Document ID: chunk:federal_register_of_legislation:F2024L00443:reg:55:p2
Version: federal_register_of_legislation:F2024L00443
Segment Type: reg
Provision Reference: reg 55 (pt 2/4)
Character Range: 206296–209529

the "neutral" position and with the clutch engaged.
              2.4. In the case of vehicles with automatic-shift gearboxes, the test shall be carried out with the gear selector in either the "neutral" or the "parking" position.
              2.5. Components for adjusting the idling speed
              2.5.1. Definition
               For the purposes of this Regulation, "components for adjusting the idling speed" means controls for changing the idling conditions of the engine which may be easily operated by a mechanic using only the tools described in paragraph 2.5.1.1. of this annex. In particular, devices for calibrating fuel and air flows are not considered as adjustment components if their setting requires the removal of the set-stops, an operation which cannot normally be performed except by a professional mechanic.
              2.5.1.1. Tools which may be used to control components for adjusting the idling speed: screwdrivers (ordinary or cross-headed), spanners (ring, open-end or adjustable), pliers, Allen keys.
              2.5.2. Determination of measurement points
              2.5.2.1. A measurement at the setting in accordance with the conditions fixed by the manufacturer is performed first;
              2.5.2.2. For each adjustment component with a continuous variation, a sufficient number of characteristic positions shall be determined.
              2.5.2.3. The measurement of the carbon-monoxide content of exhaust gases shall be carried out for all the possible positions of the adjustment components, but for components with a continuous variation only the positions defined in paragraph 2.5.2.2. of this annex shall be adopted.
              2.5.2.4. The Type 2 test shall be considered satisfactory if one or both of the two following conditions is met:
              2.5.2.4.1. None of the values measured in accordance with paragraph 2.5.2.3. of this annex exceed the limit values set out in paragraph 5.3.2.2. of this Regulation;
              2.5.2.4.2. The maximum content obtained by continuously varying one of the adjustment components while the other components are kept stable does not exceed the limit value, this condition being met for the various combinations of adjustment components other than the one which was varied continuously.
              2.5.2.5. The possible positions of the adjustment components shall be limited:
              2.5.2.5.1. On the one hand, by the larger of the following two values: the lowest idling speed which the engine can reach; the speed recommended by the manufacturer, minus 100 revolutions per minute;
2.5.2.5.2. On the other hand, by the smallest of the following three values:
               The highest speed the engine can attain by activation of the idling speed components;
               The speed recommended by the manufacturer, plus 250 revolutions per minute;
               The cut-in speed of automatic clutches.
              2.5.2.6. In addition, settings incompatible with correct running of the engine shall not be adopted as measurement settings. In particular, when the engine is equipped with several carburettors all the carburettors shall have the same setting.
              2.6. Additional requirements for