JAM Enginering was first formed in 1978 with the partnership of two BMW owners, James A. Miller, PhD., and John A. Moulton. The company became incorporated in 1981. Starting in 1978 JAM has developed and marketed Weber and Holley carburetor conversions for over 30 different models of German and Japanese cars and trucks. Working with the California Air Resource Board, the University of Santa Clara and the Emissions Testing Laboratories of Northern California JAM has also developed 50-state legal carburetor conversions.

In 1987 JAM started development of a diagnostic computer for engine management systems. JAM and Can-Tron Electronics Company formed a separate research and development company called Elexis in 1988. JAM sold its first computer in 1991, and in 1992 JAM bought Elexis. Jim Miller retired in 1993.

JAM has exhibited at trade shows in San Fransisco, Chicago, San Jose and Las Vegas.

JAM has been a member of the BMW Car Club of America since 1979, the Mercedes Benz Club of America since 1984, the Early Ford V-8 Club since 1992, and the Specialty Equipment Market Association since 1983.

In addition to manufacturing its own products, JAM's machine shop and staff have done R&D and manufacturing for other companies as well as the federal government.