That brown wire is the low oil pressure sender wire.... (pretty sure)

Check the AFM connection, lately, 1 one of the 4 wires did get squeeze
between the little oval gasket inside the plug... like other did mention,
check everything you had to unplug wile doing the head, Grounds!!!! anything
could make a bad connection... OS, AFM, Temp2, harness, injectors connectors...

Mmm...2...minutes, choke/cold start related... Any smoke in the back before
it stall!!! Fuel pressure/connection ok????

Cheers, Ben
http://www.benplace.com/vw2.htm