vacum reading question

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Apr 25, 2015 | 04:05 PM

mlm0

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Drifting

Joined: Dec 2012

Posts: 1,504

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From: Georgetown TX

vacum reading question

Getting more confident to work on my engine as time goes on. I would like to check my vacum reading at idle. Where is best place to connect gauge and what reading should I get? Should it hold steady and should it increase as I increase rpm... Not sure how all this vacum stuff works, but thanks to this forum, I am learning much. Mine is 1989 auto, with 49000 miles.

Apr 25, 2015 | 04:21 PM

BOOT77

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Joined: Nov 2010

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From: Michigan

I install a T usually for vac readings, on my 86 I put the T in the line for the fuel regulator. Get several feet of cheap line form a hardware store and you can see the gauge while you drive.

edit: of course I cap it off when not using the gauge

Apr 25, 2015 | 04:21 PM

DanielRicany

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Joined: Jun 2013

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A vacuum gauge can tell you a lot. It comes down to the amount of vacuum that is being drawn in, which is not dependent on RPM.

Best place to connect it is to the HVAC port on the intake.

Here are a few examples of some things you might see. http://youtu.be/NrnzD7PgoHI

Apr 25, 2015 | 07:05 PM

whalepirot

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Joined: Jan 2008

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From: AZ

Quote:

Originally Posted by DanielRicany

A vacuum gauge can tell you a lot.

Plus, it is an oft overlooked troubleshooting tool for a number of engine ailments.

The 'T' in the FPR line is great, being easily accessed and raw, full vacuum.

Apr 25, 2015 | 10:19 PM

Cliff Harris

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Joined: Apr 2002

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From: Anaheim CA

My choice would be the vacuum port on the rear passenger side of the plenum which usually goes to the HVAC system and cruise control. You don't need those while troubleshooting and using this port doesn't require any Ts or similar adapters.