Test NF-7A - Checking Oxygen (O2) Sensor Switching
WARNING:
High fuel pressure may be present in fuel lines. Open fuel system with caution. See FUEL PRESSURE RELEASE procedure.
- Allow engine to reach normal operating temperature. Using DRB-II, read O2 sensor state. If O2 sensor state is switching, system is functioning properly. Test is complete. If O2 sensor state is not switching, check if O2 sensor is locked on lean. If O2 sensor is locked on lean, go to TEST NF-7B. If O2 sensor is not locked on lean, turn engine off.
- Turn engine off. Remove upper half of intake manifold. Turn ignition on. Using DRB-II, actuate fuel system. Inspect injectors for fuel leakage. If injectors are leaking, replace leaking injectors or "O" rings as necessary. Perform VERIFICATION PROCEDURE VER-2.
- If injectors are not leaking, stop fuel system actuation. Turn ignition off. Reinstall upper half of intake manifold. Inspect air cleaner and inlet ducts for restrictions. Repair as required. Perform VERIFICATION PROCEDURE VER-2. If no restrictions are observed, go to TEST NF-15A.