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Old 02-18-2013, 11:46 AM   #1
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Gauge Vacuum Test

Anybody tried a gauge vacuum test with good results: steady needle at idle, drop in vacuum once rpm is increased to 2500? If yes, where is the gauge hose supposed to be connected ?

Please advise. Many thx.

Last edited by FutureFast; 02-18-2013 at 11:47 AM.
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Old 02-18-2013, 12:33 PM   #2
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You can read vacuum pressure from the OBD computer using Torque Pro if you have an Android device.
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Old 02-18-2013, 03:00 PM   #3
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May be ... But I was thinking in more of troubleshooting terms. There are various places in the manifolds where I can place the gauge hose, however I am not sure what the correct readings should be. Let's say you have a CCV that doesn't work as it should? How do you troubleshoot that? (I don't believe much in the bag over oil cap "technique" - that can only indicate that you may have a failed or somewhat working CCV). Or, how can you test for the jet sucking pump failure/correct reading? Etc ...

True, at the same time, I don't think anybody ever tried on this forum since I searched and hence the posting.

Thx a whole bunch anyway.
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Old 02-18-2013, 03:41 PM   #4
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A smoke machine is really the best way to test for vacuum leaks. I would say anywhere on the intake tract post throttle body would be acceptable, and you're probably looking for somewhere around 18-20mmHg on the gauge at a hot idle.

There are only two failure modes for the CCV afaik: clogged to the point that it obstructs the vacuum into the crank case (what the "bag over hole" technique is testing for, and broken plastic/loose connections that create a leak.
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