View Full Version : boost Leak or not?

04-27-2013, 11:44 AM
Recently I chipped with Apr stage 1 my awm 01 a4 but working on The car yesterday I notice some kind if hissing more like sucking sound from the line coming from the manifold intake to the suction pump. Is this sound normal since it goes to the suction pump. Suction pump was replace with new one from dealer 2 month ago and all of the hoses around there seem OK. Is this how it is sopposed to work?

Note: when I pinch that hose in the pic the sound stops.


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04-27-2013, 03:15 PM
How does the car run? Do you have a boost gauge and if so what is it reading?

04-27-2013, 06:00 PM
No demon i dont have one, im planing too get one when i find it on the classifieds but the car runs good. Stays at 800 rpms but there are sometimes after sitting for a while that when i turn it on the rpms stay at 1200ish for a minute or so and then drop to 800. Sent from my SPH-L710 using Tapatalk 2

04-27-2013, 06:12 PM
Well if you have a boost leak you will not know until your in boost.
When you get a boost gauge you will be able to find out.
A boost leak and a vacuum leak are similar but different.

05-02-2013, 10:53 AM
Thanks for the reply. What are the differences between them. Will a boost leak will cause just power loss and the vacuum will do what?

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05-03-2013, 03:20 AM
if im not mistaken the boost leak with be lack of power and vacuum leak with cause idling problems/driving problems.

05-03-2013, 03:32 AM
Thanks quattroginger that's what I thought too. Just wanted to make sure I wasn't wrong on that theory.

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09-30-2013, 03:15 PM
I think you have more a problem when you don't hear that noise IMO. My car never made any noise with my clogged suction jet pump, but when I replaced it it started making that noise. It's actually from the crank case check valve. If you pinch the "S" hose from the suction jet pump to the PCV check valve that will also stop the noise just like pinching the "L" line does.

If this isn't the case then I guess we both have the same problem. No one responded to me when I asked about this a year ago so I have assumed that it was okay as is.

Your 1200RPM start up idle speed is only on cold starts where the engine runs for 30 seconds in a closed loop mode. It's to heat the O2 sensor up. You probably also hear your Secondary air pump run during this time as well.
A more detailed explanation can be found below

10-02-2013, 07:46 AM
do a boost leak test on the car its not to hard I think there is a diy on here or vwvortex. If I have time ill look it up for you.

edit: I believe this is the DIY (http://forums.vwvortex.com/showthread.php?5149361-DIY-Boost-Leak-Tester) I used, this Tester (http://www.audizine.com/forum/showthread.php/190404-DIY-ALL-1-8T-Boost-Leak-Tester) on my car worked great. well one if the 2.