200 20V Running issues/ Code

[Ben Swann]

Tony,

There is a plumbing problem with the wastegate and WFGV circuit.  This circuit
works a little different than the earlier 10v design as it regulates pressure
from the bottom of the wastegate only. If there is a leak in one of the lines,
you will either not make regulated boost and/or overboost.  The frequency
valve has connections to a port on the turbo as well as a line to the intake
manifold.  With that are connections to the Bypass valve and finally the
wastegate.  There is an electrical connection to pulse the frequency valve.
Get all this right and I bet you have controlled boost again.

The boost sensor is not likely to be bad, but easily tested with mityvac or
other creative means of providing vacuum and positive pressure with engine off
but ignition on.

Ben

[Date: Tue, 11 Sep 2007 06:41:55 -0500
From: "Tony Hoffman" <auditony at gmail.com>
Subject: 200 20V Running issues/ Code
To: "200q20v at audifans.com" <200q20v at audifans.com>
Message-ID: <7bd5cbf00709110441o46d3c74w785f619cee028c2f at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Ok guys, I've run across a stumper.

I'm working on a friends 200 20V Avant. He bought it with a running problem,
namely whenever on boost it would start to miss/buck. He had a friend of his
pull the line off the wastegate, and it was "good" for
about a month. Now, it runs pretty poorly all the time, to the point of dying
on occasion.

So, I checked the cam timing, spot on. Checked for boost leaks, can't find
any. The code that comes up is 2224. Here is the description, courtesy of SJM
autotechnic:  "Maximum Charge Pressure Exceeded, Intake air leak after
turbocharger, ECU Vacuum/pressure line has leak between intake manifold Waste
gate or pressure hose, Waste Gate Solenoid/hose problem, ECU pressure sensor
malfunction Symptom: Misfire during wide open throttle, boost pressure too
high"

The symptom is exactly what I'm experiencing. I pulled the line going to the
ECU, and I have good vacuum and boost present there. What are the chances of
the internal boost sensor in the ECU going bad? Anybody
have any other ideas?

Stumped in Oklahoma,
Tony Hoffman]