what does this part do? [vac switch valve m103]
 

http://i98.photobucket.com/albums/l2...y/IMG_8973.jpg

what does the vacuum switchover valve do in this picture?

Its connected to the intake manifold and the EZL gizmo (i think thats what its called)

sorry i looked at the vacuum diagram again...u sure that's connected to the EZL? cause there should just be a line coming from near the throttle plate to the EZL; shouldn't have a switchover valve inbetween

Can't tell without tracing the line out, but it could be EGR or similar, purge, etc.... Trace it out....

I stand corrected:

The EZL's vac line goes into the intake manifold closed to itself
The Switch's line goes into the port just to the left of the EZL's in the manifold
The Switch's other line goes behind the headlamp to what appears to be a dashpod or something.

My question is: what does it do? I was attempting to adjust my mixture via duty cycle when I lost all readings after 30 seconds @ idle. I tap the throttle up enough to make that switch click it come back...

check you headlamps to see if they aren't vacuum height adjustable.
Take three or four HIGH res photos from directly above the engine. (in quadrants) we will be able to better see what's going on there..

High Res pictures:

http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8974.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8975.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8976.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8977.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8978.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8979.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8980.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8981.jpg
http://i98.photobucket.com/albums/l250/MafiaNicky/IMG_8982.jpg

This whole thing tracks back to me adjusting the mixture via duty cycle..I was working on it for a good while (long enough to get to op temp) and i was waiting for the 30 seconds to pass so it could go to ECU/EHA/Lambda control and once it did..the scope flatlined...it would come back if i hit the throttle just enough to open up that vac switch..maybe thats just a coincidence..

Good job with the pics, I traced the most visible line that I could see It takes it source from the manifold, and the line that heads towards the headlamp could be a vent line, and the line running from the bottom of that valve would likely be what ever is needing switched vacuum.

hmm,

Do you think is switching to vent excess vacuum?

I dont recall ever hearing this thing switch on/off when i had the 2.6L motor in there...
(not saying that it was operating as it should have been but just an observation)

I doubt that very much. maybe try disconnecting it and see if anything changes? *shrug*