Re: High Altitude???

["Scott Mo." <scottmo@teleport.com>]

Powells@ezlink.com wrote:
> 
> Friends, since I arrived in Fort Collins, CO (just north of denver) I
> have noticed that the boost in our 1990 200 rarely goes above an
> indicated 1.1 bar.  On occasion I can get the normal 1.3 to 1.4 bar,
> but not dependably.

Well, the 1990 10V Audi Turbos with the Mac14 ECU don't use an altitude
sensor (baro sensor) like the later 1991 200TQ 20V Motronic system so,
the high altitude boost is not limited. 

I wish it used the baro sensor, as at high altitude it would be nice to
limit the boost on the stock K24 turbo, I would not recommend going over
1.7-1.8 bar boost map settings in the ECU. On the way to the Pikes Peak
Audi Fest, in my 89 200TQ, during a brief test at ~3000RPM, WOT,  with
the brakes on to limit engine speed,  I saw ~1.8 bar boost as I passed
through the Eisenhower tunnel at ~10,000 feet elevation. 

I will provide the turbo/intercooler air temperature data from tests
during this Pikes Peak trip in another post. Needless to say, the K24
starts pumping out some really hot air at high altitudes....

As far as your problem goes, you should check for any stored fault
codes, and run the ECU controlled output tests on the solenoids. My web
page has the details on this, Go to

http://www.teleport.com/~scottmo/ecuf.html

Assuming the knock sensor is working ok, the problem could be the WOT
portion of the throttle switch, if you have the original throttle switch
on the car, I would suggest replacing it, they are always intermittent
in operation on the older vehicles. Other possibilities include, the
wiring from the Throttle switch to the ECU, the Waste Gate freq valve
(i.e. solenoid), hose connections to this solenoid, the multi-function
temp sensor could be grounding terminal 2 which will limit the boost and
not allow the A/C compressor to run. My web page has some other things
to check, go to

http://www.teleport.com/~scottmo/boost.html

HTH
-- 
Scott Mockry
http://www.teleport.com/~scottmo/