Re: MB engine overboost.

[Robert Houk - SMCC WorkGroup Server Firmware <Robert.Houk@East.Sun.COM>]

   > Some "real numbers" would be good to see (actual manifold pressure
   > readings; wastegate control duty cycle values; O2-sensor readings;
   > etc., and so forth)...

   All of these vehicles are stock (or, in John Robinson's case, it was when he 
   had the problem).  The problem is that it is extremely intermittent.  John saw 
   the problem only twice - it's only once happened (to our knowledge) to a 
   professional mechanic.  On my car, I used to see it during the warm-up phase 
   once or twice a week - but it never happened with the instruments attached.

Ah yes, the most fun kind of problem, the intermittent one!

Are all of the problems in the warm-up period? (I still suspect the
ECU; but I can't imagine it disabling the boost check when cold; if
anything it should run *underboosted* when cold)

Experiment: What is the "failure" mode of disconnecting [unplugging
the wires to] the WGFV -- does the boost run uncontrolled (overboost),
or do you get minimal boost? If the disconnect behaviour is to run
overboost, then this nicely tallies with the observation that the
problem tends to go away when you start poking and proding, looking
for it -- flaky connector in the cable makes erratic contact. Very
typical Audi!

I fully sympathize with how many weeks it can take to finally capture
an instrumented sample of an intermittent problem ("fond" memories of
weeks driving around with the passenger seat full of meters alligator-
clipped into the dashboard...).

					-RDH