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Strange Loss of Boost?

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3 Paul, Nov 30, 2009.

  1. Broken Byzan

    Broken Byzan Photographic Moderator
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  3. Effect

    Effect Member

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    I dont believe for one second that these pipes will cure your problem.

    Good luck anyway and keep us posted bud.
    I have the same map and exactly the same problem as you and I just want to know what to do to get it fixed :)
     
  4. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Urrrrm not being funny but I also dont believe this is the overall issue as split pipe would cause it all the time, not on just cold mornings etc, also rubber pipes in the cold surely would be more rigid thus the split wouldnt be so apparent, when engine warmed up then the rubber would be softer thus would open easier, but of course its speculative & how much of a vacuum are the pipes handling as such.

    Also is this a reason for them to charge for there time aswell, have to think about this from every angle.

    The last angle is, have they said there were split pipes but they've actually truthfully tweaked the map further.

    This all comes down to trust & so far given the service received I wouldnt have much faith overall, but then again maybe a nice xmas present if its fixed & maybe no bill, strange the pipes all of a sudden have a split huh :detective2:
     
  5. S3 Paul

    S3 Paul Well-Known Member
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    Right,
    I maybe need a hat...
    Ive been up to JBS today, Quite an eye opening day with regards my car...
    Firstly... the pipes that had split was down to me over tightening hose clamps. So did need replacing and have been done,
    Secondly , and more importantly the "issue" im having i will now say isnt down to the the map after all. The car has been flashed back to standard and... still the fault apears. So thats one thing off the list ! In adition... after some testing by Kev and James they have found that the car throws up this fault befor the car is even started. Turn on the ignition... code is thrown up. Clear the code turn off the ignition turn it back on.... there it is again!

    The "preasure drop between throtle valve and turbo" fault code is confusing as ( as far as i can see ) how can there be a preasure drop when the car hasnt even started ?
    So... After a lengthy and in depth chat with James i agree with his thinking that this is very likely down to a sensor breaking down or giving a bad voltage signal to the ECU . A few were mentioned ... MAP sensor. Coolant temp sender. Oil temp sender but time will also be spent checking the throtle body for either malfunction or misalignment.

    The fact it only happens on a cold day... well this could be down to cold damp air in or around the sensor?
    The limited boost is because the car has gone into "soft limp" ... Im thinking when the ignition is turned on the ecu does a check of all sensors and is getting a slightly dodgy reading maybe? due to the sensor dying?? but thats me speculating.

    Anyway, ive got the car back as they are shut over christmas and in this weather the use of a awd car is a great relief. With the vacum leaks sorted the car does feel alot better . The old girl is back there on the 5th for the mentioned sensors to be checked .

    In short i think ive jumped to the conclusion i had the same problem another member had as it made sence to my untrained eye.

    In the same way one tablet will not cure all illness, Removing or reworking a line or two of code will not fix all fault codes.
    So... im not going to guess whats up... but i sure will let you know what it turns out to be.
     
  6. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    Glad to hear you are on the road to getting it all sorted mate...

    Fair play, always something different on these cars that seem to show the same symptoms and lead you on a merry dance....

    In fairness though, I am not sure what sort of a valid test flashing back to std will be on your car as you have a fair few mods.

    Call me a sceptic but I will hold out for the final verdict before giving you some links to online hat shops. As I have said before, nothing surprises me with VAG cars anymore.

    I hope you get it sorted as there does not seem to be any logic to this at all... Fairly sure moisture etc isn't the issue... this code is thrown when the frost warning is on (5deg or below) so logic would state would be to understand what happens in the software under these conditions and start back from there. Reeling off random sensors isn't the right way about it in my book tbh...

    Good luck and have a good christmas..

    <tuffty/>
     
  7. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Well been studying etka for an 01 car & 1.8T engine setup as I dont know your engine code, found a Thrust Sensor which is positioned (on amk/bam/aul engine codes) on a pipe leading from an IC, so maybe its this as what else can sense between turbo & inlet, I cant see another sensor except the N75 valve I think.
     
  8. badger5

    badger5 www.badger5.co.uk
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    thrust sensor in an ic pipe i am guessing is a poorly translated map sensor perhaps..

    i know when i order n75 valves they come labelled as dump valve from vag..duh! lol @ vag
     
  9. NHN

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    Yeah when I saw that name I was like, urm typical germans, thats etka for yer.

    I'm hazarding a guess this could be at fault no, given what it does, maybe the cold weather is throwing an intermittant fault with this huh, speculative but possible given fault.
     
  10. S3 Paul

    S3 Paul Well-Known Member
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    Well kev did say it may be the map sensor or one of the other things i mentioned. I said "stick me a map sensor in then and i will see how i get on" But both kev and James said thats a bit of a silly way to go about things as it could well be me just wasting money blindly chasing a fault.

    Tuffty,
    Regarding flashing the car back to its fully stock map , This was to show... that the fault wasnt within the map as the stock map was the one i had on the car from audi. The car doesnt even need to be run to throw the fault up. Simply turn the ignition on and read the faults... then clear it and repeat... it pops up when ever the ignition is turned on witht the temperature being below 5 degree.

    The hoses that needed replacing must have been the cause of the car not making the requested boost ... because its a flys now !

    Bring on the 5th of january...
     
  11. S3RYAN

    S3RYAN New Member

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    Joined a bit late in the game here. I'm suffering similar problems
    Fault code - boost pressure between turbo and throttle control (check D.V.)
    Goes into limp mode as and when it sees fit until it gives up the ghost completely, stays in limp mode and eventually throws the engine management light
    Visit my mate with VAG-COM, clear the fault, back to the same behaviour

    I've replaced the MAP sensor, MAF sensor, N75, coolant temp & recirculation valve so far...
    The problem started with a boost control valve error that transpired to be a split in the vaccuum pipe that runs under the inlet manifold
    It ran fine for ages after we fixed the split pipe
    Now we have the pressure being lost code
    Mine's totally standard and the limp mode isnt that apparent when you watch the speedo. You can definitely feel it though.

    Not sure if its related, saw something in the thread about a pipe under sump guard and I know occasionally when I hit a deep puddle it runs like a dog for a couple of minutes.
    I just want it to be back to how it used to be. Do I just have to bow to the 80K rule?
     
  12. S3 Paul

    S3 Paul Well-Known Member
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    Well, Quick update,
    Ive had the car back a week now,
    The work carried out on the cars last visit to JBS was... to test and try a replacement of the mentioned sensors, One at a time and left over night to sit in the cold weather. None of the sensor replacement help so back in with the ones i had already had, Kev did notice that some of the plugs to these and other sensors didnt feel possitive so this would be his next area to work on, After cleaning and closing each plug in turn im happy to report the car hasnt dropped into the dreaded limp mode since. I have seen temperatures between 0 and 3 degree the days i have used the car. So heres to hoping its finaly sorted.
    I take my hate ( prior to eating it ) off to Kev and JBS for tracking it down !
     
  13. badger5

    badger5 www.badger5.co.uk
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    as a matter of interest what max airflow and boost does your move these days?
     
  14. Effect

    Effect Member

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    Is the car still behaving ?
    Have you had the remap put back on yet ?


    James
     
  15. badger5

    badger5 www.badger5.co.uk
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    bump..
     

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