S6 V8-4.2L (BBD) (2004)
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Fuel Injector: Testing and Inspection
With Manufacturer's Scan Tool
Injection quantity, leakage and spray pattern of injectors, checking
Test conditions
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Fuel pressure OK
Removing fuel manifold tube
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Remove engine compartment cover.
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Remove connecting pipe between air cleaner housing and throttle valve body.
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Disconnect vacuum hose from fuel pressure regulator.
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Separate connectors for knock sensors and remove cable ties as necessary.
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Disconnect solenoid valve for secondary air injection from fuel manifold tube.
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Disconnect connectors from injectors and remove cable ties as necessary.
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Unbolt fuel manifold from variable intake manifold and pull it upward and off intake manifold together with injectors.
Checking injectors for leaks
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Place injector to be tested in a measuring glass from injection quantity tester VAG 1602.
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Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. See: Computers and Control
Systems/Testing and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/With Manufacturer's Scan Tool/Scan Tool Connecting and
Initial Checks/Connecting VAG 1598/31 Test Box
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Bridge contacts 1 and 65 on test box using test leads from adapter set VAG 1594 A (this creates a Ground connection to one side of fuel pump
relay coil).
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Switch 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 Ground voltage supply for the fuel pump relay comes
via the cable bridge in the test box.
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Check injectors for leaks (visual check). When fuel pump is running, only 1 or 2 drops a minute should escape from each injector.
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If fuel loss is greater than this, switch off fuel pump (switch off ignition) and replace faulty injector.
Checking injection quantity
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Place injector which is to be tested into measuring glass of injection quantity tester VAG 1602.
