Pressurizing system to check for leaks
 

has anyone one ever done this? I'm referring to blocking off the intake etc to test for vacuum leaks in the system. Any good methods?

I thought I remembered reading about people using tennis balls to block off the intakes (granted this was about 5 years or so ago) and then trying to pressurize the system.

ive done it on a DSM with a PVC end cap and a tire pump

single turbo or twin? igo to home depot or lowes i did this and found 3 big leaks changed the whole car. i used an air compressor

From http://www.fd3s.net/boost_problems.html:

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Date: Sat, 5 Sep 1998 12:02:57 -0500
From: "Steve Wynveen"

Per the request of several, I am posting the dimensions for a set of plugs I made up for finding some boost leaks. Please keep in mind that these will not allow you to locate all boost leaks, as some lines only get pressure when a solenoid valve is activated. They will, however, allow you to easily find leaks in gaskets, small cracks or tears in intercooler piping & hoses, and leaking air bypass and charge relief valves.

2 plugs are 2.37" in diameter, with about a 3" dia shoulder. The shoulder isn't necessary, but keeps you from stuffing the plug in so far that you can't get it out. The 2.37" dia section is about 0.80" long. One of the plugs is drilled and tapped for a hose barb with tapered pipe threads. Onto this barb I put a hose attached to a REGULATED source of about 5 psi air pressure. You don't want to put 100 psi into the system or you'll blow the thing apart for sure. These plugs insert into the hoses coming off the airbox, going to the turbos. You should remove the airbox to be able to do this easily.

The next plug is 0.856" diameter, with this section being about 1" long. Make a shoulder if you like. This plug is for the return line from the secondary air switching valve. In hind sight, I don't think this plug is necessary, but I don't know for sure.

If you want to test all the intercooler hoses and pipes, along with the intake manifold & throttle body gaskets, this is all you need. Hook them up and pressurize the system. It may be necessary to turn the motor a few degrees if one of the rotors has happened to stop where the intake and exhaust ports overlap.

If you don't want to pressurize the intake manifold, I also made myself a plug to stick in the hose before the plastic elbow before the throttle body. This plug is 2.734" diameter. If you test with this plug, air will leak out though the PCV system and into the intake manifold. To remedy this, I unscrewed the oil fill cap, and pulled off the PCV. Reach one finger inside & plug off the breather hole and use another finger to block off the nipple the PCV was just on.

I made mine out of plastic (nylon) bar stock at work, and it was a piece of cake. The plastic machines like butter. It allowed me to quickly locate a torn rubber coupler at the top of the y-pipe this past spring. Hope this helps someone out.
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