My pump kept on going . Maybe the stock ECU has a 5sec timer but I doubt it. If your car was hard to start why would you want it to cut off. It wont take long to empty it even if you have to turn it on a few times. Its possible the 5sec comes from the fuel pressure reaching its pressure and fuel pressure relay shutting the pump off. With the hose disconnected the pressure wont hit the desired pressure so in theory will keep pumping.