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Car goes limp over 8 psi

Discussion in 'A3/S3 Forum (8L Chassis)' started by Maccabee33, Jan 15, 2012.

  1. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Ok so no idea if this is right but my car at the moment only boosts to 5 psi. I'm sure from what I have seen on here thats wrong! I have fitted a MBC and it does as it should and I can get upto 10/15 psi. How ever when I do this as soon as the boost reaches anythink over 8 it goes limp and feels like some giant is pulling the car back.

    Anyone got any ideas?? As I said before I have no idea what it is but it's almost like the car is cutting the fuel.

    All help will be greatly received.
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  3. sportstractor
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    sportstractor Chugger

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    [Jan 15, 2012]
    Have you been able to have it scanned for faults? Also why are you running a MBC?
    #2
  4. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Jan 15, 2012]
    Have you fitted the mbc right? And like said, why have you fitted one?
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  5. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    I only put it in to see if it would go over 5 psi as I thought it was odd that it's was only boosting at that.

    I have been doing more reading and I'm not sure if it's related to my maf as I have had to disconnect it because its faulty and haven't had a chance to get a new one.

    I haven't been able to have it scanned either I should be able to get my mate to do it at some point this week I hope.
    #4
  6. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 15, 2012]
    If you have fitted the MBC without the car being mapped then its hitting limp mode... you cannot just fit an MBC on a std map... it simply doesn't work...

    <tuffty/>
    #5
  7. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Jan 15, 2012]
    So prior to fitting the mbc your car was only making 5psi?
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  8. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    Has this car been remapped yet?
    #7
  9. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    No no remap it is planned. I wasn't using the MBC to gain more boost in that way just to see if it would go over 5psi and yes dani it was only hitting 5 iv not noticed any loss of power since iv had the car and it's always been the same ever since I put the boost gauge in
    #8
  10. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Jan 15, 2012]
    Well that sounds like the cars running on actuator pressure, so either the n75 valve isnt plugged in or its knackered and you need a new one.
    #9
  11. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    I did think it may be that but then loads of post say they don't fail that often. Iv tried running it unplugged and the same. I have also diverted it and it still only hits 5 I'll get a new one and try that. Is there anypoint getting a aftermarket one ? Iv seen people say not to.
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  12. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 15, 2012]
    First off... what engine code? what car? what year? difficult to begin to suggest anything without knowing...

    Reading back through some of your previous posts it seems you have bee hacking into various pipes to fit a boost gauge... did this problem happen before or after fitting the boost gauge?

    Have you put the N74 pipework back to how it was? from what I read you didn't connect it right... incorrect pipework on the N75 may well be the problem here if not..

    <tuffty/>
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  13. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    No car felt the same before adding the boost gauge. All pipe work is completely back as before except for joining piece. With clamps. And boost gauge in. Correct place. Its a V reg I think 99. 1.8 t front wd 150bhp.

    Sorry I know you guys must be going bad about how car retarded I am. I work on tech support so I know the feeling and I apologise.
    #12
  14. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 15, 2012]
    seriously dude, you're asking about boost issues, and playing with an MBC, whilst all the time your MAF is unplugged?

    Why even bother asking for advice.....

    ''Guys, I have severe trouble walking, please help''

    ''hmmmmmmmmmmmmm, I can't think what your problem would be Sir, can you give us more information''

    2 hours later......


    ''oh, by the way, I've got no legs, don't know if this matters''

    Fix the known faults before trying to solve the unknown.....
    #13
  15. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 15, 2012]
    Sorry if that sounded arsey. it wasn't intended that way, but you'll never have any joy chasing problems if you have existing known issues in the first place.
    #14
  16. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 15, 2012]
    All good bud... we all started somewhere :D

    If its an AGU then chances are the MAF is a little tired... the MAF's on AGU's control just about everything... I would grab a copy of VCDS or find someone that has it and get the car scanned for fault codes...

    <tuffty/>
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  17. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    I wouldn't worry too much dude, just stop doing things the **** bodging way and get it mapped properly from here on in. There are people who think they can do all this themselves, and it always ends in disappointment and tears.

    Take the MBC back off, get a new MAF and see if it still runs into limp mode. Then go and get it scanned properly, and assuming it runs normal with the MBC off and the fault codes removed go and get it remapped.
    #16
  18. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    It was doing it before the maf was unplugged or had a problem. I totally understand I'm annoying myself on how little I know or I can assist
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  19. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    Get a new MAF, if it was doing it before the MAF was unplugged...and the MAF was unplugged because it was faulty...and it's still doing it now without the MAF...you do the math. :icon_thumright:
    #18
  20. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Thanks <tuffty/> I saw a post today about cleaning the maf so was going to do that to see if it sorted it.

    It's odd that defore I had a problem with the maf it was still running at 5 psi. I'll have a look tomorrow and see what engine it is.

    Thanks for your help


    16klappe I'm going to don't worry! Just got the clear the bar tab first so I can pay for it ;)
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  21. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    Out of interest, if you haven't got VCDS how do you know the MAF is faulty? Why did you unplug the MAF?
    #20
  22. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Car was cutting out randomly then got really bad and was stopping staring. Had my friend an actual mechanic have a quick look. Unplugged maf problem goes away. It was shutting its self off foursome reason. He said to get a new one just not had the chance and not going to lie wile it was running ok I have left it will get it sorted now I know how much it's controlling.
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  23. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    And have you tried plugging the MAF back in? How do you mean "it was shutting itself off"?
    #22
  24. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Yeah as soon as I do the car won't start or if you have the car running it stalls when plugged back in. Not 100%as I'm sure is obvious haha. It closes the part inside ??? I assumed it was lack of oxygen. Wouldn't be suppressed if I was completely wrong
    #23
  25. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jan 15, 2012]
    A duff maf can make the car chop out. My last one did it. With the maf disconected you'll be lucky to see 5 psi. Stick a new bosch replacement and your massive 8psi will be restored assuming nothing else is broken
    #24
  26. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Awesome thanks dude! I'll get that ordered up. Then I can start looking for some ware close to get a remap done.

    Any one know any in Hampshire/ Berkshire Basingstoke area ideally
    #25
  27. superkarl
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    superkarl MAN OF STEEL

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    [Jan 15, 2012]
    Report back after a maf first! :) lol
    #26
  28. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 15, 2012]
    dude, did you want to try a different maf first and see if it helps things?

    I'm in Basingstoke, and have a MAF that's not being used until next weekend if you want to try it..... Could also plug it into Vagcom and see what's coming up.....

    Remap places close to you are Storm developments in Aldermaston, or JKM in Pompey
    #27
  29. Maccabee33
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    Maccabee33 New Member

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    [Jan 15, 2012]
    Awesome yeah that would be good! We're abouts in Basingstoke are you? Storm the guys that do the superchargers? They are just down the road from work. Perfect :)
    #28
  30. 16Klappe
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    16Klappe Princess Clap.

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    [Jan 15, 2012]
    You can usually find him parked up just over the motorway bridge going up to Farley Mount, about 9PM on Tuesday nights. You'll know it's him because he'll have his interior light on whilst he reads the paper.
    #29
  31. Maccabee33
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    Maccabee33 New Member

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    [Jan 16, 2012]
    Yeah hooked the maf back up and no engine start. Took it off and had a look.... The sensor had half broken off god knows how but I'm defiantly off to get a new one now!
    #30
  32. A3AH
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    A3AH Member

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    [Jan 16, 2012]
    ftr, when i changed my MAF sensor, i stopped going into limp mode.
    #31
  33. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 16, 2012]
    haha, thanks Jardo. charming.

    I'm in Hatch Warren mate, a few hundred yards from Sainsburys. What about you?
    #32
  34. Maccabee33
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    Maccabee33 New Member

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    [Jan 17, 2012]
    Oh right I think I know. Don't no Basingstoke to well only just moved here. Even though I did used to live in kingsclere I never really explored much. I'm up behind the station A couple of roads down from the vine ?
    #33
  35. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 17, 2012]
    Google maps... its the future :)

    <tuffty/>
    #34
  36. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jan 17, 2012]
    AGU

    dont just up the boost
    not advised..
    get it remapped properly
    it will end in tears else
    #35
  37. Maccabee33
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    Maccabee33 New Member

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    [Jan 17, 2012]
    Thanks badger 5. That's what I'm planning on doing. Storm devopments are meters away from my work and have a deal on a stage 1 for £148.
    #36
  38. Maccabee33
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    Maccabee33 New Member

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    [Jan 26, 2012]
    Maf swapped much nicer but same problem. Put MBC in place of n75 as test and runs fine at normal boost. So of to get a new n75 now will post progress
    #37

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