DAF CF65, CF75, CF85 Series . Manual - part 411

©

 200416

5-1

Fuel system, XE/PE engine

DIAGNOSTICS

ΧΦ65/75/85 series

4

1

5. FUEL SYSTEM, XE/PE ENGINE

5.1 INTRODUCTION

If there is a fault in the system, it is usually 
detected by the electronic unit in the form of a 
fault code. This fault code can be read out using 
DAVIE. The fault-finding table contains possible 
causes of symptoms not detected by the 
electronic unit. 

DIAGNOSTICS

5-2

©

 200416

Fuel system, XE/PE engine

1

ΧΦ65/75/85 series

4

5.2 FAULT-FINDING TABLE

SYMPTOM: ENGINE CAN BE STARTED, BUT DOES NOT RUN

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Fuel fine filter/coarse filter clogged

Replace fuel fine filter and clean the system

No fuel supply/fuel lift pump defective; no delivery

Check:
-

the fuel level

-

the pipes for blockage and leaks

-

the fuel lift pump

-

the gallery pressure

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

SYMPTOM: ENGINE STALLS AND RUNS AGAIN AFTER RE-STARTING

Possible cause

Remedy

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

SYMPTOM: ENGINE STARTS POORLY

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Fuel fine filter/coarse filter clogged

Replace fuel fine filter and clean the system

Mechanical defect or clogging in pump units

Replace the pump units

Injectors defective

Check the injectors

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

Fuel lift pump delivery too low

Check: 
-

the fuel lift pump and replace if necessary

-

the gallery pressure

©

 200416

5-3

Fuel system, XE/PE engine

DIAGNOSTICS

ΧΦ65/75/85 series

4

1

SYMPTOM: ENGINE RUNS AT (INCREASED) IDLING SPEED AND DOES NOT RESPOND TO AC-

CELERATOR PEDAL

Possible cause

Remedy

Mechanical defect of accelerator pedal sensor

Check:
-

mechanical connection of sensor/accelerator 
pedal

-

accelerator pedal sensor

SYMPTOM: DIESEL KNOCK DURING ACCELERATION

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Injector defective

Check the injectors

SYMPTOM: IRREGULAR RUNNING OF ENGINE

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Fuel fine filter/coarse filter clogged

Replace fuel fine filter and clean the system

Mechanical defect or clogging in pump units

Replace the pump units

Injector defective

Check the injectors

Fuel lift pump delivery too low

Check:
-

the fuel lift pump and replace if necessary

-

the gallery pressure

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

SYMPTOM: REDUCED POWER AT ALL ENGINE SPEEDS

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Fuel fine filter/coarse filter clogged

Replace fuel fine filter and clean the system

Mechanical defect or clogging in pump units

Replace the pump units

Mechanical defect of accelerator pedal sensor

Check:
-

mechanical connection of sensor/accelerator 
pedal

-

accelerator pedal sensor

DIAGNOSTICS

5-4

©

 200416

Fuel system, XE/PE engine

1

ΧΦ65/75/85 series

4

Mechanical defect or clogging in pump units

Replace the pump units

Injector defective

Check the injectors

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

Fuel lift pump delivery too low

Check:
-

the fuel lift pump and replace if necessary

-

the gallery pressure

SYMPTOM: REDUCED POWER AT ALL ENGINE SPEEDS

Possible cause

Remedy

SYMPTOM: REDUCED POWER ABOVE A CERTAIN ENGINE SPEED

Possible cause

Remedy

Fuel fine filter/coarse filter partially clogged

Replace fuel fine filter and clean the system

Mechanical defect or clogging in pump units

Replace the pump units

Air leak in inlet system

Pressure-test the air inlet system

Pressure relief valve on pump housing does not 
shut off

Check the gallery pressure

Fuel lift pump delivery too low

Check:
-

the fuel lift pump and replace if necessary

-

the gallery pressure

SYMPTOM: WHITE/BLUE SMOKE IS EMITTED

Possible cause

Remedy

Poor fuel quality

Drain fuel, flush fuel system, replace the fuel filters 
and fill fuel tank with fuel

Air in fuel system

Check for drawing in of air:
-

via the suction pipe

-

via the seal of the fuel lift pump

Fuel fine filter/coarse filter clogged

Replace fuel fine filter and clean the system

Mechanical defect or clogging in pump units

Replace the pump units

Injector defective

Check the injectors

Fuel lift pump delivery too low

Check:
-

the fuel lift pump and replace if necessary

-

the gallery pressure

SYMPTOM: BLACK SMOKE IS EMITTED

Possible cause

Remedy

Injector defective

Check the injectors