Checking injection quantity, absence of leaks and spray pattern of injectors — AUDI

AQJ ASG ANK
Test conditions

Fuel pressure OK

Removing fuel manifold tube

Remove engine compartment cover.
Remove connecting pipe between air cleaner housing and throttle valve body.
Disconnect vacuum hose from fuel pressure regulator.
Separate the connectors for the knock sensors and remove cable ties as necessary.
Detach solenoid valve for secondary air inlet from fuel manifold tube.
Unplug the connectors from the injectors and remove cable ties as necessary.
Unbolt the fuel manifold from the variable intake manifold and pull it upwards and off the intake manifold together with the injectors.

Checking injectors for leaks

Place injector to be tested in a measuring glass from injection quantity tester V.A.G 1602.
Connect test box V.A.G 1598/31 to wiring harness for engine control unit; do not connect the engine control unit => Page
24-12
.
Bridge contacts 1 and 65 on the test box using test leads from adapter set V.A.G 1594 A (this creates an earth connection to one side of the fuel pump relay coil).
Switch the ignition on.

Note:

Once the ignition has been switched on, the fuel pump runs continuously even if the engine is not running. This is because with the ignition is switched on, the fuel pump relay receives its positive voltage supply via the engine electrics. The earth voltage supply for the fuel pump relay comes via the cable bridge in the test box.

Check injectors for leaks (visual check). When the fuel pump is running, only 1 or 2 drops a minute should escape from each injector.
If the fuel loss is greater than this, switch off the fuel pump (switch off ignition) and renew faulty injector.

Checking injection quantity

Place the injector which is to be tested into measuring glass of injection quantity tester V.A.G 1602.

Connect one of the injector contacts to the engine earth using a test cable and crocodile clip from V.A.G 1594 A.
Connect second contact of injector with remote control V.A.G 1348/3A, adapter lead V.A.G 1348/3-2 and auxiliary cable to positive.
Switch the ignition on.
The fuel pump should run.

Activate remote control V.A.G 1348/3A for 30 seconds.
Perform measurements on all injectors.
Once all four injectors have been actuated, place measuring glasses on a level surface.

Specification per injector:

A6 models · S6 models
95 ... 115 ml · 105 ... 125 ml

If the specified result is not attained for all injectors:

Check fuel pressure => Page
24-39
.

If the specified results are not attained for one injector:

Replace the relevant injector.

Note:

When checking the injection quantity, also check the spray pattern. The spray pattern should be the same for all the injectors.

Installation of the fuel manifold together with injectors is performed in the reverse sequence. The following points should be noted when installing:

Renew the O-rings at all opened connections. (when renewing the front O-ring, ensure that the plastic cap is not removed from the injector head. The O-ring must be pulled off over the plastic cap).
Coat the O-rings with clean engine oil.
Check to make sure that the retainer clamps are properly seated.