2003 X5 4.6is Rumble when starting/ and sometimes a failed start

[KDN32303]

I have a 2003 X5 4.6is with 50k miles... when I start the car and the engine rolls over it also makes a strange rumble sound (rumble may not be the best way to describe it, but it doesnt sound right)... it was enough to worry me so I brought it into the dealer here who could not reproduce the issue so they could not fix it. It also from time to time when turning the key will not roll over.... just make a 'click' sound like the battery is dead... but the electrical components will come on as well as the A/C.... if you turn the key to off then start it again it starts right up...they also had nothing to say about this either. Otherwise the truck runs GREAT, and for an SUV its halls a$$!!

Any Ideas?? Anyone with the same issues?

[autoxerwgn]

Can't help you on the noise but regarding the no crank-no start, but starts on second try. There was a SIB for E39 and E53 cars with the 4.4 M62TU engine up to MY 04 for this issue. The fix was DME software. The 4.6 has almost the same engine and engine management so I would try that first.

[UDM Motorsport]

mine does the same thing, as in when i turn the ignition 'too quick', it clicks/no start, then off and restart and it works.
Normally i wait 2-3 seconds before starting and it works.