A8 Sedan V8-3.7L (AEW) (1997)
Fuel Injector: Testing and Inspection
Fuel Injection Volume, Leakage and Spray Pattern, Checking
Fuel Injection Volume, Fuel Injector Leakage And Spray Pattern, Checking
Requirements
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Fuel pressure OK
Preparation
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Remove intake air duct between air cleaner housing and throttle valve.
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Remove engine cover.
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Remove accelerator pedal cable at bracket.
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Remove ball joint at connecting linkage for cruise control.
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Move accelerator pedal cable over cruise control vacuum unit toward rear.
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Disconnect vacuum hose for cruise control vacuum unit.
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Disconnect vacuum hose from fuel pressure regulator.
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Disconnect harness connector for engine coolant temperature sensor (blue connector).
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Disconnect harness connectors for knock sensors.
Remove cable ties or retaining straps as necessary.
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Disconnect connector for Intake Manifold Tuning (IMT) valve.
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Disconnect harness connector for air control valve for fuel injectors.
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Disconnect harness connectors from fuel injectors.
Remove cable ties or retaining straps as necessary.
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Remove fuel rail from intake manifold and lift off together with fuel injectors.
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Disconnect hose from air control valve for fuel injectors.
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Connect VAG1598/19 test box to wiring harness connector for Engine Control Module (ECM).
Checking fuel injector leakage
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Using adapter cables from VAG1594 connector test kit, connect jumper wire between VAG1598/19 test box terminals D11 and A4 (to actuate fuel
pump relay).
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Switch ignition on.
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Visually check fuel injectors for leaks.
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With the fuel pump running, no more than 1 to 2 drops per minute may drip from the fuel injectors.
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Switch ignition off.
If fuel leakage is greater than 1 to 2 drops per minute:
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Stop fuel pump (disconnect jumpered connection on VAG1598/19 test box) and replace faulty injector(s).
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Install fuel rail.
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Check readiness code. If DTC memory has been erased, generate new readiness code.
Checking fuel injection volume
NOTE: Before removing fuel injectors, release fuel pressure by briefly opening and closing fuel filler cap.
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Remove fuel rail
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Insert fuel injector to be tested into measuring container from VAG1602 fuel analyzer.