BearMcPear
Member
Thank you that page is very useful.@BearMcPear now we run into the problems I've mentioned at the beginning: Me explaining technical things in English @audifan has already written about the difference you will notice instantly when looking at the engine. There are a few more, but they are all not so big: AUA has a fuel rail made of metal, the connections at the fuel rail a a little different, the oil separator is a bit different, AUA has no check valve on the camshaft cover.
The BBY is just the newer version of the 1.4 petrol engine (introduced 2003 I think), but the differences are not so big at all. If your BBY breaks down you can replace it with an AUA and the other way round.
HERE you can find most differences with pictures and so on - but this page is in German.
Now I know I have a BBY engine.