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Awful, rough start, whats wrong?

Discussion in 'A3/S3 Forum (8L Chassis)' started by J Eyo, Apr 6, 2014.

  1. J Eyo
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    J Eyo Member

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    [Apr 6, 2014]
    Hi guys,

    suffering from a really rough start, what you hear at the beginning is the problem, usually this continues and the car never starts, I have to turn it off and on a couple of times before it will start. Whats causing this? other problems, rough hunting idle, turbo kicks out around 5000rpm and won't start until i turn the car off and on again, down on power, severely drinking fuel, whats wrong?? ideas?
    Last edited by a moderator: Aug 15, 2014
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 6, 2014]
    Any fault codes?

    <tuffty/>
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  4. J Eyo
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    J Eyo Member

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    [Apr 6, 2014]
    Just one: p1297 - pressure loss between turbo and throttle valve
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 6, 2014]
    What are fuel trims looking like? (block 32, VCDS)... particularly long term trims... the code you have is a bit of a bug in the software... VCDS shows this as fault code 17705 (17705/P1297/004759 - Ross-Tech Wiki)... this code is typically thrown when ambient temps are 5 deg or lower and results in loss of power (limp mode)... cycling the ignition resets and all is good again but obviously the code persists...

    The other reason this comes up (the legitimate one) is typically from a vacuum leak... considering the issue you have with the starting then an airleak is favourite... is there anywhere around nera you that can do a smoke test?

    Have you swapped that split-r for a proper DV yet?

    <tuffty/>
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  6. J Eyo
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    J Eyo Member

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    [Apr 6, 2014]
    Switched the stock and forge around, no noticeable difference and exact symptoms persist. Had a pressure test done about 5 months ago and was told the pressure was good :/ i feel like it still could be a leak or my egt is rooted
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  7. J Eyo
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    J Eyo Member

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    [Apr 6, 2014]
    N249 and pcv delete could have thrown the code? Rpm swings wildly without code; the engine is only stable with the code present
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 6, 2014]
    If EGT probe is an issue the a code would be thrown... are you using VCDS or a generic code reader? not all generic code readers read vag specific codes... VAG have extended the OBD P codes to allow for more specific diagnosis

    Shouldn't have affected this at if done correctly... would need to do some logging realistically to see whats going on with the sensor readings... block 032 is a good tell as fuel adaptions will have a high additive value with a vacuum leak on idle...

    <tuffty/>
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  9. J Eyo
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    J Eyo Member

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    [Apr 7, 2014]
    Yeah using full vcds with the Ross tech cable. It's a tricky one, it's booked in tomorrow at a very good diagnostics place, hopefully they'll find something!
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