I was searching this site for flooded engine, and found this video that help fix the problem.
2002 x5 e53 225,000 miles. It was cold, 10 degrees F, and being an older car I wanted to keep it in the garage. I started the car on the first crank and moved the car inside and turned off engine. Car was on no more than 1 min. Next morning I tried to start the car and It just kept cranking but not starting.
After watching this video, I now know I had to keep my foot on the pedal.
https://www.youtube.com/watch?v=4Ha9Gq72wNs
bobbio