Auxiliary Air Valve System
NOTE:
Install tachometer when checking auxiliary air valve system. Ensure tachometer is connected to proper terminals. See IDLE SPEED & MIXTURE in ADJUSTMENTS
article for tachometer connections.
CAUTION:
Some tachometers may not be compatible with ignition system. Consult tachometer manufacturer before connecting tachometer to system. To avoid possible damage to ignitor and/or coil, DO NOT allow tachometer terminal to become grounded.
- Install tachometer. With engine coolant less than 176°F (80°C), remove air intake hose from throttle body.
- Start engine. Place finger over air valve port to block airflow. See Fig 1. Engine speed should decrease noticeably. Remove finger from air valve port.
- Allow engine to warm to normal operating temperature. Place finger over air valve port to block airflow. Engine speed should not decrease more than 100 RPM for Tercel or 50 RPM for all others.
- If engine RPM does not respond as indicated, check for vacuum leaks or restricted chamber in auxiliary air valve circuit. If no defects are found, replace auxiliary air valve.