Abstract: Apparatus for use in developing and testing a control system for an internal combustion automobile engine. A housing is located in the automobile where it can be visually observed by an operator of the automobile. Electrical circuitry is installed in the housing. A wiring harness interconnects sensors and electromechanical devices with the circuitry. A programmable memory has a plurality of addresses which are selectably accessible, different addresses in the memory containing information relating to different aspects of the system. Information stored in a selected memory address is changeable thereby changing the operating characteristics of the system. The contents stored in a selected address are visually displayed so an operator can visually verify the information stored therein. Operation of the system while the engine is running is visually monitored to determine system performance during road tests, performance of the system thus being observable under actual driving conditions.