Doosan D439E - Page 149

D439E Service Manual 4. Fuel system
147
Troubles Possible causes Corrective actions
Loose fuel hose connection between
filter and supply pump
Tighten or repair.
Air in the fuel system Air bleeding of fuel system
Fuel filter is clogged. Or fuel supply is
no good because fuel line or injection
pipe leaks, pinched or pressed.
Check hose or fuel line. Replace fuel
filter.
Poor injection Check, replace injector.
Improper injection timing Check ECU.
Mechanical defect of engine Compression test, repair engine.
Defective supply pump
Let the engine at idle after replacing
pump.
Idle is improper or idle
speed is unstable or
irregular
Engine defect at high gear range Observe appropriate shift speed.
Engine temperature stays below
engine operation temperature.
Check rail pressure and cooling
system.
Replace thermostat.
Abnormal at max RPM Check and replace supply pump.
Defective Injection nozzle Check and repair or replace.
Improper injection timing Check ECU.
Exhaust system malfunction Check if deformed or clogged.
Mechanical defect of the engine Compression test, repair engine.
Defective supply pump Replace pump.
Exhaust gas (Black,
blue, white)
Non-input of QR code value
Check the input of QR code value.
Check if it matches the QR value on
the injector.
Accel pedal malfunction
- Check the history of trouble codes,
check rail pressure. (Target value,
Actual value)
- Input the improved ECU data
Defective max. rpm Check and replace supply pump
Air cleaner element polluted Clean or replace.
Fuel filter is clogged. Or fuel supply is
no good because fuel line or injection
pipe leaks, pinched or pressed. Or fuel
filter leaks
Check fuel line and hose, replace fuel
filter.
Air in the fuel system Air bleeding of fuel system
Defective injector nozzle Check, repair or replace.
Improper injection timing Check ECU.
Mechanical defect of engine Compression test, repair engine.
Engine lacks power,
acceleration is delayed
(Speedometer is normal,
no clutch slip)
Defective supply pump Check after replacing pump.