1. Adjusting the idle speed with quantity and quality screws.
Start the engine. Using a gas analyzer and turning the quantity screw and the quality screw, achieve the required CO concentration level at a given idle speed (for normal idle speed values see above).
2. Measure the CO concentration.
Let the engine run for about 3 minutes at 2500 rpm, then switch it to normal idle speed. Install the gas analyzer intake 40 cm deep into the exhaust pipe. Measure the CO concentration at idle speed, after the speed has stabilized.
- For 2Y-C (U) and 3Y-C (U) engines - 1.5% or less
If the CO concentration is outside the permissible range, turn the screws to achieve the required level.
If the required CO concentration cannot be achieved, see the table below for troubleshooting possible faults.
3. (If there is a feedback system)
Connect the vacuum hose to the vacuum tester (VTV).
4. (If there is an air bypass system in the exhaust pipe (AS-systems))
Connect the vacuum hose to the AS system vibration valve.
5. (If the idle speed screw is sealed)
After completing the adjustment, install a new (blue) plug (seal) on the idle speed screw.
6. After completing the adjustment, perform a road test to ensure that engine performance has not changed.