Resolved, after 8 weeks...No Start '94 100S

[Cwalln at aol.com]

Well, the culprit was finally found by Carlsen Audi of Palo Alto...a bad 
ignition switch.  

Several people on this list were right, it is probably something obvious and 
relatively simple...I am glad when the recommendation was made not to pull 
the ECU and have another shop step in.

I had to wait nearly a month for my car to reach to top of the list, but 
Carlsen ultimately found the problem.

Thanks again!

Chris W.

FYI  My original email to quatro at audifans.com is attached at the bottom.  I 
received numerous and excellent suggestions from my original question.

Subj:   No Start '94 100S...the common suspects have been eliminated...ideas??
To: quattro at audifans.com

My '94 100S has been perfectly reliable for the 5 years I have owned it.  Two 
weeks ago, it would not start...no problem turning over...a computer 
somewhere appears to be not giving the ok to start...towed the car to a shop 
great in diagnostics.

No error codes.  The shop has been going through and swapping out computer 
parts from a same vintage, but running Audi, in an attempt to identify the 
problem.  The common suspects, the crankshaft position sensor and the 
ignition control module appear to be working properly.

Before the shop goes the next step and pulls the main and very expensive ECU 
deeply buried behind the glove box...has anyone out there seen this kind of 
problem, or have some ideas on how to find the culprit?

Even the Audi technician at the local dealer is stumped.

Chris W.