[Lucases]

SA:MP can only detect GTA SA keys like KEY_FIRE or KEY_SPRINT
If you want to use NumPad8 then you should set on of your GTA sa controls to NumPad8.
I will show you how to do that script.
The engine will turn on and off when you press N

PHP код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
        if ((newkeys & KEY_NO) && !(oldkeys & KEY_NO))
        {
                 if(IsPlayerInAnyVehicle(playerid) // checks if the player is in a vehicle
                 {
                         new engine, lights, alarm, doors, bonnet, boot, objective, vehicleid = GetPlayerVehicleID(playerid);
    // we create some variables, these ones will store vehicle data. After we get the id of the vehicle                      
                         GetVehicleParamsEx(vehicleid, engine, lights, alarm, doors, bonnet, boot, objective); //we store vehicles data inside the variables we created
                          if(engine == 0) engine = 1; //if: the engine is off we turn it on
                          else if(engine == 1) engine = 0; // viceversa
                          SetVehicleParamsEx(vehicleid, engine, lights, alarm, doors, bonnet, boot, objective); we update vehicles data
                  }
          }
          return 1;
}