Slow Starting,2002 540

My lovely 2002 540 6 speed has taken to occasionally needing about 10 seconds of cranking before it will start. No apparent pattern, about one time in three. The BMW dealer in Greenville S.C replaced a fuel system valve, suspecting bleed off when shut down. No impact. Hints ? Thanks.

what do you mean cranking?

By "cranking", I mean that I turn the key to the start position, and the starter motor kicks in and turns the engine over rapidly(normal fast start turn over speed), but the motor does not fire. Two times in three, it starts with 2 seconds of cranking, but one time in three it turns and turns for about 10 seconds.

You sure your holding the clutch all the way down, and the trans is in neutral? Also, when you try to start the car, whats it sound like, does it sound like the starter is working, but the plugs are getting no spark, or the starter really doesnt work well?

sounds like fuel pressure problem, I would have replaced the fuel pressure regulator, (sounds like the dealer did that). could also be fuel pump, fuel pump relay, ECU, etc.etc. this kind of problem may take a while to find.