Electronic Fuel Control: Description

The Electronic Fuel Control (EFC) system is used on some 151" 4-cylinder engines built for California (VIN 1). The applicable models include Chevrolet Monza, Oldsmobile Starfire, and Pontiac Sunbird. This system controls emissions through close regulation of air/fuel mixture and use of the Phase II (3-way) catalytic converter.

Major components are the Electronic Control Unit (ECU), oxygen sensor, bimetal input switch, vacuum input switch, vacuum modulator, special 6510C carburetor and the Phase II converter.

NOTE: Some 1979 General Motors models with 151" 4-cylinder and 231" V6 engines for California, including 1980 Skylark, Citation, Omega and Phoenix, use a similar system. Refer to GENERAL MOTORS C-4 SYSTEM in this section.