[s-cars] Violent Deceleration Under WOT

[Tom Green]

Tim,

Bookmark SJM's site as it contains a wealth of information on this and
other maladies common to the 20V turbo.  The engine codes may also
help in diagnosis although this problem usually throws so many codes it
may be confusing.  Don't forget to clear them.
You may have elicited a chuckle from several listers who have  
experienced
the same violent reaction of the car to what is simply the MM hose  
blown off
one end due to a loose clamp or slippery Samco hose.
There are probably not many chuckles from the copilot seat , if  
occupied,
especially if you and wife are dressed and on the way to dinner.  You  
may
not chuckle much if it is a hidden split as Dave Forgie suggests,  
since it may
be in the turbo to crossover hose and more difficult to access.
Whatever the solution, you will be quick to diagnose the problem if  
it occurs
again.
If you have a warm garage, good lighting, and a little time to get  
dirty, I am
confident you will fix things in short order.
On the bright side, someone has Samco sets for sale on Audifans at a  
good
price and immediately available.

Tom '95 S6
          '95 S6 Avant


Tim Larson complains:

After turning turning into the next lane today and pressing about three
quarters of the way down on the throttle in third gear around 35 mph, I
accelerated briefly til maybe 45 when the car experienced what felt like
engine miss but much worse.  Then, just a few seconds later I  
accelerated
hard from a full stop in 1st and at about 4k rpms the car felt like  
it hit a
brick wall, snapped my neck forward, really nasty and  
unpleasantlike.  It
actually felt like instantaneous full brakes.  There was no squel of the
tires as if they had locked up either.  Tried it again after shutting  
the
car off for a bit and it didn't happen anymore.  Just wondering if  
anyone
else has experienced anything else like this.  Seems like something I  
should
worry about, because I don't want to lay off that wonderful throttle.
Thanks much,
Tim
'92 S4

Dave Forgie suggests:

>
> Tim:  It may well be the MAF but I believe you have described the
> symptoms of a split "michelin man" cross-over to intercooler hose.   
> The
> split will be in a valley of the corrugations (due to an  
> accumulation of
> oil and rotting of the rubber).  Under low boost pressures, the split
> does not open up. However, as you push the throttle down, the split
> opens up and releases all the boost, severely slowing the acceleration
> of the car.
>
> You need to remove the belly pan and the remove and inspect the MM
> hose.  Bend it a bit until you can see the splits.  I am quite sure  
> you
> will find them.
>
> If not, try the MAF connections as suggested.