This is an extremely easy thing to check, so everyone with a boost problem should check it, and if you do have the same problem, let me know. Anyways, with the turbo's heatshield off, look at where the wastegate arm is, if you can see a ridg just above the housing, your wastegate is misaligned. see, very simple check. See pics below to know what to look for. And the fix, almost as easy, just hammer the hell out of it until that ridge is no longer visible, just don't get too carried away
Also be careful not to accidentally hit the arm itself and bend it, just hit it square on the weld point where it goes into the turbo.Here is a nice description burchs1 had (he had the same problem)
OK, well my car drives better than it ever has. The problem was caused by a misaligned wastegate. You may have remembered AnthonyR posted a thread here showing picutres of how his wastegate was misaligned, the gate itself was moved up a bit so it did not seal. I suspected this might be the case with my setup so I called Anthony and he came over here tonight. I will be posting some pictures, etc. and we will pin something here, with Rich's approval of course...so you're probably wondering what was done:
1) When looking at the Turbo with the heat shield off you will notice on the exhaust side of turbine is the waste gate arm that attaches to the compressor cbv valve via the actuator push rod.
2) The arm itself sits on a pin attached to the gate arm.
3) If you looked at my gate arm you would see that there was a gap between the gate arm and the turbine housing. Anthony had this same gap, the gap was causing the the internal gate to sit up to high, thus not making a seal at rest.
4) At rest or with the cbv not in bypass mode the hole in the push rod should basically drop right over the pin connected to the gate arm..this was not the case..I had to pull the rod from the compressor side with quite a bit of force to seat the rod on the gate arm.
5) Using several hammers, etc. we hammered down the gate arm on the outside of the turbine housing to eliminate the visible gap...this causes the gate to move down into proper position and gate arm itself moves over slightly such that the push rod aligns properly.
6) Took the car for a drive and man what a difference, car is boosting as it should now! I am very happy.
Now pounding on your turbo with a hammer is something you want to be very careful with, but there is no other way to fix this, as the arm that the push rod attaches to was not positioned properly, shortening or lengthing the rod would have done nothing to fix the vertical alignment of the gate.
here you can see the ridge I'm talking about.
There is where you hit it with the hammer in that little circle as to not bend the arm. Also the orientation of the rod when fully close should be pointing towards the front of the car ever so slightly to the drivers side.
Anyways, holy long post batman, but I was just trying to be thurough
