Checking and adjusting injectors: Audi 2.4 D (AAS)

Injector removed =>Page
23-37
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Special tools and workshop equipment required

Injector tester V.A.G 1322 with pressure line V.A.G 1322/2

Checking injector needle spray pintles (visual check)

Check the spray pintle for damage (broken or bent).
Replace the injector as necessary.

Checking spray pressure

Test requirements:

Injector fastened to injector tester.

Important
When testing injectors, care should be taken to ensure that the jet of fuel does not come into contact with the hands, as the high pressure will cause the fuel to penetrate the skin which could cause severe injuries.
Open the valve to pressure gauge on V.A.G 1322.
Slowly press hand lever downwards. Read spray pressure upon commencement of spray:

Specified value · Wear limit
130...138 bar · 120 bar

If specified value is not attained:

Adjust the spray pressure => Page
23-51
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Checking for leaks

Test requirements:

Injector fastened to injector tester.

Open the valve to pressure gauge on V.A.G 1322.
Press pump lever slowly downwards and maintain approx. 110 bar for 10 seconds.
No fuel must leak from the nozzle opening

Replace the injector as necessary.

Checking spray pattern

Test requirements:

Injector fastened to injector tester.

Close the valve to pressure gauge on V.A.G 1322.
Slowly depress the pump lever using brief, rapid downward strokes (4...6 strokes/second).
The injector spray pattern must resemble a closed cone as closely as possible
The injector must not drip after spraying - the spray must cease at once.
The injector must issue a brief chattering sound when the fuel escapes.

Replace the injector as necessary.

Dismantling and assembling injector

Clamp upper part of injector in vice and loosen threaded connection.
Clamp lower part of injector in vice to prevent individual components from falling apart, and dismantle injector.

When dismantling the injector make sure that the individual parts are not interchanged.

1 -
Injector, upper part
2 -
Shim
3 -
Injector spring
4 -
Pressure pin
5 -
Injector holder insert
6 -
Injector needle
7 -
Injector body
8 -
Injector, lower part
9 -
Heat insulation seal

Note:

To avoid corrosion caused by sweat from technician's hands the injector must be installed in the engine and operated immediately following assembly. If this is not possible the injector must be flushed once with pressurised fuel on the V.A.G 1322 tool.

Tightening torque

Component · Nm
Upper part of injector to lower part of injector · 70

Adjusting spray pressure

Injector dismantled =>Page
23-49
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For adjustment purposes, shims of thicknesses from 1.00...1.95 mm are available. Part numbers

=> Parts List

Note:

Shim sizes are staggered in thickness intervals of 0.05 mm. Use the storage box 3065 for purposes of storing the shims.

A thicker shim increases the spray pressure.
A thinner shim lowers the spray pressure.
Increasing the preload by 0.05 mm increases the spray pressure by approx. 5.0 bar.

Note:

When repairing used injectors, the spray pressure must be adjusted to the specified value for new injectors.

Following assembly:
Checking spray pressure =>Page
23-47
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Checking injector spray pattern => Page
23-48
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