Vacuum readings
 

Ok, somehow I managed to loose the instructions on the digital tool to measure the vacuum on my engine and must ask this question...

What is the proper way to use the tool, leaving the second port open:
http://986forum.com/forums/uploads02...1508440426.jpg

Or by covering the second port:
http://986forum.com/forums/uploads02...1508440481.jpg

Now, assuming that mi engine is below the 5" of H2O, does this means that my rings are too worn, or it could be that I have a small vacuum leak?

Thank you in advance for your comments!

The second port should be left open.

that is a pretty trick digital gauge.

I have a $20 analog gauge.....is it accurate enough?

How much is the high tech one??

Those ones are resold everywhere, about $35+ from ebay

https://www.ebay.com/itm/2017-LCD-Digital-Manometer-Differential-Air-Pressure-Meter-Gauge-2Psi-13-79Kpa/112313519245

...or a little less all over the chinese sites...

https://www.aliexpress.com/wholesale?catId=15370801&initiative_id=AS_20171019 145012&SearchText=digital+manometer

Thank you! Now, I know how to use this gizmo :p