This is somewhat normal. The combination of retarded timing and lean mixture
make for low idle vacuum readings.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Michael Magnani
Sent: Sunday, October 26, 2014 7:59 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Vacuum gauge readings

Hi all,
I just completed an installation of a voltmeter, oil pressure, oil
temperature and a vacuum gauge in my stock, 1990, 2.1 WBX with 105,000
miles. No leaks, no smoke. Everything nice and as it should be - except for
the vacuum gauge. At idle, instead of reading the expected 20 In. Hg, it
reads about 13. When I rev it up and then let go of the throttle, the needle
will get to 20, but then go down into the 13-15 In. Hg. range.  I've got the
1/8" vacuum tube Teed into the hose between the Air Plenum and the Fuel
Pressure Regulator. I've tried two different vacuum gauges to verify that
the dashboard gauge is reading properly.
I've verified the ignition timing at 35 degrees BTDC @ 3000 RPM with the
temp sensors connected. The engine runs perfectly and makes as much power as
it ever did. I'm confused. Can anyone offer any help?
Thanks,
Mike M

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