Checking concentration of emissions

CHECKING CONCENTRATION OF EMISSIONS

The system operates without the possibility of adjusting the advance, the carbon monoxide (CO) content and the idle air flow rate therefore no manual adjustments whatsoever are necessary. However, a check on the content of the exhaust gases upstream and downstream of the catalyzer can provide precious indications on the operating conditions of the injection/ignition system, the engine parameters and the catalyzer.

Checking idle concentration of CO and HC upstream of the catalytic silencer

To check the concentration of carbon monoxide (CO) and unburnt hydrocarbons (HC) upstream of the catalyzer, proceed as follows:

1. Undo the cap located on the exhaust pipe, upstream of the catalyzer, and tighten the tool in its place.
2. Connect the sensor for a suitably calibrated CO-tester to the tool.
3. Start up the engine and let it reach operating temperature.
4. Check that the idle speed is the one planned.
5. Check that the idle concentration of CO is within the recommended values (see table); if this is not the case, it is necessary to check:
   • that the Lambda sensor is working properly using the F/L Tester;
   • for the presence of air penetration in the area surrounding the Lambda sensor housing;
   • the injection and ignition system (in particular the wear of the spark plugs).
6. Check, under the same circumstances, that the concentraion of HC is not less than 500 p.p.m.
7. If these values are not measured, check the engine paying particular attention to:
   • the timing;
   • the engine compression;
   • the valve clearance.

Table summarizing pollutant emission tolerance values