[THE_KNOWN]

if you have a speedo, put

pawn Code:

public OnVehicleDamageStatusUpdate(vehicleid, playerid)
{
new panels, tires;
    GetVehicleDamageStatus(vehicleid, panels, doors, lights, tires);
    bonnet = doors & 0x7;
    if(bonnet == 3)
    {
          SetVehicleParamsEx(vehicleid,VEHICLE_PARAMS_OFF,lights,alarm,doors,bonnet,boot,objective);
}
return 1;
}

will stop engine when bonnet comes off. modify it check its health. if its lower than 500 turn it off.