Testing injection rate, leakage and spray pattern of injectors — AUDI

AEW AHC AKG AKJ AKH
Test conditions

Fuel pressure OK

Remove fuel rail

Remove connecting pipe between air cleaner housing and throttle housing.
Remove engine compartment cover.
Disengage throttle cable from support bracket.
Disengage ball head from CCS linkage.
Lay throttle cable toward rear over CCS vacuum unit.
Detach vacuum hose from CCS vacuum unit.
Detach vacuum hose from fuel pressure regulator.

Disconnect connectors for knock sensors and remove cable ties where necessary.
Detach connector from coolant temperature sender (blue connector).
Detach connector from intake manifold change-over valve.
Detach connectors from injectors and remove cable ties where necessary.
Unscrew fuel rail from intake manifold and pull fuel rail upwards off manifold together with injectors.
Connect test box V.A.G 1598/19 to engine control unit wiring harness=>Page
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Connect contact D11 on test box to contact A4 with leads from auxiliary test set V.A.G 1594 (activates fuel pump relay).

Switch on ignition.
Check injectors for leakage (visual check).

With the fuel pump running, not more than 1 - 2 drops per minute should emerge from each injector.

Switch off ignition.
If a greater amount of fuel comes out, switch off fuel pump (remove jumper on test box V.A.G 1598/19) and renew defective injector.
Install fuel rail=>Page
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Testing injection rate

Note:

Before removing an injector, release the fuel pressure by briefly opening the fuel tank cap.

Remove fuel rail=>Page
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Insert injector to be tested into measuring glass of injection rate tester V.A.G 1602.
Switch on ignition.
Connect contact D11 on test box V.A.G 1598/19 to contact A4 with leads from auxiliary test set V.A.G 1594 (actuates fuel pump relay).
Connect contact A2 on test box V.A.G 1598/19 to contact E7 with leads from auxiliary test set V.A.G 1594 (actuates current supply relay for Motronic for positive supply to injectors).

To check right-side cylinder bank, attach connector from cylinder 1 injector to injector to be tested.
To actuate an injector in right-side cylinder bank (bank 1), connect contact E11 (earth) on test box V.A.G 1598/19 to contact E1 with leads from auxiliary test set V.A.G 1594 for 30 seconds.

Specified value: 105 - 115 ml

To check left-side cylinder bank, attach connector from cylinder 5 injector to injector to be tested.
To actuate an injector in left-side cylinder bank (bank 2), connect contact E11 (earth) on test box V.A.G 1598/19 to contact E5 with leads from auxiliary test set V.A.G 1594 for 30 seconds.

Specified value: 105 - 115 ml

Switch off ignition.

If measured value of one or more injectors is outside tolerance, switch off fuel pump and current supply relay (remove jumper on test box V.A.G 1598/19) and renew defective injector.
Install fuel rail=>Page
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Note:

Before removing an injector, release the fuel pressure by briefly opening the tank cap.

If the measured values of all the injectors are outside the tolerance, check the fuel pressure=>Page
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Note:

When testing the injection rate, the spray pattern must also be checked. The spray pattern must be the same for all injectors.

Installing fuel rail

The fuel rail and injectors are reinstalled as they were removed, in reverse order. Observe the following points:

Renew O-rings on all opened connections. (Never remove plastic cap from injector head to renew front O-ring; lift O-ring over plastic cap instead).
Coat O-rings with clean engine oil.
Push injectors vertically into fuel rail as far as possible in correct position (electrical connections face outward) and secure with retaining clips.
Mount fuel rail with secured injectors on intake manifold and press in evenly as far as possible.
Position mounting screws, turn fuel rail slightly by hand in direction of intake manifold and tighten mounting screws (10 Nm).
Check correct installation position of injectors.

(electrical connections face outward)

Check proper seating of retaining clips.