RE: High boost problems on '91 200QW-solved?

["James A. Desveaux" <desveaux@ucla.edu>]

I think I solved the high boost problems with the 200QW.  Thanks to Phil
Rose, Scott Mockrey, Dave Aukerman (sp?), and others for their input.  The
plug wires all looked fine, with no evidence of arcing anywhere.  The
distributor cap and rotor looked fine, and I didn't notice any carbon
tracking.  I did, however, notice some oil in there, but not a lot.  I did
check the small diameter vacuum hoses, the ones that connect at the back of
the intake manifold.  Phil bet me a cup of coffee that the culprit was the
vacuum line to the turbo bypass valve.  I pulled it, blew through it to make
sure it was clear, reattached it to the bypass valve, and then attached my
vacuum pump to make sure it held vacuum.  It did.  So Phil, as a compromise
I'll send you that Starbuck's Frappucino coupon I got in the mail.  I like
mine black and bitter anyway.  I did notice that the middle vacuum hose that
connects at the back of the manifold was iffy, and I cut off the 1/4" or so
at the end that was obviously weak and reconnected it.  This hose goes to a
'T', with one end heading to the ECU, and the other to the fuel pressure
regulator.  The fabric was worn off part of the hose to the fuel pressure
regulator, so I figured I should replace this.  $15. for 2 meters of the
German braided vacuum line.  In the meantime, I tested the wastegate
frequency valve, and it's fine.  After replacing the hoses, I disconnected
the battery to erase the codes, and drove the car up a decent grade in the
Palisades.  This time, the boost gauge quickly shot up to 1.8bar, and then
1.9bar.  I've never seen the gauge go higher than this (it has a mild IA
chip in it), so I guess everything's okay.  Most important, I noticed no
more bucking.  I checked the codes again, and got 4444 this time.  I'm not
positive what fixed the problem, but I suspect it was one of the vacuum lines.

- Jim