In this article we will talk about tuning ECUs Motronic (Bosch), GM, DSM (Mitsubishi), Jetronic, etc.: BMW, Audi, Volkswagen, Volvo, Chevrolet and not only, with external EPROM memory: 27c128, 27c256, 27c512, 27f512, etc. This is a relatively outdated ECU cars 80-90-ies. Many tuners will say that the ECU data is not "chipable” or setting up ECU data is very difficult, and the best solution is to install a "sports" control unit such as MegaSquirt, Vems, AEM, Haltech, etc., but due to the hardware primitiveness, fortunately, there are currently ways for these cars to fully configure online. For this purpose, there are memory emulators that allow you to detect the memory chip with the ability to change the memory dump (ECU firmware) in real time using special software for editing calibrations. The advantages of setting up a standard control unit, as opposed to installing an external one, are: maintaining a standard diagnostic system; no need to replace or rework standard wiring; no need to replace or supplement sensors; no need to coordinate on-board control units with the engine ECU.