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MAF cause jerky part throttle

Discussion in 'A3/S3 Forum (8L Chassis)' started by anderswhk, Jun 13, 2013.

  1. anderswhk
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    anderswhk Member

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    [Jun 13, 2013]
    For some reason, whenever my MAF is plugged in, and i accelerate with like 1/3 throttle, it keeps dumping the boost every few seconds. It makes for an uncomfortable ride. It feels like the car stops accelerating completely for a brief second, again and again. Its enough to get you to move forward in your seat.

    When i unplug the MAF, everything is fine and smooth. What i dont get, is that the MAF has been running less than 10.000 miles, and the issue is only with part throttle. Wide open throttle there is no issues to speak of, so i am assuming its not a boost leak?

    Any ideas?
    #1
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  3. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 13, 2013]
    ONLY 10,000 MILES?!

    I have done three in half that time.

    Get a new one on there.
    #2
  4. anderswhk
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    anderswhk Member

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    [Jun 13, 2013]
    I thought those were suppose to be able to do atleast 3 times that.

    Its an AUM A3 btw.
    #3
  5. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 13, 2013]
    No, they aren't. What gave you that idea? Certainly no official documentation.

    Mines an AUM, running 245bhp and flowing over 190g/s of airflow; so my MAF gets a lot of work.

    Do a search, you will see that probably half of the daily fault related threads on this forum turn out to be the MAF.

    :)
    #4
  6. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [Jun 13, 2013]
    You've heard of rod lottery, along with dyno lottery,

    Now welcome to the MAF lottery!
    #5
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  7. anderswhk
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    anderswhk Member

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    [Jun 13, 2013]
    Okay fair enough im 25 under that, not sure about the airflow. Any better alternative to the OEM MAF?
    #6
  8. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 13, 2013]
    Nope, OEM MAF from VAG is the best option.

    Genuine Bosch from a VAG dealer, don't get a "genuine" Bosch from a parts dealer/motor factors. For some reason they aren't as good.
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  9. anderswhk
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    anderswhk Member

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    [Jun 13, 2013]
    Okay, thanks i will pick one up tomorrow, tho they are arounf 230 gbp, here atleast >_<
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  10. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 13, 2013]
    Lets hope I works then ;)

    I have had three in a row be faulty, ended up getting a refund and buying a second hand one and taking the risk. Touch wood it's been spot on for two months.
    #9
  11. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    Okay i have now been driving for a day with the new MAF, nothing has changed. It drives with no issues when the MAF isnt plugged in. What else could i look at? The obvious issue would be a leak somewhere, but when its full throttle, there is no problem.
    #10
  12. Gizmo20VT
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    Gizmo20VT Member

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    [Jun 18, 2013]
    Scanned for any error codes?
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  13. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 18, 2013]
    Reallllly.

    Is the car mapped? Have checked the wiring to the MAF connector for any splits or shortages?
    #12
  14. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    No error codes except for a cat error, because i have the Milltek one. Yes the car is mapped and has between 210 and 225 hp depending on the dyno. No splits or shortages. Could it be diverter valve related? I have the GFB one, that has an internal sleeve you can turn over for full recirculation, which i use.
    #13
  15. Gizmo20VT
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    Gizmo20VT Member

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    [Jun 18, 2013]
    Do you have a boost gauge installed?
    Also is your N249 still connected?
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  16. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    Yes, i have a boost gauge, i can see the boost dropping down to almost nothing when it does it. Its the exact same woosh sound as when you lift off the throttle. Can the E-gas engines go in and somehow regulate your throttle electronically?

    N249 still there. I was under the impression i wouldnt be able to go through MOT with it removed?
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  17. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 18, 2013]
    DV would be a good shout. That is a fairly large piece of information to have left out of your original post.

    And the N249 is just a boost control system, it won't effect your mot at all.
    #16
  18. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    What sort of consequences (if any) will it have if i do the delete?
    #17
  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    I wanted to post on this thread the other day and mention the DV but tapatalk was playing up.

    I have just been investigating some part throttle issues in my car and looked at my Forge 007P DV. I found a blue spring in it which is too strong for my application really and I also found excessive wear on one side of the piston. I've ordered up an OEM DV to see I this fixes my issues but I won't get time to test it just yet.
    #18
  20. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    I can adjust the firmness of the spring. Will give that a try.
    #19
  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    What DV have you got? Don't tell us you have a splitter R!...
    #20
  22. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    The N249 delete is only a good thing. Firstly it'll get rid of a load of hose that is likely to start perishing. Secondly it will speed up your throttle response, it's a great mod.
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  23. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    No i have an australian one named GFB Respons TMS. I bought it before i knew our engines werent fond of open blow off valves. It can be set to recirculate the air, which is how i use it.
    #22
  24. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 18, 2013]
    Could well be your valve then bud. Might be worth seeing if you can get hold of a tried and tested valve, either the stock valve or a 007P with a green or yellow spring.

    Other things to try would be to make the sprin in your current valve a lot weaker and also open it up and check the piston is ok (if possible). Might need to service the DV seals or grease up the piston.

    I also highly recommend the N249 delete too as this could still be your issue and it's an easy mod for the price of a length of silicone hose.
    #23
  25. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [Jun 18, 2013]
    So one of these....

    GFB Respons

    Can't say I have heard of them, but loos very similar, works in the same way and priced almost identically as the Forge Split R - I'd get rid asap tbh and try a full recirculating valve.

    You got any VAG buddies with the 1.8t DV? Could ask to borrow there's quickly to see if that fixes the problem.
    #24
  26. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    Yeah, its that one kwistof. I have been thinking about getting a Forge for a while. Which one would be the best of these, not counting the splitter? Forge Motorsport | Alloy Fabrication
    #25
  27. kwistof
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    kwistof South East Events Moderator Regional Rep

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    [Jun 18, 2013]
    Can of worms that question dude! lol

    Jardo created a huge thread on DV's and it's in the stickies. Either the 007P or the 008P with the revised piston is the best from Forge IMO....however as Bill and Jardo proved- the OEM dump valve can hold 30psi safely and is less likely to fail...plus it's a lot cheaper....but doesn't have any 'bling' factor :) lol
    #26
  28. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    I got the engine cover on, bling factor means nothing :p
    #27
  29. Tim_Attard
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    Tim_Attard Active Member

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    [Jun 18, 2013]
    get rid of the DV put the stock one back on if you still have it or get one from ebay for cheap, this way you can make sure its the dv before getting a good one (007) also do the n249 delete as its a great mod for very little money and time
    #28
  30. anderswhk
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    anderswhk Member

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    [Jun 18, 2013]
    Right, trying the N249 bypass, hopefully getting it done before the weekend.
    #29
  31. anderswhk
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    anderswhk Member

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    [Jun 21, 2013]
    N249 done, no change. The sound of my divertervalve dumping boost has changed for some reason.

    Didnt remove the whole system.

    Something im forgetting, exept for clamps? :p

    boost.jpg
    #30
  32. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 21, 2013]
    None of mine are clamped.

    Looks fine to me.
    #31
  33. Westy
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    Westy Double Dark Side! Diesel & 8P

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    [Jun 21, 2013]
    Time to change that DV then ;)
    #32
  34. Gops
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    Gops 6th gear @7000rpm

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    [Jun 21, 2013]
    I had this and it was my maf plug was loose. Replaced that (only £3) and worked fine :)
    #33
  35. anderswhk
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    anderswhk Member

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    [Jun 21, 2013]
    I guess next step is an 007p

    Had an Audi dealer computer hooked up to it. Shows loss of boost pressure.

    None of this explains why the car runs fine with the MAF off?
    #34
  36. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 21, 2013]
    No 007p.

    Stock OE or go home :)
    #35
  37. anderswhk
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    anderswhk Member

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    [Jun 21, 2013]
    I always heard the stock DVs were rubbish, and couldnt even handle a car with just a map.
    #36
  38. Gops
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    Gops 6th gear @7000rpm

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    [Jun 21, 2013]
    Have you checked your connector?
    #37
  39. anderswhk
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    anderswhk Member

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    [Jun 21, 2013]
    Plugs seems to work fine.
    #38
  40. Gops
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    Gops 6th gear @7000rpm

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    [Jun 21, 2013]
    Pop it on vcds, check you maf log on idle, then wiggle the maf connector, If the values dip then the connector is loose.
    #39
  41. 16Klappe
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    16Klappe Princess Clap.

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    [Jun 21, 2013]
    Well you heard wrong. And whoever told you that deserves to be shot.

    Stock OE valves can hold far more boost than your turbo could ever make, and respond quicker than most valves as well as cost peanuts.
    #40
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