Air/Fuel Mixture: Testing and Inspection

ENGINE TUNE-UP [ZM]
Engine Tune-up Preparation
1. Warm up the engine to normal operating temperature.
2. Shift the transaxle into neutral.
3. Turn off all electrical loads.
- Headlight switch
- Fan switch
- Rear window defroster switch
- A/C switch
4. Verify that the steering wheel is at straight ahead position.





5. Connect the SSTs (WDS or equivalent) to the DLC-2.
6. Access RPM PID.
7. Wait until the electrical fan stops.

Idle Mixture Inspection
1. Perform "Engine Tune-up Preparation".
2. Verify that the idle speed and ignition timing are within the specification.
3. Turn the test mode to OFF.
4. Warm up the engine by holding the engine speed at 2,500 - 3,000 rpm for approximately 3 min.
5. Insert an exhaust gas analyzer to the tailpipe.
6. Verify that the CO and HO concentrations are within the regulation.
- If not within the regulation, inspect the following:
- On-board diagnostic system
- HO2S
- Intake manifold vacuum
- Fuel line pressure
- Ignition timing control
- If the systems and devices are normal, replace the TWC.