Checking C O And Hc Concentration In The Exhaust - Fiat Bravo Service Manual

Engine
Fuel system
10.

Checking C O and HC concentration in the exhaust

The concentration of carbon monoxide (CO) and unburnt hydrocarbons (HC) in the exhaust is mea-
sured by inserting the probe of a suitably calibrated CO tester in the end of the exhaust pipe for at least
30 cm, as s h o w n in the figure.
If the shape of the end of the exhaust pipe will not allow the probe to be inserted fully, add an appropriate
extension tube which seals properly at the join.
1. Check that the CO and HC concentrations during idling are as specified in the table.
2. If the HC value is outside the specified limit, while the measurement upstream of the catalytic con-
verter was correct, the engine parameters should be considered to be correct, and so the cause of the
fault should be sought in reduced efficiency of the catalytic converter.
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Publication no. 506.670/14