Setting up Idle valve duty cycle



NOTE-1:The following guide is for stock or lightly modified engines

NOTE-2:Before the idlle speed setting,check the following items:

  • The Check Engine light has not been reported on
  • Ignition TIming
  • Spark Plugs
  • Air Cleaner
  • PCV system


1.Start the engine. Hold the engine at 3000 rpm with no load until the radiator fan comes one, then let it idle.

2. Disconnect the 2P connector from the IACV.

3. Start the engine with the accelarator pedal slightly depressed.Stabilize the engine speed at 1000, then slowly release the pedal until the engine idles.

4.Check idling in no-load conditions: headlights, blower fan, rear defogger, cooling fan and air conditioner are not operating.

Idle speed should be:

between 370 to 470 rpm.

Adjust the idle speed, if necessary, by turning the idle adjusting screw.

5.Turn the ignition switch OFF.

6. Reconnect the 2P connector on the IACV.

7. Adjust the IACV duty until you reach the Target RPM.

8.Restart the engine with no-load conditions for one minute, then check the idle speed.

9.Idle the engine for one minute with headlights (Low) ON and check idle speed.

10. Turn the headlight off. Idle the engine for one minute with heater fan switch at HI and air conditioner on, then check the idle speed.