Re: wastgate control valve operation - is alldata wrong?

[Scott Mockry <scottmo@teleport.com>]

Dave,

It looks like the All-Data info is backwards, with the WG solenoid turned
off or disconnected, you should be able to blow through the hose from the
turbo intake, through the valve, and out the hose that connects to the top
of the waste gate. When the solenoid is energized, it connects the port
from the intake manifold (boost/Vacuum) to the top of the waste gate
diaphragm. 

It was set up that way, so if the wiring or the solenoid fails, you won't
get an overboost condition.

I would not recommend connecting +12V directly to the WG solenoid for very
long (>1 sec) as you can let the smoke out of this solenoid valve :-(

You may have already seen this, but if not:
The best way to test the WG solenoid is to run the ECU output tests which
will safely toggle the WG solenoid on and off. You can blow through the
hoses while running this test. The details are at

http://www.teleport.com/~scottmo/ecuf.html

One other good test is to have the engine idling, disconnect the throttle
switch connector and jumper across the two lower pins (WOT connector pins),
the WG solenoid should then be switched on and off "briefly' after
connecting the jumper. This ensures the Multi-function switch is not
defective and signaling an overheat condition which will limit boost. You
can connect up a vacuum gauge to the hose from the solenoid to the WG top
(disconnect the hose from the top of the WG) to watch the gauge needle
swing back and forth as the waste gate solenoid is turned on and off.

Details on this test can be found at
http://www.sjmautotechnik.com/10vwaste.html#wgcnt

HTH
Scott Mockry

At 10:28 AM 5/26/99 -0700, Dave Michael wrote:
>specified in the alldata CD:
>
>            With ignition turned off, disconnect vacuum hose between valve
>and intake side of the turbocharger,
>            at the turbo [ I assume they mean wastgate here].
>
>            Blow into  hose
>            - No air should pass through valve
>
>           Briefly energize valve by applying battery power to one terminal
>while grounding the other, while blowing through the 
>           disconnected vacuum line
>            - air should pass through the valve when energize
>
>Well, on mine, I can blow air through when its NOT energized. It blows
>through to the other nipple on the "top" of the valve.
>
>But base on how I understand the valve works, I SHOULD be able to blow
>through the valve:  I thought the valve is supposed to allow either pressure
>or vacuum to the wastegate diaphragm, depending on what the  controller is
>asking the wastegate valve to do. The other top nipple is connected to a
>vacuum source upstream of the turbo intake. All of this is explained very
>well in Scott Mockrey's excellent web sight.
>
>Am I missing something, or is the alldata cd wrong?         
>
>thanks for any help
>
>Dave
>
>1990 200 qw 153,000