So ive been at it again trying to solve my boost leak issue... what i have done, compressed 20 psi air in one turbo inlet, blanked off second turbo, closed off air vent line by left turbo... found few air leaks, but noticed would not hold pressure, found air free flowing from fuel vent line in front of trans..is this normal?? Thoughtit was supposed to hold pressure. getting code P 0117 and Koch P 0118. sometimes boost drops to 4 bar.. any help would be appreciated thanks again

 

You do a pressure test from the top of the turbo inlets? (intake behind MAF)