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Boost leak test???????

Discussion in 'A3/S3 Forum (8L Chassis)' started by malcolm30029085, Jan 4, 2010.

  1. malcolm30029085
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    malcolm30029085 Member

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    [Jan 4, 2010]
    just had alot of probs wiyh fuling and power, changed temp sens and thermostat and now car stays at 90 and has alot more power back.. ok so far...
    but under acceleration the car dosnt feel tight like it used to also it dosent pull as much, it also sounds different ( exhaust+_engine)
    i have alll new n75 maf ect... i did a pressure test by putting a air pipe where the maf is and then blocked the pipe that go into the inlet manifold it didnt hold any pressure!!!! is this the right way of doing it?????
    cheers:blahblah1:
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  3. luckymacy
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    luckymacy Member

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    [Jan 4, 2010]
    i have had the same issue and did the same test at the same point because I couldn't find a more convenient place to do the 'tennis ball' test. If you get any further along please take pictures and post! I'd like to figure lack of hard acceleration out too!
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  4. Matt82
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    Matt82 Active Member

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    [Jan 4, 2010]
    pcv venting the "boost" back into the crank?
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  5. MIKE GTR
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    MIKE GTR Member

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    [Jan 4, 2010]
    Go to a decent garage who have a leak testing kit (smoke) and they will tell u straight away - If you're local to chelmsford in essex try Shephard Motors on 01245 477 999 ask for dean, if you're not then good luck anyway
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  6. Welly
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    Welly VX220 SC Driver :)

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    [Jan 4, 2010]
    PCV is in the inlet manifold isn't it? If the pipework is blocked off before the inlet mani then I can't see it.

    How much pressure are you applying? If it's all leaking out you should be able to hear it if there is a reasonable amount of pressure.

    Check the intercooler for it's ability to hold pressure, I believe they have a reasonably common issue with losing air.

    Some pics for this would be useful I must admit....
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  7. malcolm30029085
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    malcolm30029085 Member

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    [Jan 4, 2010]
    have tacken it to jabbasport they didnt do a pressuer test tho, where is the pcv on a s3 apy engine and can i test it??
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  8. malcolm30029085
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    malcolm30029085 Member

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    [Jan 4, 2010]
    i put about a bar in there couldnt really pin point where it was coming out although the oil cap was hissing!! i am spikin about 12 psi and holding just under 10 psi on my boost gauge is that right for a standard 210 s3?
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  9. Welly
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    Welly VX220 SC Driver :)

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    [Jan 4, 2010]
    PCV pipe comes out of the underside of the inlet manifold. There are several hoses under there however it's about 6mm and comes out of the bottom of the inlet manifold, has a 90 degree right elbow goes to the right for about 10 inches and then has another 90 degree elbow down into a valve. Hard to explain and I can't find pictures.

    These are common pipes for splitting I agree, but not sure this is your problem. You can test by simply pulling the hose off of the inlet manifold and blocking it up temporarily.

    I'm trying to fathom how exactly you are putting air into the system from the MAF end. Have you removed the pipe from the MAF and are pumping air directly into the turbo intake pipe?

    This test will not show a faulty diverter valve which could be a cause of you power loss issue....
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  10. Welly
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    Welly VX220 SC Driver :)

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    [Jan 4, 2010]
    Have you used VAG COM on the engine management? Not sure what standard boost levels on the APY are, but that doesn't sound much. It's not a great dela more than a normal 1.8T 150 makes!
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  11. Welly
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    Welly VX220 SC Driver :)

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    [Jan 4, 2010]
    Block off the PCV system and re pressure test. Could be the one way valve on the PCV system is FUBAR.
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  12. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jan 4, 2010]
    you cant just blow into the MAF and expect pressure to be held to the throttle body
    first major leak will be the oil breather which goes into the TIP.. you will hear air escaping if applying pressure via a compressor.. do so slowly and from low pressure! 5psi start... leaks will reveal themselves
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  13. malcolm30029085
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    malcolm30029085 Member

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    [Jan 4, 2010]

    where should i put the pressure into?? and where should i block off to test as much of the system as i can???
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  14. MIKE GTR
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    MIKE GTR Member

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    [Jan 4, 2010]
    Smoke test, end of!
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  15. 1animal1
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    1animal1 The Clar!! it mouves!!! VCDS Map User

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    [Jan 4, 2010]
    apparently smoke test isnt as conclusive or as high pressure as other methods...ive heard
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  16. MIKE GTR
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    MIKE GTR Member

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    [Jan 5, 2010]
    Ok but if smoke comes out you've found the leak, if it doesn't then try all of the above things
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  17. 1animal1
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    1animal1 The Clar!! it mouves!!! VCDS Map User

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    [Jan 5, 2010]
    well yeah but the problem with a smoke test i hear is that it doesnt replicate the same psi that your car will hit under boost.....meaning its wont be conclusive.....although open to being proven wrong as only have someones word for it
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  18. MIKE GTR
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    MIKE GTR Member

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    [Jan 6, 2010]
    My point is that its a simple test, if it works then you've saved your self a **** load of time and effort and probably money if you're not doing it yourself.
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  19. 1animal1
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    1animal1 The Clar!! it mouves!!! VCDS Map User

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    [Jan 6, 2010]
    its the same test as pressurising the system...... you will have to block off various areas such as the MAF, oil breather one way valve etc...... whats the point in paying for half a test which entails much the same
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  20. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Jan 6, 2010]
    What is the exact procedure to do both tests and what equipment should be used
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