Using the technique of substituting electrical parts which had been in service for those on an essentially new 1958 automobile, the paper shows a substantial radiation in hydrocarbon emissions possible as a result of the maintenance condition of these parts. The wide range of emissions which results from modification of the idle adjustment is also shown. The 1956 CRC Field Survey data are examined on the basis of these findings and the conclusion is reached that the high concentrations reported are probably in the right order of magnitude.
By comparing Field Survey data with those from a regularly maintained Service Fleet it is concluded that substantial reduction in hydrocarbon emissions is possible through regular maintenance. It is also concluded that a fuel saving may accompany this reduction.