[200q20v] boost controllers

C1J1Miller at aol.com C1J1Miller at aol.com
Mon Jul 24 11:34:01 EDT 2000

In a message dated Mon, 24 Jul 2000 10:24:55 AM Eastern Daylight Time, Phil Rose <pjrose at frontiernet.net> writes:

<< At 10:09 AM -0400 7/24/00, Brian.Link at Level3.com wrote:
>Has anyone installed an after market boost controller?  I'm thinking my
>surging at high boost is due too the WGFV.  Any BTDT.
>Brian Link
>Boulder, CO.

What do you mean by "after market boost controller"? The WGFV is easy to
test --measure resistance as per Bentley and also do the "output tests"
(audible or with LED) as described in SJM's web pages. I needed a new WGFV
a few weeks ago--bought the oem valve from Carlsen Audi (Linda) for $55.
That solved the problem, which was not surging, but simply the fact that
the max boost was limited to 1.4 bar.

Surging at steady throttle can be a sign of a dead oxy sensor.

Phil Rose

The wgfv may not work correctly even if in-spec for resistance, although that's a good test for a truly dead one.  A better method of evaluation, IMO, is to use a test light circuit hooked up to monitor when the wgfv is activated by the ECU.

The O2 sensor is not really used at high boost, as it reacts too slowly.  My guess is that it's input is discounted at full throttle, and the ECU intentionally adds excess fuel to keep the system cool.

I believe the after market controllers are the a'pexi or similar, correct?

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