DAF 95XF. Manual - part 389

4

XF ENGINE FUEL SYSTEM

Inspection and adjustment

95

XF series

3-4

3.2

CHECKING THE FUEL LEVEL ELEMENT

To avoid deforming the fuel tank,
the pressure in the fuel tank may
not exceed 0.4 bar.

1.

Fit a pressure reducing valve connection to
a fuel filler cap (without bleeding) and
connect it to the fuel tank.

2.

Pressurise the fuel tank (maximum 0.2 bar).

3.

Slowly increase the pressure, until one can
hear the system blow off via the small
overpressure valve and check the opening
pressure of the fuel level element, see main
group “Technical data”.

4.

Depressurise the fuel tank and remove the
fuel-tank cap with air connection.

5.

Note:
To prevent dirt from entering, first clean the
exterior of the fuel tank.

Remove the fuel level element.

6.

Check the angular rotation of the fuel level
element, see main group “Technical data”.

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95

XF series

Inspection and adjustment

XF ENGINE FUEL SYSTEM

3-5

3.3

INSPECTION AND ADJUSTMENT OF INJECTOR OPENING PRESSURE

Fuel or test fluid discharged by an
injector may penetrate the skin and
be very harmful to your health.
Make sure the fuel jet is discharged
into a suitable container.

Checking the opening pressure with an
injector test pump
-

The opening pressures of the injectors can
be tested using an injector test pump
(DAF no. 0694966). The advantage of this
method is that the injectors need not be
removed from the engine.

Instructions for the use of the injector test
pump
Before the injector testing pump is used, it must
first be bled.
1.

Remove the pump reservoir filler cap and fill
the reservoir with test fluid. The fluid level
must be approximately 1 cm beneath the
top rim.

2.

Tilt the pump until the line with the word
“BLEED” is in a horizontal position.

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4

XF ENGINE FUEL SYSTEM

Inspection and adjustment

95

XF series

3-6

3.

Depress the bleed pin (1) and
simultaneously turn the crank (2) clockwise
to the stop.
During this operation, air bubbles will come
to the surface in the reservoir. Now turn
back the crank, fill the reservoir again and
turn the crank until no more air bubbles
come to the surface.
Now release the bleed pin. Continue turning
the crank until fuel escapes on the delivery
side.

4.

If necessary, fill the fuel reservoir and screw
back the cap.

5.

The pump is now ready for use.

Inspecting the injector opening pressure
1.

Remove the injection lines in sets of three,
see chapter “Removal and installation”.
Immediately plug the connection openings
on the fuel pump.

2.

Connect the injection line (supplied with the
injector test pump) to the injector to be
tested and to the test pump. Keep the test
pump approximately in horizontal position.

3.

Loosen the test pump filler cap by half a
turn, so that air can enter the reservoir.

4.

Turn the crank of the test pump clockwise.
The compression stroke starts. Watch the
fluid level in the test pump.

5.

Carefully determine the opening pressure of
the injector. There is no harm in repeating
the test twice or three times. If the test is
repeated too often however, the test fluid
deposited on the piston may cause damage
to the engine when it is started.

6.

Reinstall the injection lines after the
injector(s) has (have) been tested, see
chapter “Removal and installation”.

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95

XF series

Inspection and adjustment

XF ENGINE FUEL SYSTEM

3-7

Adjusting the injector opening pressure

Note:
The test pump can also be used to test injectors
outside the engine. The bottom of the test pump
can be clamped in a vice without causing
damage to the test pump.

1.

Remove the injector, see chapter “Removal
and installation”.

2.

Disassemble the injector, see chapter
“Disassembly and assembly”.

3.

Adjust the opening pressure by fitting a
thicker or thinner shim (1). For pressure
settings, see main group “Technical data”.

Note:
An increased shim thickness of 0.01 mm
raises the pressure by approx. 1.5 bar.

4.

Assemble the injector, see chapter
“Disassembly and assembly”.

5.

Fit the injector, see chapter “Removal and
installation”.

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