Sounds to me like you're in limp mode. Limp mode will limit the boost to 5psi.

Have you scanned for codes yet?

Couldn't tell you what that bolt is or whats around it, but I wouldn't be too concerned with it personally.

We'll see what others have to say.

 

History: Prior to me buying this 1999 audi A4 1.8TQ in June, the last owner replaced the stock turbo with a K04 after the original blew. The car currently has an APR tune on it and should be from what I understand peaking boost around 14.5 - 17 lbs. Well long story short it's only peaking at 4 - 5 lbs. right now and I'm assuming it has a pretty significant boost leak. I noticed this bolt in the turbo and it has some crystalized...stuff around it, any idea what it could be and what this orifice in the turbo is for?





Also if anyones got an extra one of these hoses let me know, I need one! Mine is getting a nice slice forming on it from the fan housing that is about halfway through the hose now.

 

Whoa, how did my post become the first post? Lol.

 

I have no idea...weird....


Anyways yes I've scanned for codes and cleared them but only with a generic scan tool not a vag-com, would that make a difference?

Any more input would be greatly appreciated.

 

Did you write down the codes? It shouldn't matter if you used a generic cable.

Did you do any modifications before you saw the decrease in boost?

If the opening in that hose is large enough I could see it being the cause of your problems. That is the hose that goes from the turbo inlet to DV correct?

The fact that you're running at 5psi though is still making me think you're in limp mode.

 

I did write the codes down, I'll see if I can find the piece of paper in my car.

At the time the car starting boosting at 5lbs I was switching out an MBC that was on it with a better one. This isn't the first MBC I've installed and I was going through the boost adjustment procedures properly. The reason I was even switching out the MBC was because the car was boosting at 11 lbs prior to that and frankly felt slower than that! I hope I'm only in limp mode and ya it's the inlet to DV hose.