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Questions about removing MAF

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by monz87, Apr 18, 2012.

  1. monz87
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    monz87 Member

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    [Apr 18, 2012]
    Hey guys, just wanted to ask a few things about the MAF.

    I have a 2006 A4 2.0T FSI Multitronic S-Line.

    I've got another thread about poor MPG - 12.67MPG to be exact! Anyway the car runs absolutely fine and smooth and power is there. There are no warning lights on either. Only problem is that it is drinking big time and I aint thrashing it just normal driving with the occasional pulling.

    I wanted to take out the MAF and see if there is any difference, even clean it, but first of all;

    - Where is the MAF and how do you take it out?
    - Even though the car seems to run perfect aside from bad MPG and that there are no warning lights on, could the MAF still be dodgy?
    - If it is the MAF, and I took it out, then would the car still drive normal but fuel consumption improve? Or what actually happens if you drive without a MAF and how could that impact the MPG considering no warning lights are on and car seems to drive fine?
    - Will the car then give me a warning light that that MAF has been removed and leave that light on there even if I put the MAF back?
    - Will a VCDS be able to identify a dodgy MAF?
    - Finally, if it were the MAF, and I took it out and gave it a clean, would I notice an improvement when I took out the MAF or when I cleaned it and put it back?
    Last edited: Apr 18, 2012
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  3. Sandra
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    Sandra MODERATOR Staff Member Moderator

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    [Apr 18, 2012]
    #2
  4. monz87
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    monz87 Member

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    [Apr 18, 2012]
    Many thanks Sandra, unfortunetely nothing about MAF :( But I have bookmarked that great site :)
    #3
  5. Sandra
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    Sandra MODERATOR Staff Member Moderator

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    [Apr 18, 2012]
    Sorry it didnt work out for Maf info, but it is a fantastic site for mostly anything in the A4 range. :)
    #4
  6. monz87
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    monz87 Member

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    [Apr 18, 2012]
    yeh definetely, always good to have them bookmarked :D
    #5
  7. monz87
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    monz87 Member

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    [Apr 19, 2012]
    No one knows anything about MAF ???
    #6
  8. scrag
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    scrag New Member

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    [Apr 25, 2012]
    im not sure of the 2.0t but i unplugged mine on a 2.5tdi and noticed it ran and revved up better....but seeing as its tiptronic it throws the gearbox into limp mode when unplugged,so i couldn't drive it to check.

    but i fitted a pierburg maf and blimey..........its made one hell of a difference to performance.....

    they are fitted in a tube just after the air box on the 2.5.....good luck!
    #7
  9. monz87
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    monz87 Member

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    [Apr 25, 2012]
    To be honest I still don't know where it is do you think you could show me where it is on a pic or something? Also is it easy to take on and off, I just want to clean it and put it back on. Finally do you get any warning lights on?
    #8
  10. ben.w93
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    ben.w93 Member

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    [Apr 28, 2012]
    Its on the end of the air box, it goes between the black hose and the airbox, here is a pic of of one on an A3 2.0TQ, (they are the same part). I had to borrow one out of an A3 when I had problems, turned out it had blown one of the intercooler hoses off.

    [​IMG]
    Best thing to do is remove the air box, cant remember if they are torx, but to remove the MAF sensors, you will possibly need the security torx bits.
    Here is a photo of my air box removed, its quite easy to take it out.
    [​IMG]
    Hope that helps a bit.
    Last edited: Apr 28, 2012
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  11. ben.w93
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    ben.w93 Member

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    [Apr 28, 2012]
    By the way, when i was trying to diagnose my fault, it was really bad on fuel when I unplugged the MAF, you could try cleaning it, I cleaned mine because it had a K&N fitted on the car when I bought it :no:. Mine didn't like having the MAF unplugged, it bought up the engine management light. When was the car last serviced, mine is much more responsive after it was serviced, I'm running on superunleaded too, my fuel economy seems to be ok. I think the warning light turns itself off once plugged back in, you might need to restart the car after plugging it back in for it to clear though.
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  12. monz87
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    monz87 Member

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    [Apr 28, 2012]
    Well my car is still at the dealers for the warranty repairs, when it comes back, I may give it a shot if the fuel consumption still hasn't improved or I may try it anyway.

    If I take it off and clean it, do I clean just inside the MAF with MAF cleaner or also inside where it connects in the car to?

    And if I clean it and put it straight back on without turning the car on while its off, will that bring on any warning lights?
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  13. ben.w93
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    ben.w93 Member

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    [Apr 28, 2012]
    When I cleaned the the MAF sensor I spayed the outside of it with carb cleaner and the square cut out towars the end, but I also did the housing and the inside of the airbox and changed the filter as it was coated in oil from the K&N. You need to be careful when cleaning them because they can be damaged quite easily by all accounts and they are £100+ to replace I think. I have not tried disconnecting, cleaning and then reconnecting it without turning the car on, but I wouldn't have thought it would not bring on any warning lights. Even if it does, turn the ignition off, then on again and it should clear. I'm not at home at the moment, otherwise I would have had a play with my MAF and would have been able to give you a definitive answer as to if the warning light comes on on not. Is the car standard or tuned. My old A3 had uprated injectors, mapping and an uprated fuel pump, that killed the fuel economy.
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  14. monz87
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    monz87 Member

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    [Apr 29, 2012]
    My cars not tuned, as far as I am aware. I've only had it a week and it was suffering from terrible fuel economy but was pulling fast. Tnen eventually it lost mid range boost and I gave it back to the dealers I baught it from. I'm waiting to get it back from the dealers. I suspect it could be a common diverter valve problem. If MPG and boost is all sorted then I probably wont mess about with the MAF just incase I make things worse but then again after a while I may give it a shot as it is likely it would be even better after a clean.

    What is carb cleaner and where can I get it from? Is it the same as MAF cleaner and Isopropyl alcohol? Are they in halfords?
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  15. ben.w93
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    ben.w93 Member

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    [Apr 29, 2012]
    I can't remeber exactly, just some stuff I had left over from the Land Rover. MAF cleaner should do it, basicallly you want something that evaporates, I'm sure halfords will do something. You could always get the dealer to take a look for you if you are unhappy with the car.
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  16. raffhussain
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    raffhussain Member

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    [Apr 30, 2012]
    if your going to clean the MAF use electrical contact cleaner. does the job. used it on mine and it did the trick. if its a fault MAF, run car with it unplugged. should run better because the ECU wil start guessing fuel and air beacuse the MAF is unplugged. hope that helps
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  17. monz87
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    monz87 Member

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    [May 5, 2012]
    Right, I got my car back today, they replaced the crankcase breather valve or hose, can't remember which one though. The power is back :) Will monitor the fuel consumption and report back!
    #16
  18. monz87
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    monz87 Member

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    [May 18, 2012]
    Right, I want to clean my MAF, I baught some electrical contact cleaner from halfords. I posted on another forum, and so far it seems that I should be very careful about cleaning the MAF and apparantly I could make it worse? I don't have any warning lights, just poor fuel consumption, even after the crankcase breather valve or hose has been replaced.

    As some of you have done it already, what do you think??
    #17
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  19. Wrath
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    Wrath Well-Known Member

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    [May 18, 2012]
    Don't worry, just don't go sticking your finger in there or actually touching the metal bit which is on the inside. You will need some 5-star security torx (they are usually 6 star) otherwise you'll possibly ruin the screws removing them with pliers. A seller on Amazon have them available: Silverhill 5 Point Star Torx Bit Set (10 bits): Amazon.co.uk: DIY & Tools

    Remove the two screws, wiggle it slightly, pull it out and you should see the metal contacts through the hole at the bottom. I sprayed carb cleaner as it gets rid of oil and carbon better than contact cleaner. Put it back in. It's a 2 minute job.

    I don't suggest sticking cotton buds or anything into the gap.

    My car has increased it's mpg slightly but it's difficult to say it was the MAF cleaning that did it as temperatures have increased slightly which could have made the impact.
    #18
  20. viceroy
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    viceroy Member

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    [May 18, 2012]
    Hows your idle?
    My car was poor on fuel consumption, but power was fine, no error lights
    Also had no codes showing on VCDS, so mentioned it to the dealer at my last service, thinking it might be the multibox.
    Turned out to be the PCV, which I thought was strange because everything I've read about a PCV being faulty is that the idle jumps.

    What I had noticed, but very slightly is that when the car warm, the idle would suddenly just get ever so slightly lumpy...almost like the vibration you get when riding a clutch.

    So maybe check out the PCV...
    #19
  21. Wrath
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    Wrath Well-Known Member

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    [May 18, 2012]
    I've tried to find where and what the PCV valve is. Have you got any pics and does it need to be done by the dealer/indie?
    #20
  22. viceroy
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    viceroy Member

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    [May 18, 2012]
    Here ya go...all the help you should need
    link
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  23. Stringster
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    Stringster Missed gear

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    [May 18, 2012]
    Info on the PCV valve replacement here

    Easy enough to do yourself.
    #22
  24. Wrath
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    Wrath Well-Known Member

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    [May 18, 2012]
    Cheers Stringster, wasn't sure if it was the same for the TDI. Will have a bash when the weather gets better.
    #23
  25. monz87
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    monz87 Member

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    [May 18, 2012]
    My idle seems to be fine viceroy, is the pcv valve the same as a crankcase breather valve/hose. As this has been replaced on my one 2 weeks ago by Audi wen they put it on ther computers.

    Wrath, why did you clean your MAF? I'm worried that if there is nothing wrong with my MAF then I may make it worse!
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  26. Wrath
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    Wrath Well-Known Member

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    [May 18, 2012]
    Nah, you won't make it worse, trust me, don't worry. Just don't poke anything into it.
    #25
  27. monz87
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    monz87 Member

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    [May 18, 2012]
    Right I might give it a shot this Sunday, will keep you posted!
    #26
  28. johnnyfinlandia
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    johnnyfinlandia Member

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    [Nov 13, 2012]
    I have a 2006 1.8T Cab Auto and will be trying this as mine is doing just the same .. juddering on idle and a lot on full load when putting my foot down. Did you manage to remove and clean and seemed better afterwards? Also because it was Auto did you run without it or did you just take it out and clean and replace and try?

    Thanks, John.
    #27

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