Oddly enough I have been searching for the last hour on where to hook my vacuum gauge to take readings, and can't find SFA.
It's obvious that you would take a line near the IM, but which line is most common or accurate for readings?

Can I use my OBD scanner to take vacuum readings as well, or is it not accurate?

Thanks

 

what year and engine? do i need to move this for you?

 

1998 Camaro Z28 - LS1.
Wow, I must have been asleep while posting this lol. That would be awesome if you could move this, thanks! Ill be a little more careful in the future..

Just bought a vacuum gauge tester and don't see any good lines to test from.

 

moved it, i would think any vacuum source would work.

 

Anyone?

This would be a helpful thread to others, other than myself as there isn't any information elsewhere I can find.

Might try tapping into the PCV as it seems to be the most accessible.

 

You can use a scan tool to look at the MAP sensor output, assuming the MAP is good. The readings MAP readings will be opposite of what a vacuum gauge will show. The lower the MAP indication the higher the manifold vacuum. Depending on the scan tool and vacuum gauge used you may need to convert KPA to inches of vacuum, etc..
This link will connect to conversion table.
Vacuum Pressure - Converting Units

 

Great, thanks for the tip.

Ill actually compare my OBD readings to the vacuum pressure.
I'm going hook my gauge up to the PCV line and take a reading from there.
This seems to be the most accessible point. I did find a small vacuum leak at the PCV valve, just fixed it with hose clamps. Now to make sure everything else is all good for pressure.