Originally Posted By: fdcg27
Originally Posted By: oil_film_movies
1979 emissions control systems might have been the worst ever. No microprocessors in GM cars until 1981 did that.
IDK, I remember that the 1975 MY intro of catalytic converters and electronic ignition allowed better tuning with improved drivability, performance and fuel economy as compared to earlier seventies cars.
The 1981 intro of feedback carburetors and a simple microprocessor was mainly to accommodate newly reduced allowable emissions levels for that MY.
GM called this Computer Command Control and it seemed to work pretty well. It was no doubt a cheaper solution than a proper fuel injection system would have been.
Yeah, but the 87 octane unleaded replaced 89 regular leaded which took more timing away. Before electronic computers we had what were essentially analog computers, with tons of vacuum hose, water temp switches, delay valves, calibrated orifices, vacuum signal comparators and amplifiers.
My 82 cadillac cimarron with the "computer command control" had the vacuum to the EGR controlled by both the computer and a water thermoswitch. The computer knew the coolant temp. Explain this redundancy! The speedometer cable went to an intermediate speed sensor "box" then another cable made its way to the speedometer. This was for torque converter clutch control; the Canadians used a mechanical governor.
