Have just changed the Turbo on my 2009 A4 Convertible did oil flush and changed started the car ran for 3-4 mins no issue then just stopped just like a seized engine just after engine started with a jump, turned engine off come to restart and it wont turn on starter or if does very tightly. New battery fitted.

Second part of question if engine gone what is the difference between the BPW engine and the other 2.0 TDi can you use a different bare engine and swap parts across.