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Old 05-17-2013, 10:53 PM
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Mark Hawkins
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Default Vacuum Gauge

Help. Trying to learn how to use a vacuum gauge. I would like to test my hoses for pressure. I have not purchased a gauge as of yet. Any recommendations? I have an '81.
Old 05-17-2013, 11:15 PM
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MakoJoe
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I did this many years ago and Sears still sells this stuff many of them are still on the shelves in the automotive section of the store.

They are very easy to use to look for vacuum leaks in the system main thing is have a manual that tells the pressure each line should have and test it.

I bought lots of tools years ago. Timing Light, Electrical Testing Kit, Vacuum Gauge

http://www.sears.com/search=automoti...&storeId=10153

Search here for tools for things you may think you need.

Main Items are the Vacuum Gauge, Timing Light and Electrical Testing Kit.

http://www.sears.com/kd-tools-fuel-p...2000P?prdNo=14

Last edited by MakoJoe; 05-17-2013 at 11:22 PM.
Old 05-18-2013, 02:42 AM
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hipocars1
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If you want to test vacuum systems on any cars, buy a MityVac hand vacuum pump. The gauge is built into the tool.
http://www.mityvac.com/
Old 05-18-2013, 07:56 AM
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LannyL81
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Ahhhh...a fellow '81 owner:
I assume you are want to check the headlight hoses, is this correct?

Get one of the Mighty Vac style vacuum pumps...either with gauge or without. Remove the vacuum line from the back of the intake manifold, slip one of the adapters that comes with the MightyVac into the end that was on the intake manifold.
Then create a vacuum. If no vacuum can be created and held, then there is a leak....duh.....isolate sections to find the leak using a finger to plug an open hose end.

A vacuum gauge is good to check the vacuum the engine creates and is a good tool for checking the engine for leaking valves, rings, etc.

Good luck and let us know what you find.
Old 05-18-2013, 08:09 AM
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Alan 71
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Hi Mark,
I agree that a MityVac is the tool to buy.
It will come with a little instruction booklet that will explain how to use it and how to test different things with it.
Regards,
Alan
Old 05-18-2013, 12:06 PM
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scottyp99
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Here is a good article on how to use a vacuum gauge for engine diagnostics.

http://www.secondchancegarage.com/public/186.cfm

Scott
Old 05-19-2013, 09:53 PM
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Mark Hawkins
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Originally Posted by MakoJoe
I did this many years ago and Sears still sells this stuff many of them are still on the shelves in the automotive section of the store.

They are very easy to use to look for vacuum leaks in the system main thing is have a manual that tells the pressure each line should have and test it.

I bought lots of tools years ago. Timing Light, Electrical Testing Kit, Vacuum Gauge

http://www.sears.com/search=automoti...&storeId=10153

Search here for tools for things you may think you need.

Main Items are the Vacuum Gauge, Timing Light and Electrical Testing Kit.

http://www.sears.com/kd-tools-fuel-p...2000P?prdNo=14
Thank you for the webpages.
Old 05-19-2013, 09:54 PM
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Mark Hawkins
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Thanks Scotty
Old 05-19-2013, 09:57 PM
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Originally Posted by hipocars1
If you want to test vacuum systems on any cars, buy a MityVac hand vacuum pump. The gauge is built into the tool.
http://www.mityvac.com/


I see that Northern Tool carries the tool. I will check it out. Thanks.
Old 05-19-2013, 09:59 PM
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Google vacuum gauge.. I found this video

Old 05-19-2013, 10:02 PM
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Originally Posted by LannyL81
Ahhhh...a fellow '81 owner:
I assume you are want to check the headlight hoses, is this correct?

Get one of the Mighty Vac style vacuum pumps...either with gauge or without. Remove the vacuum line from the back of the intake manifold, slip one of the adapters that comes with the MightyVac into the end that was on the intake manifold.
Then create a vacuum. If no vacuum can be created and held, then there is a leak....duh.....isolate sections to find the leak using a finger to plug an open hose end.

A vacuum gauge is good to check the vacuum the engine creates and is a good tool for checking the engine for leaking valves, rings, etc.

Good luck and let us know what you find.

LOL. Yes. Left side comes up good, the right one is lazy; last to pop up and the first to go down. There is about a 3 to 4 second delay in the two. I have a new carb, and I still have a little rough idle. I've been running non-ethanel gas and my engine light doesn't come on any more. But I know I need to learn how to use the gauge. Thanks man.
Old 05-19-2013, 10:09 PM
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Vacuum pump or Vacuum gauge ? Vacuum pump is good for diagnosing the actuators/relays/switch/by pass. Wilcox corvette has a great trouble shooting video for the headlight system. A Vacuum gauge is a great tool diagnosing your engines health..

Last edited by Sids04; 05-19-2013 at 10:11 PM.
Old 05-19-2013, 10:09 PM
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Sounds like how my headlights operate...but I know why...the cam I have in the engine.

Prime spots to check for leaks are the headlight switch....as it is the most difficult to get to...and the actuators themselves....witches' hat.

Have fun.
Old 05-19-2013, 10:16 PM
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Mark Hawkins
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Originally Posted by Sids04
Google vacuum gauge.. I found this video

How to Use a Vacuum Gauge for Diagnostics - YouTube
Very interesting. That was rather good! When I was learning to drive back in the early '70's, my dad installed a vacuum guage. When accelerating, i had to keep the needle in the yellow and prefered green areas. That's all I knew about a vacuum guage. We learn something all the time. Thanks.
Old 05-19-2013, 10:19 PM
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Originally Posted by LannyL81
Sounds like how my headlights operate...but I know why...the cam I have in the engine.

Prime spots to check for leaks are the headlight switch....as it is the most difficult to get to...and the actuators themselves....witches' hat.

Have fun.
Headlight switch. Are you talking about where I pull the headlight **** to turn the lights on from within the car? That headlight switch?
Old 05-19-2013, 10:59 PM
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Originally Posted by Mark Hawkins
Headlight switch. Are you talking about where I pull the headlight **** to turn the lights on from within the car? That headlight switch?
yes he is ..

Old 05-19-2013, 11:23 PM
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Originally Posted by Mark Hawkins
Very interesting. That was rather good! When I was learning to drive back in the early '70's, my dad installed a vacuum guage. When accelerating, i had to keep the needle in the yellow and prefered green areas. That's all I knew about a vacuum guage. We learn something all the time. Thanks.
He never explained why? It's an old trick to increase fuel mileage. A vacuum gauge is a good indicator of the load on the engine, so if you keep the vacuum gauge reading on the higher numbers, you won't be pressing so hard on the gas pedal. Also, most carbs have a way of enriching the fuel mixture when vacuum goes below a certain point, again, keep the vacuum high, get better fuel mileage.

So, what is it you are trying to do? Diagnose engine or test headlight system? I use my Mity-Vac for both. here's a great article about how your headlight system works, and how to get it running well, it really helped me a lot:

http://forums.corvetteforum.com/c3-t...tem-works.html

Scott

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