i installed a mechanical boost gauge , the vaccuum readsclose to 20 in lower yellow in idle but it doesnt read my boost correct no matter whether i have boost at 7 psi or (rough guess) at 15 it will always read 10 psi i put my gauge on my cousins gsx and it reads perfect , he disconnected the gauge while the car was on and u can clearly here the sucking noise from vacuum hose. when diong the same to my tsi u cant here it but u slightly feel suction at tip of hose , my brother being more mechanically inclined than me noticed that 2 out of 4 nipples on left bottom side of intake manifold did not have hoses or plugs but also did not fell air blowing or any suction from these nipples , does anyone have an idea what might be causing this? my brother believes its either that the clear hose going to gauge might have a crack somewhere (it was mishandle for a while before installation , or he also believes it might be that those nipples on intake manifold may have to be plugged up somehow. the car drives fine no problems , i just want to fix this problem so it doenst lead into long run problems. thank you and i'd appreciate help</P>

 

You're brother is for the most part right. Maybe there is a kink in the vacuum hose or a crack. Also where did you hook up the vacuum line for the boost gauge?

 

it isconnected tothe bottom hose of fuel pressure solinoid . p.s. it is a 1st gen tsi awd , so u can get an idea of the setup. we might really suspect the hose because we re routed the hose to turbo compressor side but it still read wrong .