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A4 tfsi idle misfire

Ollie454 Jan 30, 2018

  1. Ollie454

    Ollie454 New Member

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    Really having trouble with my a4 b7 tfsi, I am still getting a misfire only on idle, have changed coilpacks spark plugs, pcv valve and also done a compression test. I am running out of ideas of what it can be only fault code that comes up on scanner was misfire cylinder 3 and I believe it also said fuel lean at low revs, only other thing I could think of is a injector, but want to make sure before I take whole inlet off. Any ideas?
     
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  3. QuattroCalum

    QuattroCalum Well-Known Member saloon Audi A4 Black Edition Saloon Manual

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    Carbon fouling the inlet valves, common problem on tfsi engines it happens because the fuel is directly injected into the cylinder.


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  4. Ollie454

    Ollie454 New Member

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    That would cause a misfire?
     
  5. QuattroCalum

    QuattroCalum Well-Known Member saloon Audi A4 Black Edition Saloon Manual

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    The carbon build up can restrict air flow into the cylinder disrupting fuelling adaptation or even prevent the valve from closing fully.
    https://goo.gl/images/x4pLDF

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  6. Ollie454

    Ollie454 New Member

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    Is there a way to clean without taking the inlet off?
     
  7. QuattroCalum

    QuattroCalum Well-Known Member saloon Audi A4 Black Edition Saloon Manual

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    Not properly no, any fuel additives will never see the inlet manifold or valves. Walnut blasting seems to be popular.


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  8. Ollie454

    Ollie454 New Member

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    If inlet has to come off anyway may as well send injectors off to be tested and cleaned at the same time
     
  9. Oliver Smith

    Oliver Smith New Member

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    Still having problems with the car
     
  10. ch1z64

    ch1z64 C'mon you's bhoy's in Green Team Imola TFSI Owners Group Silver Supporter Team Sprint Audi S3 Manual

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    I recently had the same problem with my S3 tfsi engine and did all you have done but then i bit the bullet and got the walnut clean done and car runs perfectly . Do you get the needle moving slightly when just sitting like as if it was breathing if so then do a vacumm test as you have a slight leak somewhere normally at the pcv maybe a Oring perished on one off the pipes heading into pcv
     

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