91 200q owners - low boost

["Mike Miller" <JoMi@msn.com>]

Ok - here's the story on my low boost. (Seeing 1.3 and an occasional 1.4) The 
Seattle dealer (Univ.) said I had a bad wastegate. I was skeptical to say the 
least and didnot relish the thought of replacing a ~$1k part that might not 
solve the problem. I spoke with Ned earlier tonite and he gave me a simple way 
to check out the wastegate  - using a pair of vice grips, clamp off the grey 
hose (bout 1/2 inch diameter) that runs to the wastegate - drive the car and 
if boost increases it is not a wastegate problem - if it doesnot increase, 
then the wastegate is leaking. My test confirmed the wastegate to be leaking. 
Ned also said that at least 3 other 91 200q owners have low boost and have not 
yet solved the problem. At Ned's request, I pulled the waste gate - really an 
easy task. 4 nuts on the wastegate and 3 on the exhaust flange - I also pulled 
a couple others on the metal hose by the  cam cover to get easier access to 
the wastegate bolts. Upon disassembling the wastegate (Ned did not ask me to 
do this!!) I discovered that the valve and valve guide are worn just enough to 
prevent the valve from seating. I checked this by using a shop vac to provide 
air pressure into the exhaust outlet side and putting some kids bubble mix on 
the valve and seat - it was not a big leak, yet must be enough to prevent that 
magical 1.8 bar boost from being reached. I used some 400 grit to remove the 
burrs on the valve stem and lightly hit the valve itself. Upon reassembly, I 
get to 1.3 bar boost easier and hold 1.4 much longer. Obviously, I did not 
cure the problem. If others out there are seeing this problem, then maybe 
there is a design problem with the valve and guide in this model of turbo - I 
have 76k mi and I do not expect a turbo wastegate to go bad in that amount of 
use! I plan on calling AoA on Monday and seeig if I can get any sympathy 
(read: financial help) from them. I suspect I will not have any luck. The 
wastegate looks very simple and it appears any competent machine shop should 
be able to repair the valve, guide and seat. Actually, the seat is probably 
good and just the guide and valve need to be fixed. Anyone that is interested 
in how the saga continues can Email me and I will keep them updated.

mike miller
91 200q