[s-cars] Chasing a boost leak -

[Ingo Rautenberg]

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