vacuum leak or brake booster vacuum leak
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Old December 29th, 2013, 07:35 PM   #1
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vacuum leak or brake booster vacuum leak


Ive had a vaccuum leak for about a year already. I have replaced my intake manifold and gaskets with felpro gaskets and oem ford racing I/m.ive clamped all the hoses running off the cold air intake and the 1 f4om the pcv valve to valve cover. Car idles perfect and runs perfect. The vacuum leak sounds big real loud hissing so I cant understand how I would have no idle issues. Im starting to think it might be a brake booster vacuum leak. I do get a light hissing sound (seperate from initial leak hiss) when I step on the brake pedal. Any ideas?
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Old December 29th, 2013, 07:39 PM   #2
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Our cars use hydoboost not vacuum boost.
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Old December 29th, 2013, 07:45 PM   #3
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Originally Posted by Buddha View Post
Our cars use hydoboost not vacuum boost.
Damn. Im gonna have to read up on how the hydro boost system works.
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Old December 29th, 2013, 07:57 PM   #4
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It takes hydraulic pressure from the power steering pump.
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Old December 29th, 2013, 08:13 PM   #5
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Originally Posted by Buddha View Post
It takes hydraulic pressure from the power steering pump.
I see... so do you have any ideas about where I might want to check for a leak? I don't want to spend 150 $ bucks on a smoke test.
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Old December 29th, 2013, 08:22 PM   #6
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Originally Posted by luv2shuv View Post
I see... so do you have any ideas about where I might want to check for a leak? I don't want to spend 150 $ bucks on a smoke test.
Spray starter fluid around by the lines or back of the motor if there's a leak it will burn the starter fluid you'll hear it


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Old December 29th, 2013, 08:31 PM   #7
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Like stated above, starting fluid around the vacuum leak will affect idle.
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Old December 29th, 2013, 08:47 PM   #8
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Are you using the stock PCV valve or an aftermarket valve


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Old December 29th, 2013, 09:23 PM   #9
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Originally Posted by black02 View Post
Spray starter fluid around by the lines or back of the motor if there's a leak it will burn the starter fluid you'll hear it


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I've done that. I had minor leaks on the hoses that run fron the pcv and the ones that run from the air intake so I clamped them but the leak is still their....

---------- Post added at 06:19 PM ---------- Previous post was at 06:19 PM ----------

Originally Posted by 46L281GT View Post
Are you using the stock PCV valve or an aftermarket valve


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---------- Post added at 06:23 PM ---------- Previous post was at 06:19 PM ----------

Originally Posted by jbodell11 View Post
Like stated above, starting fluid around the vacuum leak will affect idle.
The thing that trips me out is how loud the leak sounds but it doesn't affect the cars idle but the sound goes away then i hit the throttle and the rpms fly up but as soon as its back at idle rpms.... bam the hissing is back... my buddys bmw has a leak that's half as loud and his beemer turns off when its cold at idle.
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Old December 29th, 2013, 10:10 PM   #10
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Oh okay then. The reason I asked is because I had bought a knock-off version and had a strange hissing/rattling sound and it was that crappy valve. I know they are supposed to rattle if you shake them, but this one was audible from within the cabin and definitely outside the vehicle. Just thought it might be the same issue that I had.
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Old December 29th, 2013, 11:20 PM   #11
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Originally Posted by 46L281GT View Post
Oh okay then. The reason I asked is because I had bought a knock-off version and had a strange hissing/rattling sound and it was that crappy valve. I know they are supposed to rattle if you shake them, but this one was audible from within the cabin and definitely outside the vehicle. Just thought it might be the same issue that I had.
A couple months ago I suspected of the pcv valve so I put the old one back on to see if it still hissed... and it did....
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Old December 30th, 2013, 01:18 AM   #12
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Get a vacuum guage and test the vacuum
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