98 audi a4 (b5) no boost at all,dont even hear the hiss
 

any one have any suggestions , i just picked this a4 up it has a 1.8t and feels like no boost at all, i already did a psi check on the air inlet , (thats good) i checked the (dv) thats good too , what gives ? im at a loss here guys,any advise

This is a very broad question, because there are quite a few things that could be going wrong. Let's start from the basics

1. Do you have a boost gauge? If not, get one, because diagnosing a boost issue without a gauge is like playing darts in the dark.

2. Once you check that your boost is not correct, a boost/smoke test would be good

3. Pull the cat off the turbo and look inside to make sure the Wastegate flapper is working properly. I have seen them break off causing VERY limited boost

fixxed the problem , it took about 4 hrs but all is well.... i wound up pulling the turbo and waste gate off the car and discovered the waste gate spring had no tension at all. and the flapper inside the exaust side was pancaked thus not creating a good seal ...so i took an old turbo flapper off of another unit and replaced it with mine( hard to do bein u have to grind the flapper arm off and reweld it back together again)so now i have boost again , now i have a autometer boost guage that i have moulded into the top of my dash via fiberglass so i know how much boost is there...

"PSI check on the inlet": does that mean you checked intake pressure? Where did you splice the pressure/vacuum gauge in?

If it was "good", what psi was it? Because if you did, and see pressure, your turbo itself is working!

If you don't have sufficient pressure: my wastegate flap went out (actually made a rattling noise as an indicator, but could also just be very loose or gone).

Do you have smoke (burnt oil; another indicator of a gone turbo).

But first report your intake pressure (tool from Autozone, or better yet, boost gauge as already suggested; you need it anyway).


If it was NOT good