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which sensors control Fueling? 2.0TFSI

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by spider74, Aug 6, 2012.

  1. spider74
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    spider74 Member

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    [Aug 6, 2012]
    Tried posting this in the technical section but it seems very little interaction way down there!

    I’m looking to understand which sensors control the fuel mix on the 2.0tfsi engine.

    MAF, Coolant temp and what else?

    A4DTM 2.0TFSI Quattro

    My car seems to be running rich, it keeps fuelling on no throttle giving some burps etc on engine braking (which it didn’t before) and has a throttle lag then a sudden boost!.

    Also puffs some smoke out if you have been cruising on part throttle and floor it.

    It doesnt smoke at all on full throttle just a fter a period (10 mins) of partial throttle cruising I have VCDS and checked the throttle alignment and position sensors and they seem fine.

    Car makes boost and I have a boost leak test kit so it’s not a boost leak.

    Unplugging maf improves things so I cleaned it using MAF cleaner. Worked a little but not back to the way she was.Planning to use my usual "replace the cheapest thing first and work up to the most expensive" so any help appreciated.

    Car still drives great and is fast but something is not right. Happened when i was overtaking on the motorway a few weeks ago. Symproms were surging boost at mid throttle. I can drive round it but i get the feeling it could be something daft. (last thing, it drivesbetter when cold, although i never WOT before its up to temp. )

    Many thanks







    Last edited: Aug 6, 2012
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  3. hades-
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    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [Aug 6, 2012]
    MAP ?
    i had this on my fsiT some time ago ended up been a bad MAP sensor
    (no fault codes showing)
    #2
  4. spider74
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    spider74 Member

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    [Aug 6, 2012]
    thanks Bez, i'll start with that one then! Where is it in the TFSI? im assuming on the intercooler piping post turbo? Is it the same thing as the boost pressure sensor? I'll have a search. Thanks for helping :)
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  5. hades-
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    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [Aug 6, 2012]
    yes i think its the same thing
    off hand im sure its down the pass side to the front near the headlight
    #4
  6. spider74
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    spider74 Member

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    [Aug 8, 2012]
    ah well put the new map sensor in last night and although i was determined to feel it was fixed it isnt :( however you live and learn as im certain its temperature related. when cold even when the temp needle is at 90 but the oil temp perhaps isnt up to full temperature things are smooth. Im going to try the coolant tempera
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  7. jonny87
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    jonny87 Active Member

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    [Aug 8, 2012]
    Pre cat/post cat lamdas?
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  8. spider74
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    spider74 Member

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    [Aug 8, 2012]
    got cut off half way through my message, meant..

    try the coolant temperature sensor, fuel temp sensor, manifold air temp sensor and possibly MAF again. Managed to persuade my mate whose wife has a 2.0tfsi to let me try a few from her car to help the process. MAP sensor was a good call though BEZ as its made a difference.

    Also the lambdas i have two one pre cat and oene post however the post is mapped out as i have no cat so i suppose i could swap them round? see if that helps? Thanks for the help folks, as i say the car runs ok just not right. v frustrating that it throws no codes. However thats why this forum is so great at helping us to avoid the £100 per hour Audi charges! :)
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  9. mancdan
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    mancdan Member

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    [Oct 17, 2012]
    What doe MAP stand for?
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  10. Michaelkirkup
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    Michaelkirkup New Member

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    [Oct 17, 2012]
    Map is manifold absolute pressure mate
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  11. mancdan
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    mancdan Member

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    [Oct 18, 2012]
    Cheers Michael.
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  12. prel2000
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    prel2000 Member

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    [Oct 18, 2012]
    I'll be interested to see which action resolves your issue as I am experiencing similar symptoms with mine. Thanks
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  13. Scott.T
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    Scott.T Member

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    [Oct 28, 2012]
    Has this been resolved yet as I'm chasing a 1,700rpm to 2,300rpm light missfire that flags no codes and it's not coil, plugs, MAF, DV of throttle pot. Throttle Body has also been cleaned.
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  14. hades-
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    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [Oct 28, 2012]
    have you checked the HPFP cam follower ?
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  15. Scott.T
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    Scott.T Member

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    [Oct 28, 2012]
    No, is this easy to do.
    I have heard of it wearing but no idea where to locate it, other then down the back of the engine somewhere.
    Does this also increase the engine rattle when worn, as it may be another sympton.
    #14
  16. hades-
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    hades- Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [Oct 28, 2012]
    #15
  17. Scott.T
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    Scott.T Member

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    [Oct 28, 2012]
    Cheer's had a google to and it seems quite straight forward.
    Would like to know what the symptons and side effects are.
    #16
  18. spider74
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    spider74 Member

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    [Mar 16, 2013]
    Took me ages to get to the bottom of this but it was the thermostat. Car was running cold. £30 part. I also replaced the cts which showed up the problem more (old sensor might have been bad) and then logged engin temps with vcds. Temp fluctuated between 60 and 80 deg even on a long run.
    #17

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