Test NTC-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
in this article.
- Allow engine to reach normal operating temperature. Using DRB, read O2 sensor state. If O2 sensor state is switching, system is functioning okay. 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 NTC-7B. If O2 sensor is not locked on lean, turn engine off.
- Release fuel pressure. Install fuel pressure gauge in fuel supply line. Turn ignition on. Using DRB, actuate fuel system. Allow fuel pressure gauge to stabilize to normal fuel pressure. Stop fuel system actuation. Monitor fuel pressure gauge for one minute.
- If fuel pressure gauge reading drops more than 10 psi (0.7 kg/cm2 ), replace leaking injectors or "O" rings as necessary. Perform TEST VER-2 . If fuel pressure gauge reading does not drop more than 10 psi (0.7kg/cm2 ), go to next step.
- Inspect air cleaner and inlet ducts for restrictions. Repair as necessary. Perform TEST VER-2. If no restrictions are present, go to TEST NTC-14A .