This article presents methods of acquisition of information from vehicle electronic components, with the purpose of its use to control the additional devices. These additional devices can comprise an LPG fitting, which was installed on a tested vehicle. Also, the way of modifying the contents of the engine control unit has been shown in order to examine the influence of the serial settings of the injection timing. Information that can be obtained from the CAN (Controller Area Network) allow for the lack of interference with the original manufacturer wiring, not disturbing the analogue signals at the same time. Modification of controller memory contents enables the improvement of performance parameters, especially in the case of the compression-ignition engine being fuelled with the addition of LPG. In the Summary section, the dynamometer test results of the modified vehicle have been presented. The tests were conducted for different control parameters during powering with Diesel fuel exclusively, as well as with the addition of LPG