[Boxstard]

I just did the same job over the past weekend!

I oriented the vacuum chamber up, vacuum line was long enough to the solenoid, and works just fine. In retrospect, downward orientation would make it easier to access the hose clamp through the intake manifold runners to fine-tune the hose angle to the pump, without the little vacuum chamber nipple getting in the way.

In my case, elastomer diaphragms in the change over valve as well as the check valve were gooey and stuck shut, throwing the check engine light every a few days. I have not annoyed with the light for two days, hope it stays this way for months to come!