[s-cars] Boost leak - update, what am I missing here?

[Mike Claire]

You're right, until I prove otherwise it remains a possibility.

Let me pressure test the intake plenum to about 25.  If I don't find a leak,
plugged cats move up the list of suspects.


Mike


On 4/21/07, Theodore Chen <tedebearp at yahoo.com> wrote:
>
> it's still a possibility.  i wonder if you could loosen some bolts
> and allow exhaust to bypass the cats (just temporarily, for testing
> purposes) to see if the boost comes back.
>
> -teddy
>
> --- Mike Claire <mike.claire at gmail.com> wrote:
>
> > Steve Mills suggested clogged cats.  I sure hope not - my Stromung
> cat-back
> > has less than 30K on it, and I keep the car running right.  I doubt I've
> > overheated or otherwise ruined them.
> >
> >
> >
> > Mike
> >
> > On 4/21/07, Steve Mills <s.b.mills at gmail.com> wrote:
> > >
> > > Mike-
> > >
> > >    Could also be clogged cats. When I bought it my 92 wouldn't make
> more
> > > than 1.4 BAR and even getting to that was paiiinnfulllllyyyyy
> > > ssssllloooowwwww. The PO chased what he thought was a boost leak and
> then a
> > > turbo problem for 6-8 months (new turbo, full Samcos, many $$$) and it
> was
> > > just clogged cats the whole time.
> > >
> > >   Cut off everything back of the turbo, install Stromung, whee
> haaaaa!  I
> > > can now peg it at 2.1 (on the factory gauge) at will.
> > >
> > >    HTH-
> > >
> > >    Steve
> > >
> > > On 4/21/07, Mike Claire <mike.claire at gmail.com> wrote:
> > >
> > > > A bunch of you guys replied to me last week with ideas, and I
> appreciate
> > > > the
> > > > help.  I've gone through everything suggested, and have read
> everything
> > > > about these issues I could find on Scott Mockrey's site,and STFA
> with
> > > > abandon.  I'm pretty much tapped - nothing to show for it.  I was
> > > > distracted
> > > > this week by new symptoms - and ultimately #3 coil just failed
> entirely.
> > > > Dead short.  That's fixed now and the car runs great again - except
> it's
> > > >
> > > > still low on boost.
> > > >
> > > > (subject is a '93 S4, MTM 1+ (Pastore) chip.  Used to indicate 22
> lbs on
> > > > A-pillar gauge.  Now it peaks at 16 or 17, and backs down from
> there.)
> > > >
> > > > I'm either losing boost - or not making enough of it.  I don't know
> > > > where
> > > > else to look - what am I missing here?
> > > >
> > > > 1.  Pressure tested main intake plenum to 15 lbs with a compressor
> and
> > > > PVC
> > > > cleanout plugged into the intake boost.  Closed off Samco where it
> > > > enters
> > > > the intake, and the ISV - PASSED
> > > >
> > > > 2.  Pressure tested all the small hoses in the PCV circuit, water
> trap,
> > > > ECU
> > > > connection, boost gauge connection, etc. etc.  PASSED
> > > >
> > > > 3.  Removed BPV, plugged the Samco, plugged vacuum line (eliminate
> > > > possibility of BPV leaking pressure).   PASSED
> > > >
> > > > 4.  Removed silicone line from wastegate, plugged it shut (to test
> for
> > > > possibility of wastegate opening prematurely)  PASSED
> > > >
> > > > I can only think of two possibilities - either the turbo is no
> longer
> > > > capable of building normal boost, or the intake plenum is leaking at
> > > > pressures higher than 15 lbs.
> > > >
> > > > Could the turbo be failing?  It sounds the same and drives the same
> as
> > > > ever
> > > >
> > > >
> > > > I can take the Samco off the turbo outlet and pressure test from
> there,
> > > > but
> > > > I don't have compressor plug handy for that.
> > > >
> > > >
> > > > Before I do that - any ideas?
> > > >
> > > >
> > > > Mike
> > > > _______________________________________________
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> > > >
> > >
> > >
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>
>
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