[mark houghton]

Originally Posted by jwasbury

Mark,

In my own testing, I found that the WUR responds only to boost pressure by lowering control pressure. It does not raise control pressure under vacuum. I believe others here (Alan L comes to mind) have had the same result.

Thanks. I was just operating on logic only - assuming the internal diaphram would move in both directions respective to boost or vacuum. To test it, I sensuously applied my lips to the hose barb, gently blowing and sucking like a street walker, and could hear the diaphram moving in both directions.
I'll just add this little tidbit to my memory banks.