This car was handed back to the customer only last week after beeing garaged for almost 3 months , with a switch to turn off crank sensor to allow it to start. As stated it appears to start and run OK after say 20 minutes running when warmed up, with the crank sensor connected.

The garage concerned had run out of time and resources calling in all manner of BMW experts.
Ignition coils replaced, ECU replaced, Crank sensor replaced twice first GSF unit then genuine BMW which was exactly same as original unit, dashboard cluster removed to check if interference to crank , timing checked and re-checked, alternator disconnected to check for noise, wire loom between crank sensor and ECU new section spliced in and a few other things .

Note that both CAM and Crank signals as discussed on my earlier post are present and there appears to be no difference when cold or hot.

Vanos suggested as possible fault but all BMW techies suggest Vanos would not prevent starting.

As one BMW guy said "It just does not like the Crank signal"

Myself and the garage concerned do not like being beaten , however we cannot keep going over old ground .

Any more suggestions as to the cause would be welcome.

Thanks.