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RE: extreme lack of oomph in 5kCST

From: 	owner-quattro@coimbra.ans.net on behalf of Brett Dikeman
Sent: 	Monday, August 11, 1997 10:29 PM
To: 	quattro@coimbra.ans.net
Subject: 	extreme lack of oomph in 5kCST

OK, big problems...within the past 2 weeks or so, I've been slowly
"loosing" boost pressure...that, and all of the sudden, the car didn't like
to go above about 4000 RPM under what little boost there was...power would
be very, very jerky.
Finally, on my trip to upstate New York, I found it almost impossible to
get ANY boost, and if I did, power again would be very jerky.  I noticed
that pushing the pedal all the way down(ie, full throttle switch), it
aggrivated the problem.
At the end of last week, I was going from NY to NH, noticed the same thing,
only much worse.  Finally, coming home from NH, I was following someone who
knew how to get home, and he decided to pass a gentleman traveling rather
slowly on a small backcountry road.  Well, I go to make the pass, and I'm
about even with the guy when traffic comes around the corner in the other
direction, I'm not making much progress, thinking "aw, #*$!"...then, as if
sensing the urgency, I get pushed into the seat as the car decides to go to
1.1 bar ("wwwwwwwwwhhhhooooaaaaahhhooo......") (whew)
Occasionally, it does this when accelerating into the highway, but again,
this happens very rarely.  Usually, it has to be in 3rd or 4th, going
uphill, with luggage, to barely hit 1.1

Other sympoms from the misbehaving creature:
-balky.  Very balky.  Been finding it very hard to get out of my driveway,
which is a slight hill.  Also, when I'm in 3rd+4th, the car jumps(picture a
new stickshift driver, trying to start up, bucking the car.  Now, picture
this in a car going 40, in 4th, when I let my foot off the gas, into the
idle position or very close to it)

Things that have been checked:
- MAC-11 diagnostic sequence(engine not running, insert fuse in fuel pump
relay, watch blinky light, do again, turns on fuel pump, etc.)  Wastegate
solenoid made clicking/thumping noise about every second or 1/2 second
- idle stabilizing valve(hums with ignition turned on)
-intercooler->throttle body hose, no cracks
-tested decel fuel cutoff switch (raise engine speed to +2000, quickly
close throttle, hose "visibly contracts"...could barely detect it, but
what's "visibly" mean? :\
- MAC-11 fault code dump, engine running(go drive for 5 min, insert fuse,
watch blinky light)...displayed 4444(no faults)
- MAC-11 hose connection(though the fault code dump supposedly covers this,
and the instrument cluster display shows stuff ok)
- visually inspected hoses n'stuff, prodded here, poked there, pulled
this+that, nothing immediately obvious. No big whooshing noises, used a
hose as an cheap stethoscope, couldn't hear anything near turbo,
intercooler, or throttle body.

On a side note, I removed all the spark plugs(KNG's I think)....they had
triple electrodes.  I asked around, and was told that it was "just another
way of makin 'em"...any disadvantages?  They were also severely worn(1.1 mm
instead of .7), so I cleaned them+re-gapped them, took the car for a spin,
no difference.  Going to replace them...should I stick with the KNG
3-electrode, or get the "official" Bosch plugs?(please, don't start a new
thread on just this, or reply to me just about this.  It's not that
important, I just need to know if the 3 electrode design is worse, or the

When my father called the mechanic on a trip to the nearest payphone during
vacation, the mechanic said his guesses were:
-vacuum leak "somewhere" (really helpful, huh!)
-some sort of fault with the wastegate control
-blown(or should I say non-blown? :) turbocharger

I sorta doubt the last one, since I can hear it spin down when I shut off
the car faintly, and hear it spin up when the windows are down and I step
on the gas.
I don't really think it's #2, since the ECU didn't report anything, and we
could hear the solenoid clicking/thumping.

I'm leaning between a vacuum leak and a problem with the
multifunction-thermo-time-slices-dices-costs-a-lot switch, since there's an
overheat safety switch in the thing, and it causes the ECU to "calm down"
from what I can see.  I'm also suspicious since it was just replaced
because the temperature gauge wasn't working correctly.

Any ideas? Winner gets a free busted thermo-time-slices-dices switch from
the last time it was replaced...two if it's the new MFTTSDCAL switch :)

Oh, brain fart.  Car is 5kCST, 1987.  130k-ish miles.

Thanks in advance to everyone for any info,


Brett Dikeman
dikemanb@edison.ma.ultranet.com	dikemanb@stu.beloit.edu
Hostes alienigeni me abduxerunt.  Qui annus est?
Te audire non possum.  Musa sapientum fixa est in aure.
Fellow Audi fanatic,
	when you did your diagnostic sequence, did you listen for the buzzing of the 
frequency valve?  If this isn't buzzing it could give you all symptoms you 
discribed btdt.  Read my post (Engine performance helpful tip).  Or try going 
through Bentley's OXS Frequency Valve checking procedure section 28.44.  If 
you don't have the Bentley manuals, email me and I can email them to you.  (I 
am assuming your car is 1986-1988)

Audiman1@msn.com (Stefan Bendevis)
1987 5000 CD Quattro