Measure the concentration of carbon monoxide (CO) and the concentration of hydrocarbons (CH) at idle speed without load.
Make sure the engine speed is normal.
Before taking measurements, please perform the following checks:
1) Condition of the air cleaner filter element.
2) Ignition timing angle.
3) Condition of spark plug electrodes.
4) Condition of the crankcase ventilation system.
5) Status of the PGM-Fi indicator lamp (should not be lit).
1. Start the engine and warm it up until the radiator fan runs twice. Then warm it up for another 2 minutes without load at 3000 rpm.
2. Make sure that the idle speed is within the norm and measure the concentration of carbon monoxide (CO) and the concentration of hydrocarbons (CH).
- Concentration (CO) at idle speed: below 0.1%
- Concentration (CH) at idle speed: below 100 ppm
3. If the CO and CH content is higher than the permissible value, check the catalytic converter (see chapter Mechanical part of the engine) and the engine control unit (see above).