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  1. #1
    S3 TAM's Avatar
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    limp mode of some sort

    Hi,

    Yesterday I drove my car on a airfield.

    I floored it up and down hitting speeds of around 140-145 but after a couple of runs my car seemed to go into a limp mode cutting boost to around 14 psi "normal boost is around 19-20psi".

    Has anyone got any ideas why it would do this?

    I thought it might be something to do with heat but not sure because limp mode kicked in after 2 runs all in all about 3-4 minutes. Is this normal?

    I turned the car off for about 5 mins and was back to normal.

    This has happened before when giving it a bit on the motorway aswell.
    Could it be my map. I don't know who did the map as it was mapped when I bought the car. Is there anyway of finding out?

    I thought I would be able to give the car abit more stick.
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




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  3. #2
    Jimmeh's Avatar
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    I recently decided to be a bit of a hooligan (on my private test track!!) pushing speeds of 120 whilst catching a friend early hours one morning.. Around 118, my pedal dropped from beneath me; massive loss of power. Limp Mode was activated and I nursed the car back into the pits

    I had a map done not long ago - it's as though it'd just "Fell off" the end of the map. Not sure if this is possible?

    Will keep an eye on this to see if you get it fixed (can't say i'll be pushing those speeds again anytime soon but it's nice to know it's not broken for peacer of mind!)
    Audi A4 Avant 1.9TDi 130 Quattro Sport.
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  4. #3
    S3 TAM's Avatar
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    Sounds very similar to me. very strange indeed hope fully we will get some answers was thinking of getting my map changed to a REVO.
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  5. #4
    evilscotsman's Avatar
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    you need to vag com it for proper codes, most likely it was overboost or the maf is flaky. You need to log requested verses actual on maf airflow, fuel pressure and boost pressure amongst other things, the cause will show up.

    Start logging and do a 3rd gear pull from as low revs as you can and then check the graphs when it goes into limp, may have to do a few runs but limp mode wont break anything itself, rather the ecu is trying to protect the engine from damage due to some condition it sees.
    B4 TDI - old skool project / daily driver...if it ain't broke, it's probably an Audi...


  6. #5
    S3 TAM's Avatar
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    Quote Originally Posted by evilscotsman View Post
    you need to vag com it for proper codes, most likely it was overboost or the maf is flaky. You need to log requested verses actual on maf airflow, fuel pressure and boost pressure amongst other things, the cause will show up.

    Start logging and do a 3rd gear pull from as low revs as you can and then check the graphs when it goes into limp, may have to do a few runs but limp mode wont break anything itself, rather the ecu is trying to protect the engine from damage due to some condition it sees.
    Cheers I'll do some logging at the weekend. hopefully it will show something. but the car only goes in to limp mode after a 2 minute burst at near top speed roughly.
    shall i do that then log in 3rd gear?
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  7. #6
    evilscotsman's Avatar
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    well, I would log any run thats likely to trigger limp mode mate, 3rd is the normal diagnostic run to do but you can save that then do a top speed run till it limps and compare them, looking for a difference between requested and actual for each run, as opposed to just differences between the 2 runs, but when it goes limp the boost will cut, i'd be looking for anything that was wrong just before the ecu cuts the boost, like req and actual boost being way different then bam, limp mode etc.

    If it doesnt hit limp, you may still see a problem, likely the maf, but you never know and a lot of maf errors such as low readings at high airflow, wont throw a cel themselves as the sensor "seems" to be working to the ecu, its just supplying bad info at certain airflow levels say.
    B4 TDI - old skool project / daily driver...if it ain't broke, it's probably an Audi...


  8. #7
    S3 TAM's Avatar
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    right i need some help with this. I don't seem to be getting anywhere.
    Before i went out i scanned fault codes all clear.
    Car boosts fine 19-22 psi, until somewhere around 130-140 then all of a sudden boost cuts completey after a milisecond give me 13-14psi.
    rescanned for fault codes nothing. logged the MAF getting around 208G/S till boost cut then around 170 g/s. this seems to be about right to me seeing that the car is boosting less so it wants less air? is this correct?

    I also logged block 120 in "limp mode" it reakons i'm getting around 190 - 200bhp.
    I think this is not a mechanical issue but maybe something todo with my map almost like it switchs to the standard map in a split second.

    can anyone suggest what blocks to log to give me some better information on whats happening leading up to my boost cut?

    Cheers
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  9. #8
    ben.w93's Avatar
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    Coils possibly, my a3 did a similar thing, I replaced the coils and now its fine.
    2008 A5 3.0TDI


  10. #9
    superkarl's Avatar
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    coils would cause misfire, one of mine packed in today.

    is it possible for the map to just switch off, i wouldnt have thought possible.

  11. #10
    S3 TAM's Avatar
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    I dont think its the coils becuase its not a misfire. I dont know how maps work but do they have a end point like a limit to the software? Why does it stay in limp mode for a while?
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  12. #11
    <tuffty/>'s Avatar
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    If your S3 is a facelift that comes with an EGT probe then it could be EGT's getting too high and ECU protection kicking in... I had similar on mine for a while...

    Log block 001 (lambda control value), 031 (fuel request vs actual), 112 (EGT's)... if high EGT's are causing this I would expect that once the EGT value gets to 925 degrees and over block 001 will freeze the lambda control value and block 031 will show something in the region of 0.75's on actual fuelling... this the ECU hitting a protection map to get the EGT's under control by flooding the engine with fuel...

    <tuffty/>
    Silver 2001 AMK S3. Silver alcantara interior... now with added powarrrrrrrr, torques. VAGCOM + KII-USB. >> My build thread...

  13. #12
    S3 TAM's Avatar
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    Cheers Tuffty

    This sounds about right to be honest. I'll log tonight if i get a chance. what did you do to resolve this issue?
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  14. #13
    <tuffty/>'s Avatar
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    Quote Originally Posted by S3 Baby View Post
    Cheers Tuffty

    This sounds about right to be honest. I'll log tonight if i get a chance. what did you do to resolve this issue?
    Fit a bigger turbo

    .....or....

    FMIC and a 3" DP will help as would a proper manifold (when a decent one actually becomes available!!), water meth will help keep things cool but tbh a stage 1 mapped car 'should' be ok....

    See what the logging suggests first...

    <tuffty/>
    Silver 2001 AMK S3. Silver alcantara interior... now with added powarrrrrrrr, torques. VAGCOM + KII-USB. >> My build thread...

  15. #14
    S3 TAM's Avatar
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    Quote Originally Posted by tufftybloke View Post
    Fit a bigger turbo

    .....or....

    FMIC and a 3" DP will help as would a proper manifold (when a decent one actually becomes available!!), water meth will help keep things cool but tbh a stage 1 mapped car 'should' be ok....

    See what the logging suggests first...

    <tuffty/>

    I would love to get a bigger turbo but my pocket not big enough yet..

    FMIC and 3" DP it is then any suggestions on decent ones.
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  16. #15
    finesse's Avatar
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    hybridize your turbo ;p

  17. #16
    <tuffty/>'s Avatar
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    Quote Originally Posted by S3 Baby View Post
    I would love to get a bigger turbo but my pocket not big enough yet..

    FMIC and 3" DP it is then any suggestions on decent ones.
    AH Fabs FMIC and Pipeworx DP are as good as anything else out there... see the FMIC thread in the stickies

    <tuffty/>
    Silver 2001 AMK S3. Silver alcantara interior... now with added powarrrrrrrr, torques. VAGCOM + KII-USB. >> My build thread...

  18. #17
    S3 TAM's Avatar
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    Quote Originally Posted by tufftybloke View Post
    AH Fabs FMIC and Pipeworx DP are as good as anything else out there... see the FMIC thread in the stickies

    <tuffty/>
    Yeah i've been doing my research today. thats sounds about right. spoke to pipeworx they quoted 500 3" DP, sports Cat, poly dog bone.
    not sure about fitting it, they are abit far for me to travel. don't fance doing it outside my house on my back with no room to move. LOL

    I havent got on the phone to AH Fab yet might aswell wait till payday not long yeah.
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  19. #18
    S3 TAM's Avatar
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    right i've finally got round to logging.

    Tuffty i logged what you said 001,031,112. my EGT hit 925 but i can't see what else is happening in the data.

    could someone have a look please.

    you can download my excel file from

    2shared - download logmax edit.csv


    cheers
    Revo Stage 2 with all the Gear
    BHP = 274 / Torque = 293




  20. #19
    finesse's Avatar
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    try sendspace.com cant download

 

 

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