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Possible Vacume Leak

Discussion in 'A3/S3 Forum (8L Chassis)' started by bree9482, Jul 16, 2013.

  1. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    Hi guys, had my 2002 a3 1.8t aum for a couple of months now. Its had a few problems that l have been trying to work through when l have cash. So far i have replaced the MAF with a bosch one, cleaned the throttle body, injector cleaner twice, had 1 coil pack replaced.

    The problem is the CEL came back on after having it switched off at the weekend. The error codes were a prob with the MAF and system too lean on bank 1. The garage said to run it for a couple of days as l had not had it on a diagnostic machine since replacing the MAF.

    I have called this morning and im booked in for thursday, but cash is not growing on that tree out back anymore lol. Im starting to lean toward a vacume leak ?? I have been reading some threads and people are saying to spray easy start fluid on the pipework. Is this advisable and stupid question but what hoses ??

    The car at idle hunts a little and when holding at around 2500 rpm the revs will suddenly drop with me applying the same amout of throttle.

    Sorry if this is confusing, l would just like to fault find myself to save some cash.

    Thanks for taking the time too read and reply if you have !!

    Brendan
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  3. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 16, 2013]
    smoke test will reveal all. Could be a vacuum or PCV system leak as you describe it. It could even be a faulty 02 sensor thinking it's lean..
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  4. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    Hi Byzan, yeah was thinking 02 sensoor also. I had almost convinced myself but then if the 02 sensor was bad enough to switch on the CEL would it not be down on power and also fuel economy would suffer ???

    right now it still feels like its pulling strong with maybey a slight hesitation lower i the rev range and also mpg is 28+

    cheers
    Brendan
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jul 16, 2013]
    Smoke test FTW....

    Sounds like a vac leak but would have to be a massive one for the 'too lean' fault to trigger... the ECU can adapt up to +/-25% fuelling before the CEL goes on... I'd check all the pipes under the inlet manifold as a start

    <tuffty/>
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  6. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    Thanks tufty !! Im gonna buy the easy start and give the hoses a spray as l have tried all the garges here and could not find 1 that does smoke tests. When i had the throttle body off l just left the original gasket on as it look in good shape, maybe the gasket ???
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  7. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jul 16, 2013]
    Where abouts are you based?

    <tuffty/>
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jul 16, 2013]
    No matter... seen your other thread :)

    <tuffty/>
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  9. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    Glasgow tuffty.
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  10. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    car engine with text.jpg car engine 1 with text.jpg

    I bought easy start spray and sprayed all the vacuum hoses. When l sprayed these pipes in the pics the car would rev a little higher. So hopefully i have found my leak !!

    Now to the changing of said hoses. Does anyone have experience changing these ?? Is it something that should onl be done by a garage?? Do you think this leak is the cause of my problems ??

    Cheers guys for the help !!
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  11. s3dave
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    s3dave TFSI Hybrid

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    [Jul 16, 2013]
    It needs all ripping out, it is the secondary air system that is heavy and troublesome
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  12. bree9482
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    bree9482 Member

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    [Jul 16, 2013]
    Hi dave, what do you mean mate ?? Sorry i am not a mechanic, l just dont mind trying things out unless its defo a garage job !!

    What is the secondary air system ?? what do you mean heavy ??

    It looks wet because l had just sprayed it with the easy start !!

    Are these hoses expensive and could a novice do it ??

    Thanks buddy !!
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