lda hook up

[desertwilow]

when my 1.9 td came(used) the lda was hooked up to one of the injectors.  not knowing what an lda was or much about turbos the only thing i wondered was why there where two return lines from the injectors going to different places.  anyway there is a nipple on the intake manifold right next to the turbo hose that is not being used.  is this where the lda hooks up?  if not where at and what is the damn nipple for?  also a little oil is leaking from the turbo and if i rub a finger on the inside of the turbo to manifold hose there is a little oil.  how big of a big deal is that?  there is photo of the set up @ http://www.vwdiesel.net/phpBB/viewtopic.php?t=1417&highlight=lda
cheers