DAF 95XF. Manual - part 384

4

DIAGNOSIS

XF engine brake

95

XF series

4-2

FAULT: DEB REMAINS ENGAGED

Possible cause

Remedy

Elektrische storing.

Check electrical circuit.

Magnetic valve mechanically blocked.

Check magnetic valve.

Damaged magnetic valve sealing rings.

Replace all magnetic valve sealing rings.

FAULT: DEB OPERATES IRREGULARLY

Possible cause

Remedy

Electrical fault.

Check electrical circuit.

Incorrect setting of DEB clearance.

Check DEB setting.

Main piston stuck in DEB housing.

Check free movement of main piston.

Operating piston stuck in DEB housing.

Check free movement of operating piston.

Damaged magnetic valve sealing rings.

Replace all magnetic valve sealing rings.

Magnetic valve oil strainer is blocked.

Clean magnetic valve oil strainer.

Control valve stuck in DEB housing.

Check free movement of control valve.

Defective control valve.

Check the operation of the control valve.

Lubricating oil too thick.

Run the engine at operating temperature.

Lubricating oil diluted with fuel.

Check lubricating oil for dilution.

Air bubbles in the oil.

Check the engine’s oil level/oil specification.

Oil duct plugs in DEB housing.

Clean/replace plugs.

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4

95

XF series

XE engine fuel system

DIAGNOSIS

5-1

5.  XE ENGINE FUEL SYSTEM

5.1

FAULT-FINDING TABLE

FAULT: ENGINE CAN BE STARTED, BUT DOES NOT RUN

Possible cause

Remedy

Poor fuel quality.

Poor fuel quality.

Air in the fuel system.

Check the fuel system for drawing in air:
-

through suction pipe

-

through sealing ring of fuel lift pump.

Fuel fine filter/fuel coarse filter blocked.

Replace the fuel fine filter and clean the system.

Incorrect pump housing camshaft timing,
camshaft position sensor signal not present at
correct moment.

Check timing/signal from camshaft position
sensor.

No fuel supply/fuel lift pump defective, no output.

Check:
-

fuel level

-

pipes for clogging and leakage

-

fuel lift pump

-

gallery pressure.

Pressure-relief valve on pump housing does not
shut off.

Check gallery pressure.

Fault in electrical components/wiring of:
-

connectors

-

pump unit

-

electronic unit

-

crankshaft position sensor and camshaft
position sensor.

Check the electrical system.

FAULT: ENGINE STALLS AND PICKS UP AFTER RESTARTING

Possible cause

Remedy

Air in the fuel system.

Check the fuel system for drawing in air:
-

through suction pipe

-

through sealing ring of fuel lift pump.

Pressure-relief valve on pump housing does not
shut off.

Check gallery pressure.

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4

DIAGNOSIS

XE engine fuel system

95

XF series

5-2

FAULT: ENGINE DOES NOT PICK UP PROPERLY

Possible cause

Remedy

Poor fuel quality.

Drain fuel, rinse the fuel system, replace the fuel
filters and fill the fuel tank with fuel.

Air in the fuel system.

Check the fuel system for drawing in air:
-

through suction pipe

-

through sealing ring of fuel lift pump.

Fuel fine filter/fuel coarse filter blocked.

Replace the fuel fine filter and clean the system.

Connection points on pump units changed.

Install the correct connection points on the
correct pump unit.

Mechanical defect or clogging of pump units.

Replace the pump units.

Injectors defective.

Check the injectors.

Pressure-relief valve on pump housing does not
shut off.

Check gallery pressure.

Fuel lift pump output too low.

Check:
-

the fuel lift pump and replace, if necessary

-

gallery pressure.

Fault in electrical components/wiring of:
-

connectors

-

crankshaft position sensor

-

sensor for engine coolant temperature

-

pump unit

-

camshaft position sensor.

Check the electrical system.

FAULT: ENGINE RUNS AT (INCREASED) IDLING SPEED AND DOES NOT RESPOND TO

ACCELERATOR PEDAL

Possible cause

Remedy

Accelerator pedal sensor, mechanical defect.

Check:
-

mechanical connection sensor/accelerator
pedal

-

accelerator pedal sensor.

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4

95

XF series

XE engine fuel system

DIAGNOSIS

5-3

FAULT: DIESEL KNOCK DURING ACCELERATION

Possible cause

Remedy

Poor fuel quality.

Drain fuel, rinse the fuel system, replace the fuel
filters and fill the fuel tank with fuel.

Air in the fuel system.

Check the fuel system for drawing in air:
-

through suction pipe

-

through sealing ring of fuel lift pump.

Injector defective.

Check the injectors.

Fault in electrical components/wiring of:
-

sensor for engine coolant temperature

-

crankshaft position sensor.

Check the electrical system.

FAULT: ENGINE RUNS IRREGULARLY

Possible cause

Remedy

Poor fuel quality.

Drain fuel, rinse the fuel system, replace the fuel
filters and fill the fuel tank with fuel.

Air in the fuel system.

Check the fuel system for drawing in air:
-

through suction pipe

-

through sealing ring of fuel lift pump.

Fuel fine filter/fuel coarse filter blocked.

Replace the fuel fine filter and clean the system.

Connection points on pump units changed.

Install the correct connection points on the
correct pump unit.

Mechanical defect or clogging of pump units.

Replace the pump units.

Injector defective.

Check the injectors.

Fuel lift pump output too low.

Check:
-

the fuel lift pump and replace, if necessary

-

gallery pressure.

Pressure-relief valve on pump housing does not
shut off.

Check gallery pressure.

Fault in electrical components/wiring of:
-

pump unit

-

accelerator pedal sensor

-

sensor for engine coolant temperature

-

boost pressure sensor

-

fuel temperature sensor

-

connectors.

Check the electrical system.

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