[s-cars] Chasing a boost leak -

[Ingo Rautenberg]

My guess is the WGV is probably OK.  Easy test is disconnecting it  
and see.  If it's functioning properly, you should find noticeably  
less boost (like 12-13 lbs IIRC).

What about Leaking BPV?

Ingo

On Apr 15, 2007, at 11:09 AM, Mike Claire wrote:

> re: the WGFV - I ran the Motronic diags described on Scott  
> Mockrey's site, which includes the WGFV.  I'm talking about the  
> test that checks the throttle pot, the injectors, the carbon  
> canister valve, ISV, etc.  The WGFV clicks the same as it always  
> has.  Is that good enough to eliminate it as a suspect?
>
> I have Samcos with breeze clamps.  The entire intake system  
> including PVC system pretty much holds 10 or 15 lbs pressure (using  
> a 3 inch PVC pipe cleanout with a compressor quick connect tapped  
> into it.  It doesn't hold pressure indefinately, it does leak down  
> very slowly.   Mostly through the valve cover oil cap.  I had to  
> push down pretty hard on it to build pressure.
>
> Bob Myers reminded me to check the ECU connection in the cabin -  
> good call because somehow I overlooked it.
>
>
>
> Thanks again guys, I'm out of ideas of my own.
> Mike
>
> On 4/15/07, Ingo Rautenberg <ingo.rautenberg at gmail.com> wrote:
> Faulty WGFV?  Have you actually removed and examined all of the hoses
> for possible tears?  Improperly-torqued-down hose clamps - rips at
> the hose clamps (if oem hoses).  That lower hose at the passenger
> side at the turbo seems to be the culprit more often than not IME.
> One that really threw me off at the track at Road America in 2001:
> boost leak at the aftermarket VDO boost gauge!
>
> Hope you find it sooner rather than later!
>
> Ingo
>
> On Apr 15, 2007, at 2:26 AM, s-car-list-request at audifans.com wrote:
>
> > From: "Mike Claire" <mike.claire at gmail.com>
> > Date: April 15, 2007 2:26:42 AM GMT-04:00
> > To: "S-car list" < s-car-list at audifans.com>
> > Subject: [s-cars] Chasing a boost leak -
> >
> >
> > Gents:  After spending some time in the Home Depot plumbing
> > department, I
> > figured I'd make short work out of my boost woes.  But, no joy.
> >
> > The subject is a '93 with a metal crossover, all-metal intercooler,
> > Samcos,
> > and Pastore 1+ chip.  I'm used to seeing 22 lbs on full boost  
> with my
> > Autometer boost gauge.  Now it reads more like 16 or 17 lbs, and
> > there are
> > some new boost-related noises coming from under the hood.
> >
> > Here's my main question:  If I'm missing 5 or 6 lbs of boost, is
> > that a big
> > enough leak to easily find when I pressurize the plenum with about
> > 10 or 15
> > lbs with my compressor?  Because I'm not hearing it.  I figured a 5
> > lb leak
> > would be easy to hear.
> >
> > Now I'm wondering if it's even a leak at all, or if it's the ECU
> > backing off
> > boost.  I pulled the codes by blinking them out.  Results are
> > inconsistent.
> > I've seen 2212 (throttle potentiometer), and 2111 (RPM sensor),
> > intermittently.  I've had no symptoms of problems with these.  I  
> read
> > everything on Scott Mockrey's site, and ran the Motronic
> > diagnostics (which
> > includes the throttle pot), no problems.
> >
> > I've been chasing this issue for weeks now, and sometimes I see  
> codes,
> > sometimes I get no codes at all.  I'm not convinced the spurious
> > codes are
> > even related to the low boost problem - for all I know the car's  
> been
> > throwing codes a long time.  The car's running well, but not  
> perfect.
> > Occasionally I get slight misfiring under full boost.  I've been
> > suspecting
> > a weak coil - but who knows.    16 lbs boost is way higher than
> > limp home
> > mode, so I don't know - can the ECU even be involved here?
> >
> > One more thing about the codes - I haven't seen any since I
> > replaced the
> > little rubber tee hose that connects the PCV to the underside of
> > the intake
> > - it was split wide open.  (I only picked up a pound or 2 of boost
> > after
> > fixing it.  But the boost needle doesn't flutter anymore).
> >
> > In general, the car pulls strong and smooth, but boost is low.
> >
> > So - boost leak, ECU backing off boost?  Or 3rd option - is a
> > failing turbo
> > a possibility?  There's a weird noise under there between 8 and 10
> > or 11 lbs
> > when under WOT.  I can't even describe it, but I pictured a split  
> hose
> > making that noise.  There are no split hoses.  But the noise is
> > fairly new,
> > and it's only heard at WOT, when boost is building fast.  I hear
> > the turbo
> > whistle just like always.
> >
> >
> >
> > Thanks
> > Mike
>
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