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A3 TQ Re-map problem

Discussion in 'A3/S3 Forum (8L Chassis)' started by , Apr 16, 2005.

  1. Online

    Guest

    [Apr 16, 2005]
    Guys,

    Had my AJQ engine 18TQ remapped today at AMD... now i have a strange problem

    The boost seems to come and go as it pleases, the car can be very wobbly accelerating (i.e goes, then goes not as fast, then pulls hard again, then split second power drop, pulls hard so on)

    It just hesistates for a split second every now and then, sometimes once in each gear, sometimes not at all and sometimes it does it so bad it feels like a stock 1.8 non turbo

    Problem seems to come and go, sometimes will be wobbly, sometimes seems to only boost like half what it should be...

    Ive been told that i had a lambda sensor fault code on the car, but i also had a leaky turbo gasket so the car might have been thinking it was getting more air than it was (Due to leak) confusing the lambda sensor? (not sure how the Audi ECU works)

    anyway, ive also seen this could be the knock sensor? and also maybe the N75?

    Does anyone have any info on the N75 as i cannot find any, what does it do?

    and also, can anyone think of anything else it could be?

    Cheers
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  3. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Apr 17, 2005]
    Sounds like the 'classic' MAF sensor failure, that's what it felt like for my S3 after the remap, power was hesitant and on and off as you described, worth a look /ubbthreads/images/graemlins/beerchug.gif
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  4. foolish3uk
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    foolish3uk Member

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    Guest

    [Apr 17, 2005]
    ok cool, how much is this, where is it located and is it difficult to fit?

    i hear you need to plug these cars into a diagnostic machine after changing a sensor to generate a "resonance code" or something stupid, is this true?!

    if so, will the car run well enough to drive it to a garage?

    Also, if you could describe the prolem YOU were having, like when it had the problem and when it didnt (what gears etc, throttle so on) i would appreciate it, just so i can tie it in.

    thanks
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  6. Online

    Guest

    [Apr 17, 2005]
    ok, been doing some searching and found a lot of posts about cleaning the MAF.

    I tried cleaning mine (this is the big tube that screws onto the airbox, right? like an air flow meter?)

    anyway, got the actual sensor out and there isnt alot thats cleanable - at the bottom i can see a metal bar and 2 or so more behind it. I could only clean the first though because i couldnt get to the two behind them. There was also a metal plate running along the side of the sensor cleaned this too.

    no diff...am i cleaning it wrong?

    Going to go down to motor factors tomorrow and see about a new one....
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  8. benk
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    benk Member

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    [Apr 18, 2005]
    I recently cleaned my MAF and it made no difference. After getting a new one put in last week I notice that the car has got some balls back - much better power pickup around 2500 revs and less lag above 3000.
    Mine was 75 pounds exchange via Audi. They are about 200 quid for a new one but almost all are exchange from what I hear.
    You can call your local Audi dealer and speak to the parts person: with your chassis number or engine code they should be able to tell you whether your MAF is an exchange part or not.
    Being exchange of course, you don't get to keep the old one, so if this isn't your problem, you may have spent the money just to renew a part that might not have needed it yet. It's a one-way ticket.
    #7
  9. Online

    Guest

    [Apr 18, 2005]
    ok...thanks for the Info.

    Jojo - can you describe your problem please? I just really need to tie this in!!

    The problem on mine is strange, it only seems to really occur over 4k...

    you put your foot down, power comes in a big surge around 3k ish then tails off from that point onwards....

    does this sound liek the MAF?
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  10. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Apr 18, 2005]
    [ QUOTE ]
    ok...thanks for the Info.

    Jojo - can you describe your problem please? I just really need to tie this in!!

    The problem on mine is strange, it only seems to really occur over 4k...

    you put your foot down, power comes in a big surge around 3k ish then tails off from that point onwards....

    does this sound liek the MAF?

    [/ QUOTE ]

    Just as you described it really, with car bunny hopping up the road as you go through the revs, kind of a misfire or under fueling feeling if you know what I mean?!
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  11. Online

    Guest

    [Apr 18, 2005]
    ok; i've replaced the MAF at a cost of £80 (on the credit card /ubbthreads/images/graemlins/frown.gif) and its not done sh*t!!!!

    Car is still exactly the same...next point of call is the N75 valve, a friend is borrowing one form work (he works at a seat garage) and we will see if this solves it.

    Cant believe ive just wasted 80 quid on nothing though...oh well, can't be helped. Problem is now if the N75 valve sorts it i haven't the money to pay for it! /ubbthreads/images/graemlins/frown.gif

    Ill keep you all posted, any other suggestions welcome though.
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  12. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Apr 18, 2005]
    [ QUOTE ]
    ok; i've replaced the MAF at a cost of £80 (on the credit card /ubbthreads/images/graemlins/frown.gif) and its not done sh*t!!!!

    Car is still exactly the same...next point of call is the N75 valve, a friend is borrowing one form work (he works at a seat garage) and we will see if this solves it.

    Cant believe ive just wasted 80 quid on nothing though...oh well, can't be helped. Problem is now if the N75 valve sorts it i haven't the money to pay for it! /ubbthreads/images/graemlins/frown.gif

    Ill keep you all posted, any other suggestions welcome though.

    [/ QUOTE ]

    Sorry to hear that it's made no difference mate, hope you get it sorted soon! /ubbthreads/images/graemlins/thumbsdown.gif
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  13. DuncS3
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  14. Kevint
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    Kevint Active Member

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    [Apr 18, 2005]
    Has this happened as soon as the remap was done, or did it appear soon after?

    Kev.
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    Guest

    [Apr 18, 2005]
    Ok, ive now done the N75 valve and MAF, problem still evident.

    This has happened AFTER the remap...ish.

    Basically, the gasket between the turbo and exhaust manifold was leaking (causing loss of boost, obviously)

    I had the remap done with it in that state, the car went ok. As soon as i replaced the turbo gasket (so car now runs full boost) the problem became evident.

    I did the gasket the day i had the remap done
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  16. Kevint
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    Kevint Active Member

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    [Apr 18, 2005]
    If it happened immediately after the gasket, it sounds like the problem occured then, but that could just be conicidence.

    I've had 3 lamda sensors fail in my old A3 (non turbo). Intermittent power, sometime drives fine, othertimes like a pig, kangarooing etc.

    Kev.
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  17. Online

    Guest

    [Apr 19, 2005]
    Kevint, the car was loosing boost because of the leaky gasket. Now it is getting full boost i think the car may be getting confused or something.

    Could be a lambda sensor, i need to get it on VAG COM next week to check for faults...

    I don't know whats causing it, its very irritating.
    #16
  18. Online

    Guest

    [Apr 20, 2005]
    Anyone have an opinion on if a faulty lambda could be causing this?
    #17

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