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idea for testing for vaccum leaks

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Old 03-02-12, 10:13 PM
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1 bar boost

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idea for testing for vaccum leaks

so I have been attempting to figure out why my rebuild engine idles so damm high, and I have not explored vaccum leaks enough to rule them out as the main cause.

I was talking with a co-worker he gave me an idea on how to thoroughly test for vacuum leaks. It goes something like this.

Basically what we were talking about was taking a pvc pipe cap the same size diameter of the turbo compressor inlet, drilling a hole in the pipe end which would allow me to fit and seal a air compressor piece (idk the technical name its just the part at the end of the air hose) then I would attach the pvc pipe cap to the air intake on the turbo and use a air compressor and pressurize the intercooler pipe system all the way to the LIM. I plan on using a regulator @ 7-10psi which I assume is about right considering the turbo can boost higher. At this point a leak would be simple to find because the compressed air would hiss as it leaked out or what ever location.

I feel like this may be too simple and Im missing something important/expensive

whats up? anyone done this? thoughts? noble peace prize winner ?
Old 03-02-12, 10:15 PM
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1 bar boost

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going on over two years without a car...

...man it would be hottness to have a driveable FB again
Old 03-02-12, 11:45 PM
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That looks broken

 
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That's pretty much how it's done. These guys sell a decent looking unit that's so cheap it almost doesn't make sense to build one yourself:
http://www.turboboostleaktesters.com/servlet/StoreFront
I blockoff the turbo with a pvc cap and coupler then I stick an air nozzle into a vacuum line. That works ok too. Spray soapy water on anything you suspect is leaking, it will bubble in in the presence of a leak.
Old 03-02-12, 11:46 PM
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check the egr valve
Old 03-03-12, 02:41 AM
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Pressure and soapy water or good old brake clean. Either method works.
Old 03-03-12, 12:14 PM
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I have done this one every car i have every owned. Make your own from a rubber pvc cap at home depot. put a compressor fitting on the end of it and seal it with some sort of sealer so it dosnt leak. spray down the engine with soapy water and watch for bubbles...
Old 03-03-12, 09:57 PM
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Yep. This method works great. I just did this a couple weeks ago. Great way to find leaks.
Old 03-03-12, 10:22 PM
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All you need is a Fogger. You keep the car off. Pressure up the vaccum system with a fogger machine The leaks show themselves, Almost every Mechanic shop has one
Old 03-04-12, 02:49 AM
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a fogger works but you can get a pvc end cap and install a air valve and chuck on the end from lows for cheap
Old 03-04-12, 11:02 PM
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1 bar boost

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great info guys!
Old 03-05-12, 07:23 AM
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Yep. Or if it's running take a can of something flammable like wd-40 or brake clean and spray the suspected area. It will essentially clog the leak for a second the idle will increase again. We did this often on carb boots for motorcycles. But all other methods mentioned here work well too.
Old 03-07-12, 11:52 AM
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Originally Posted by notveryhappyjack
great info guys!
These cars are good cars. They are just picky on settings. and require lots of attention, at least imo. If you are in the seattle area i am Sure their must be a few people i know at least in this Area that are into FB's that know what they are doing
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