I just purchased a non-starting 2012 Like 200i and diagnosed the problem to the fuel pump. My pump seems to be actually toast, it doesn't pump any fuel, doesn't make any noise when energized, internal resistance of the pump is 6.8 ohms. Before I install the new pump, a Quantum fuel pump, I'd like to really clean out the tank. Whats the easiest way to do a good tank clean out? Remove the tank and drain fuel from the filler cap? Is there a drain for the tank? I dont see one.