Isuzu engine 4j series. Manual - part 2

SERVICE INFORMATION  00 – 7

Checkpoint

Possible cause

Correction

Injection timing improperly adjusted

Adjust the injection timing

Insufficient injection volume

Adjust the injection volume

Defective idle spring

Replace the idle spring

Defective governor lever operation

Repair or replace the governor lever

Regulator valve improperly adjustment

Adjust or replace the regulator valve

Broken plunger spring

Replace the plunger spring

Worn plunger

Replace the plunger assembly

Injection pump
(Cont’d)

Worn cam disc

Replace the cam disc

Valve clearance

Valve clearance improperly adjusted

Adjust the valve clearance

Compression pressure

Blown out cylinder head gasket.  Worn
cylinder liner.
Piston ring sticking

Replace the related parts

3. INSUFFICIENT POWER

Checkpoint

Possible cause

Correction

Air cleaner

Clogged air cleaner element

Clean or replace the air cleaner
element

Fuel

Water particle in the fuel

Replace fuel

Fuel filter

Clogged fuel filter element

Replace the fuel filter element or the
fuel filter cartridge

Fuel feed pump

Defective fuel feed pump

Repair or replace the fuel feed pump

Injection nozzle sticking

Replace the injection nozzle

Injection nozzle

Injection nozzle injection starting pressure
too low
Improper spray condition

Adjust or replace the injection nozzle

Fuel injection pipes

Fuel injection pipes damaged or obstructed

Replace the fuel injection pipes

00 – 8

  SERVICE INFORMATION

Checkpoint

Possible cause

Correction

Defective regulating valve

Repair or replace the regulating valve

Defective delivery valve

Replace the delivery valve

Defective timer

Repair or replace the timer

Worn cam disc

Replace the cam disc

Improper control lever operation

Adjust or replace the control lever

Defective injection timing

Adjust the injection timing
Repair or replace the injection pump
timer

Weak governor spring

Replace the governor spring

Injection pump

Worn plunger

Replace the plunger assembly

Compression pressure

Blown out cylinder head gasket.  Worn
cylinder liner.
Piston ring sticking

Replace the related parts

Valve clearance

Valve clearance improperly adjusted

Adjust the valve clearance

Valve spring

Valve spring weak or broken

Replace the valve spring

Exhaust system

Exhaust pipe clogged

Clean the exhaust pipe

Full load adjusting
screw seal

Open and improperly set adjusting screw
seal

Adjust and reseal the adjusting screw

SERVICE INFORMATION  00 – 9

4. EXCESSIVE FUEL CONSUMPTION

Checkpoint

Possible cause

Correction

Fuel system

Fuel leakage

Repair or replace the fuel system
related parts

Air cleaner

Clogged air cleaner element

Clean or replace the air cleaner
element

Idling speed

Poorly adjusted idling speed

Adjust the idling speed

Injection nozzle

Injection nozzle injection starting pressure
too low
Improper spray condition

Adjust or replace the injection nozzle

Fuel injection timing

Fuel injection timing improperly

Adjust the fuel injection timing

Injection pump

Defective Delivery valve resulting is fuel
drippage after fuel injection

Replace the delivery valve

Valve clearance

Valve clearance improperly adjusted

Adjust the valve clearance

Compression pressure

Blown out cylinder head gasket.  Worn
cylinder liner.
Piston ring sticking

Replace the related parts

Valve spring

Valve spring weak or broken

Replace the valve spring

5. EXCESSIVE OIL CONSUMPTION

Checkpoint

Possible cause

Correction

Engine oil

Engine oil unsuitable
Too much engine oil

Replace the engine oil
Correct the engine oil level

Oil seal and gasket

Oil leakage from the oil seal and/or the
gasket

Replace the oil seal and/or the gasket

Air breather

Clogged air breather

Clean the air breather

Intake and exhaust
valve

Worn valve stems and valve guides

Replace the intake and exhaust
valves and the valve guides

00 – 10

  SERVICE INFORMATION

6. OVERHEATING

Checkpoint

Possible cause

Correction

Cooling water

Insufficient cooling water

Replenish the cooling water

Fan clutch

Oil leakage from the fan clutch

Replace the fan clutch

Fan belt

Fan belt loose or cracked causing slippage

Replace the fan belt

Radiator

Defective radiator cap or clogged radiator
core

Replace the radiator cap or clean the
radiator core

Water pump

Defective water pump

Repair or replace the water pump

Cylinder head and
cylinder body sealing
cap

Defective sealing cap resulting in water
leakage

Replace the sealing cap

Thermostat

Defective thermostat

Replace the thermostat

Cooling system

Cooling system clogged by foreign material

Clean the foreign material from the
cooling system

Fuel injection timing

Fuel injection timing improperly adjusted

Adjust the fuel injection timing

7. WHITE EXHAUST SMOKE

Checkpoint

Possible cause

Correction

Cooling water

Insufficient cooling water

Replace the cooling water

Fuel

Water particles in the fuel

Replace the fuel

Fuel injection timing

Delayed fuel injection timing

Adjust the fuel injection timing

Compression pressure

Blown out cylinder head gasket.  Worn
cylinder liner.
Piston ring sticking

Replace the related parts

Inlet and exhaust valve
Valves seals

Defective valve seals.
Worn valves stems and valve guides

Replace the valve seals, the valves,
and the valve guides