IDLE SPEED ADJUSTMENT
See Figure 1
Idle speed is controlled automatically by the ECU through the Idle Speed Control (ISC) solenoid valve. Idle speed adjustment is usually not necessary.
- Check the ignition timing and adjust to specification, if necessary.
- Turn off all lights and other unnecessary electrical loads. Idle speed adjustment must be done while the radiator cooling fan is not operating.
- Set the parking brake and place the transaxle selector lever in neutral on manual transaxle vehicles or P on automatic transaxle vehicles. Warm up the engine.
- On all engines except 1995-98 2.0L (FS) engines with automatic transaxle, connect a jumper wire between the TEN terminal and the GND terminal at the underhood test connector.
- On 1995-98 2.0L (FS) engines with automatic transaxle, remove the shorting bar from the double wire SPOUT connector.
- Attach a suitable tachometer according to the manufacturer's instructions.
- Check the idle speed. It should be within specifications.
- If the idle speed is not correct, adjust the idle speed by turning the air adjusting screw.
- After adjusting the idle speed, disconnect the jumper wire from the test connector or install the shorting bar.
- Remove the tachometer from the engine.
On all Mazda engines, the air/fuel mixture is controlled by the Electronic Control Unit (ECU), therefore no idle mixture adjustment is possible or necessary.