Theory of Operation and Calibration: D.C. Johnson FAC-1

Here is another D.C. Johnson and Associates Inc. product from 1984, the FAC-1. This is the most prolific device of it’s kind. Originally designed in 1981 by Dave Johnson to retrofit European market version cars built from 1977 to 1986 equipped with a CIS Electro-Mechanical Fuel Injection System known as K-Jetronic. Tens of thousands were manufactured and installed. Many are still in service today.

The D.C. Johnson FAC-1 is an Air/Fuel control unit. It adds the closed loop Oxygen sensor feedback loop to CIS Fuel Injection Systems not originally equipped with this feature. It was designed to retrofit cars built for sale in the European market before emissions regulations were instituted. This add on allowed them to meet United States specifications after they were imported into the United States of America.

ENGINEER”S NOTE: One of my “Hobbies” is upkeep of the legacy of this product line created by my Father, David C. Johnson. These devices were produced from 1981 through 1986. The company that manufactured and marketed them (D.C. Johnson and Associates Inc.) was founded in late 1982 and was closed in August 1986. I created the website in 2008 after an inquiry into the availability of technical information. This led to the realization that there was an ongoing interest in maintaining theses products and the cars on which they are installed.

Vernon Johnson August 5, 2014.

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