This paper reports the results of studying the electronic control system designed for a gas internal combustion engine with spark ignition operated on liquefied petroleum gas. A new feature in the control system is the possibility to provide the most effective sequential type of gas fuel injection, in which fuel is injected in a sequence corresponding to the order of operation of the cylinders. The special feature of the designed control system is that a movable voltage distributor (ignition distributor) of the ignition system was modified to ensure sequential injection. The ignition distributor modification involves installing an additional setting disc with one integrated permanent magnet on its drive shaft and an additional Hall sensor on the body of the ignition distributor. This makes it possible to ensure that the electronic control unit receives a signal about the angular position of the camshaft, thereby enabling consistent fuel injection. The principle of operation of the gas engine control system provided by the electronic control unit has been described. The structure of the modified ignition distributor is shown. Tests of the gas engine with a new control system involving the designed electronic control unit Avenir Gaz 37 "B" and the software module "B2" were carried out. The tests confirmed the feasibility of the designed electronic control system, which implies consistent injection of gas fuel. In addition, idling tests have shown that the carbon monoxide and hydrocarbon content in exhaust engine gases is significantly lower than the maximum allowable for motors without catalysts. The control system designed could be used for converting the diesel vehicles in operation into gas engines. The use of this control system ensures their safe operation.