This report describes the results of an EPA program conducted on 48 in-use passenger cars. Each of these vehicles was a 1977 Buick equipped with a 350 CID engine and a four barrel carburetor. Some of these engines were equipped with special carburetors which had lead plugs covering their idle mixture screws to prevent maladjustments. The purpose of this program was to gather information on current vehicles which will allow EPA to project the effectiveness of similar systems after they have been employed on future vehicles. The program included direct mail solicitation, a parking lot survey, and complete FTP testing. This work was conducted in the Detroit area and at EPA's Laboratory in Ann Arbor during the summer of 1980. The results indicate that this technique for sealing the idle mixture screws is an effective method for preventing the adjustment of the idle mixture. Average idle emission test results for the sealed carburetor vehicles were similar to the results for untampered vehicles with conventional carburetors. Average idle emissions from vehicles with broken or missing limiter caps were substantially higher.
An Evaluation of Sealed Idle Mixture Adjustment on 1977 Buicks
1980
22 pages
Report
No indication
English
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