cutout/stumble on an MC engine

[Swann, Benjamin R. (BSWANN)]

Jim,

Keep looking. It could be a torn wastegate diaphragm. A freind of mine
encountered this recently - Same symptoms.  

You can determing by putting correct diameter hose on wastegate bottom hose
and applying suction with mityvac, or just as effective your mouth.  You
should hear the wastgate fall/thunk when vacuem is released.

Ben

[Big thanks to all who replied.  Everyone had the
identical answer.  I'm not sure this is the problem as
the hose SEEMED fine.  Visual and manual inspection
recently.  The dash boost gauge never goes over 1.4
bar.  The cutout is very short.  Definitely less than
1 second.  I have about 3 or 4 wastegates laying
around, but have never opened one.  I will check the
diaphragm on the car and and hose and report.  One
other symptom I noticed is that on a long steep
incline with throttle wide open and 1.4 bar indicated
the car takes forever to accelerate from say 85 to
110.  It just doesn't seem to have any guts.  Could
the weather (95* Fahrenheit and 85% humidity) have
anything to do with this?  Is it possible I'm running
too lean a basic setting?  Maybe time for a cutoff and
plug check?  Again thanks for the responses and I'll
let you all know what I find.]

Jim Accordino
--- Peter Berrevoets <pjberr at home.com> wrote:
> Ah... the dreaded overboost cut-out; sort of like
> hitting a brick wall?
> 
> Check that the big hose to the bottom of the
> wastegate hasn't crumbled with
> age and is leaking, preventing the wastegate from
> functioning properly.
> 
> If that is fine, you may have a tear in the
> wastegate diaphragm, I don't
> know if wastegate frequency valve failure will allow
> for an overboost
> condition as well, but maybe someone else might.
> 
> HTH
> 
> Cheers!
> 
> Peter Berrevoets
> 1990 200TQ
> Toronto, Canada
> http://frontpage.home.net/pjberr/
>