020
ENGINE MECHANICAL 6A – 7
Engine model
Item 4JH1TC
Cooling system
W ater pump type
Thermostat type
Air cleaner type
Battery type/voltage × No. of units
Generator capacity V-A
Starter motor output V-kW
Turbocharger model Turbine type
Compressor type
Centrifugal
W ax pellet with jiggle valve
Dry paper element (except for Euro3 spec) Viscous paper element (for Euro3 spec)
80D26L × 1
95D31L × 1 (OPT)
75D26R × 2 (OPT for EC, MT)
80D26R × 2 (OPT for EC, AT)
12 – 60/12 – 80 12 – 2.3
*IHI RHF5
Mixed flow type Radial-inflow
Backward & rake type Radial-outflow
*IHI: Ishikawajima-Harima Heavy Industries., Ltd.
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ISUZU KB P190 2007