Emission Control Systems: Testing and Inspection

CHECKING IDLE SPEED AND CO LEVEL

NOTE: Idle and CO level adjustment is no longer possible on vehicles fitted with a catalytic converter. The oxygen sensor is not disconnected during the idle CO test.

Test requirements
Engine in perfect mechanical condition. Loads must be switched off during the checks. Run check as quickly as possible to keep the intake ducts from heating up and causing faulty CO level readings. Ambient temperature 15.35 deg. C. (60°F)




1. Fit exhaust gas adapter to test connector of catalytic converter.




2. Warm up engine to operating temperature (70...90°C (158 - 194°F) oil temperature).

3. Do not disconnect oxygen sensor connector. Connect CO meter and additional rev counter to manufacturer's instructions.

CO check value: O.4 - 1.2%
Idle speed: 800 ± 40 rpm