Fuel Injectors & Circuit
- To access fuel injectors, remove ignition wires. Remove hose from mass airflow sensor. Disconnect hose to fuel evaporative (frequency) solenoid valve at throttle body.
- Disconnect throttle position sensor and idle air control valve. Disconnect accelerator cable from throttle body. Disconnect and plug coolant hoses at throttle body.
- Disconnect hose from air intake heated tube. Detach fuel lines at cylinder head cover and remove from fuel rail. Disconnect vacuum hose from fuel pressure regulator. Remove intake manifold upper section. See Fig 1
.
- With intake manifold upper section removed, disconnect wiring harness from fuel injectors. Using a Digital Volt-Ohmmeter (DVOM) and test leads from Adapter Kit (VW 1594), check fuel injector resistance. See Fig 2
.
- Fuel injector resistance should be 15.0-21.5 ohms. If resistance is zero ohms, check for short circuit in wiring harness. If wiring harness is okay, replace fuel injector(s).
- With wiring harness and fuel injectors okay, disconnect ignition coil power output stage. Using test leads from adapter kit, check voltage supply to each injector by connecting LED tester between wiring harness connector terminals. See Fig 2
.
- Crank engine and observe LED tester. LED tester must flicker. If LED tester does not flicker, reconnect wiring harness connector(s) to fuel injector(s). Check for open circuit in wiring harness between fuel injector(s) and Engine Control Module (ECM).
- If LED tester flickers, remove fuel rail assembly (leaving fuel lines and injectors attached). Use test leads and fuel rail hose extensions if necessary. Disconnect Blue Engine Coolant Temperature (ECT) sensor. Connect the 15,000-ohm side of Adapter (VAG 1490) directly to ECT sensor wiring harness connector.
- Place injectors in Fuel Analyzer (VAG 1602). Crank engine and observe injectors. Injector spray pattern must be the same on all injectors. Turn ignition on for 5 seconds, and check fuel injectors for leaks. No more than 2 drops per minute are permissible. When reinstalling fuel rail, ensure "O" rings are not damaged.
Courtesy of VOLKSWAGEN UNITED STATES, INC.
Courtesy of VOLKSWAGEN UNITED STATES, INC.