Turbo waste gate - bad?

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

Just got the news from the dealer in Seattle (University) that they believe my 
turbo waste gate is bad. $800 + labor + tax or ~ $950 to replace. and thats a 
deal!!
Here's the scenario: 91 200q20v with 1.3 bar boost max. All hoses ok - dealer 
ran a pressure check and no leaks. Then they blocked off the waste gate and  
presto - lotsa boost. So they think it is the waste gate. Talked with Dobie at 
Turbo Power near Sacramento (recommended by Carlsen). He is not convinced it 
is the waste gate. Everyone says they are very rare to fail. He says that he 
can rebuild one for under $300 *if* that is the problem. Any one have any 
ideas? I would like to try a new ECU just to see what happens (obviously not 
an option with the dealer). Aren't there like about a half dozen different 
things that could prevent max boost, like engine temp, the boost sensor 
itself, etc?? I plan on removing the waste gate tomorrow to see if the valve 
is leaking. I am told that if the diaphragm is torn that I will probably not 
see any positive boost at all so this is not  high on the suspect list.
Anyone want to comment on the possiblility that with having the after run 
coolant sw inop, that the extra heat build up might have warped the valve in 
the waste gate?

TIA,
mike miller
91 200q20v