Hi Group.

I tried this on Rec.Aviation.Ifr, but no one has come up with any good
ideas, so I am bringing it to you guys, (including the ilk).



I had a trip Friday in a 1977 C-337G(pressurized). On the taxi out I
noticed the suction gauge was pegged high. The AI erected ok, but the DG
required many updates on the way to the run-up area. Pulling on to the
runway, we corrected the DG again, by 30 degrees.
We flew VFR to Boise, and checked out the new Garmin 530 just installed.
Once we got on the ground, the avionics guy, we had along, pulled the access
panel in front of the left windshield. On the back of the panel there is a
component that looks like the back of an altimeter, only about half as deep.
It has a tube labeled "Air IN" and this one had no hose attached. Nearby was
a loose hose, which we reconnected. The system worked fine, and we had no
more problems.
Can anyone explain to me how opening a fault anywhere in vacuum system
can deliver a high vacuum? The gauge worked normally, low before start,
rising when the engine lit off. Two source indicators both showed a working
pump on each engine. I assume the component I was looking at was a
regulator, but I fail to see how the fault we found, could give us the
indication we saw.

Al G (There is another Al on the goup now )