DAF 95XF. Manual - part 426

4

XE ENGINE INLET/EXHAUST SYSTEM

Inspection and adjustment

95

XF series

3-4

3.4

INSPECTION OF INLET UNDERPRESSURE

1.

Remove the connection of the
underpressure sensor (A) from the inlet pipe
between the air cleaner housing and the
turbocharger.

2.

Connect a pressure gauge with a maximum
rating of –100 mbar (–10 kPa) to the
connection of the underpressure sensor.

3.

Measure the inlet underpressure at the
maximum loaded engine speed and
compare the measurement result with the
specified value. See main group “Technical
data”.

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A

3.5

 INSPECTION OF BOOST PRESSURE

To obtain a better indication of where the
problem occurs, the gallery pressure, the inlet
underpressure and the exhaust back pressure
can be measured at the same time as the boost
pressure.

Drive the same route each time to obtain as
good a picture as possible.

Turbocharger with wastegate
When you measure the boost pressure curve of
a vehicle fitted with a turbocharger with
wastegate, the air hose between the
electro-pneumatic boost pressure valve and the
diaphragm must not be disconnected.

1.

DAVIE can be used for measuring the boost
pressure.

2.

The weight of the vehicle should
approximate the maximum combination
weight.

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4

95

XF series

Inspection and adjustment

XE ENGINE INLET/EXHAUST SYSTEM

3-5

3.

Run the engine at operating temperature
(drive for at least 15 minutes with a loaded
vehicle).

4.

Select the highest gear but one.

5.

In this gear, apply full throttle from 800 rpm.

6.

Note, from 900 rpm, the boost pressure per
100 rpm.

7.

Perform this measurement at least three
times and take the mean values.

8.

Plot a graph on the test sheet with the mean
values found.

Note:
The shape of the curve is important. The
exact value is of less importance.

Checking procedure following plotting of a
boost pressure curve
-

Check the fuel system for the presence of
air.

-

Replace/clean the air filter element.

-

Check the setting of the wastegate on the
turbocharger (if present).

-

Check the exhaust brake butterfly valve for
correct operation.

-

Check the charge cooler exterior for dirt
deposits.

-

Visually check the low-pressure fuel pipes
for leaks and correct installation.

-

Clean the water separator (if fitted).

-

Replace the fuel filter.

-

Clean the fuel coarse filter.

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4

XE ENGINE INLET/EXHAUST SYSTEM

Inspection and adjustment

95

XF series

3-6

-

Check the suction pipe of the tank for
clogging by large pieces of foreign matter.

-

Check the fuel tank for contamination.
Clean the tank with a steam cleaner, if
necessary.

-

Check the air inlet system for any leaks.

-

Check the exhaust system for any leaks.

-

Check the exhaust system for blockages by
measuring the exhaust back pressure.

-

Check the turbocharger wheels on the
compressor and turbine side for damage
and for deposits of salt or any other
contaminants.

-

Check the valve and DEB play.

-

Check the injection lines for damage.

-

Check the fuel pressure on the on the
low-pressure side.

-

Check whether components of the right type
have been fitted (turbocharger, injectors
etc.).

-

Check the opening pressure of the injectors.

-

Clean the nozzle openings using calibrated
injector needles (DAF no. 1329371).

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4

95

XF series

Removal and installation

XE ENGINE INLET/EXHAUST SYSTEM

4-1

4.  REMOVAL AND INSTALLATION

4.1

REMOVAL AND INSTALLATION OF TURBOCHARGER

If the turbocharger to be replaced
was damaged to such an extent that
parts of the turbocharger are
missing or that lubricating oil has
entered the inlet system, the inlet
and exhaust systems must be
cleaned and inspected thoroughly
in order to prevent serious damage
to the engine.

Removing the turbocharger
1.

Remove the heat shields (1) from the
turbocharger.

2.

Remove the air inlet hose (2) between the
turbocharger and the air filter.

3.

Remove the exhaust brake (3).

4.

Disconnect the connector pipe (4) from the
turbocharger and the air inlet pipe to the
intercooler.

5.

Remove the turbocharger lubricating pipes.
Plug the openings.

6.

Remove the fixing nuts from the
turbocharger.

7.

Remove the turbocharger from the exhaust
manifold.

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1

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