[R0]

well,it's because you dont define the engine as turned on after turning it on,and you must add [vehicle] to engine,code should be: and do the same for the other code

pawn Код:

CMD:engine(playerid, params[])
{
    if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
    {
        new vehicle = GetPlayerVehicleID(playerid);
        new engine,lights,alarm,doors,bonnet,boot,objective;
        GetVehicleParamsEx(vehicle,engine,lights,alarm,doors,bonnet,boot,objective);
        if(engine[vehicle] == 0)
        {
            SetVehicleParamsEx(vehicle,1,1,alarm,doors,bonnet,boot,objective);
            new string[256], name[MAX_PLAYER_NAME+1];
            GetPlayerName(playerid, name, sizeof(name));
            format(string, sizeof(string), "* %s turn the ignition and turns off the engine", name);
            SendNearbyMessage(playerid, 15, string, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE);
            engine[vehicle] = 1;
        }
        else
        {
            SetVehicleParamsEx(vehicle,0,0,alarm,doors,bonnet,boot,objective);
            new string[256], name[MAX_PLAYER_NAME+1];
            GetPlayerName(playerid, name, sizeof(name));
            format(string, sizeof(string), "* %s turn the ignition and starts the engine", name);
            SendNearbyMessage(playerid, 15, string, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE, COLOR_PURPLE);
            engine[vehicle] = 0;
        }
    }
    return 1;
}