What's This/What's It Do?

Phil Rose pjrose at frontiernet.net
Mon Apr 11 18:25:08 EDT 2005

At 5:54 PM -0400 4/11/05, Kneale Brownson wrote:
>The actual valve is relatively new--installed last fall.  This connection
>is located on a pipe that seems to be metal closer to the turbo and fabric
>covered hose on the other side of where this connection is mounted.

Not sure what you're saying--i.e., what valve was replaced last 
fall--was it the wgfv? In any case, the connector (with arrow) shown 
in your photo is--without any doubt--attached to the wgfv  (aka: 
wastegate frequency valve).


>At 04:20 PM 4/11/2005 -0400, Phil and Judy Rose wrote:
>>At 3:24 PM -0400 4/11/05, Kneale Brownson wrote:
>>>When I had intermittent boost (1.3, 1.4  and then 1.6-1.7 and so on) a
>>>month ago, Ingo suggested the waste gate frequency valve electricals, so I
>>>attempted to take this connector
>  >>http://www.pbase.com/kneale_brownson/image/41941930   apart for cleaning.
>>>Because of the close quarters, I couldn't hold the spring retainer down and
>>>take the connector off.
>>>Anyway, what's the connector indicated by the arrow in the pix do and what
>>>do I probably need to replace?  The fixture onto which the connector goes
>>>looks corroded at least on the outside, and some of the corrosion appears
>>>cracked from my efforts to get the connector off a week ago.
>>   man that's some uuuugly old stuff down there. How old is that car, anyway?
>>That of course, is the wastegate freq. valve connector. The wgfv is a
>>solenoid valve that regulates the amount of boost pressure admitted
>>into the lower chamber of the wastegate ; it has a duty cycle that's
>>determined by a fluctuating voltage that's varied by the ecu
>>according to its boost map . When the valve fails to operate, its
>>default (i.e., no voltage) position is wide open, in which case the
>>wastegate will always see the full boost pressure pushing on it; and
>>therefore it opens prematurely to limit the boost. By "prematurely"
>>is meant there'll be a maximum boost of 1.3 or 1.4 bar rather than
>>the normal 1.8 bar. This low-boost mode of failure is a safety
>>factor. From the looks of your wgfv "relic", I wouldn't be surprised
>>if it needs replacing; however since you report boost is as low as
>>1.0 or 1.1 bar, I suspect that something else-- besides (or in
>>addition to) the wastegate valve--is misbehaving. You could do an
>>audible ("click/clack") test of the  wgfv operation by following the
>>ecu "output tests" procedure described in Bentley or in Scott M's web
>>site.  A silent valve is a sure sign it needs to be replaced. There's
>>also a resistance spec you can check (resistance measured across the
>>two terminals of the valve). But look for other problems: a loose
>>boost hose clamp, etc.
>>*  Phil & Judy Rose           Rochester, NY  *     
>>*        mailto:pjrose at frontiernet.net       *


Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net

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