Mas Air Flow Sensor
Results 1 to 8 of 8

This is a discussion on Mas Air Flow Sensor within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I suspect my MAS is going bad, checked the code and is either a MAS going bad or a vacuum ...

  1. #1
    Registered User
    Join Date
    Dec 2010
    Posts
    5

    Mas Air Flow Sensor

    I suspect my MAS is going bad, checked the code and is either a MAS going bad or a vacuum leak. I cleaned the MAS properly and the check engine light went away. After two days it is back on. Does the car need the MAS to run properly. I disconnected the electrical plug and it seemed to idle better and was very responsive. Any hints on how to isolate a vacuum leak?

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2
    Registered User
    Join Date
    Jan 2012
    Location
    Milwaukee
    Posts
    27
    How To Find A Vacuum Leak - EricTheCarGuy - YouTube

    But like the guy says there is a small chance it could ignite.

  4. #3
    UnBanned Sinister's Avatar
    Join Date
    Nov 2006
    Location
    Denver Metro Area
    Posts
    17,617
    I Support ClubWRX
    don't do that.

    A smoke machine is a better idea.

    What part of the country do you live in sonic?
    Kevin
    Moderator
    Sinister's Blowoff Valve FAQ
    WRX Gas Mileage FAQ
    Sinister's Progress Thread - 430whp 429wtq - Sold
    Firearms Enthusiasts Thread

    The Sheriff's Star at the bottom left corner rates a user's reputation.
    If you found a user's post to be helpful or quite the opposite, please make it known to them by clicking the Star!

  5. #4
    Registered N00b impretzel's Avatar
    Join Date
    Nov 2010
    Location
    SoCal 626
    Posts
    265
    I Support ClubWRX

    Mas Air Flow Sensor

    Quote Originally Posted by Sinister View Post
    A smoke machine is a better idea.
    ^this

    Do you have a volt meter? You test for a bad MAF by probing power and signal wires on the back of the plug and see if the volts are in spec. Maybe a more knowledgable member can help with the volt spec?

    But yes, the maf is required for optimal performance, fuel consumption, and cleaner emissions. Im surprised you got better results with it unplugged lol.
    '12 STi stage 2

    Origin GT = impretzel
    Bf4

    -JJ

  6. #5
    Admiral Ackbar mycologist's Avatar
    Join Date
    Oct 2005
    Location
    Late Devonian
    Posts
    12,771
    I Support ClubWRX
    Post the codes.

    Check all the clamps on the intake track especially between the MAF and the turbo. Make sure there are no tears in the inlet. Make sure all the return lines to the inlet ar attached and tight (I used zip ties). Make sure the intake box is fully and properly closed - those two tabs on the bottom have to be in good.

    Your MAF may be disagreeing with your front O2 sensor, and the O2 sensor may be the problem. The fact it got better with a cleaning is telling but I can't see how it would get re-fouled in a couple of days unless you are running some oily air filter.
    "From a little spark may burst a mighty flame." - Dante
    "The stitch is lost unless the thread is knotted." - Italian proverb

  7. #6
    Registered User
    Join Date
    Dec 2010
    Posts
    5
    I live in St. Louis. The smoke check is a great idea. I will also try all the other suggestions as well. It looks like there could be a little tear in the boot or hose connected to the turbo. I will have to disconnect the clamp to inspect.

  8. #7
    Registered User
    Join Date
    Dec 2010
    Posts
    5
    The code was P0171 I believe.

  9. #8
    He simply abides. SD_GR's Avatar
    Join Date
    Jul 2002
    Location
    CA, US
    Posts
    22,274
    I Support ClubWRX

    Mas Air Flow Sensor

    There are several PO171 threads; can't link you right now, sorry, but search. MAF, intake, etc.
    WRX Info Links, Courtesy TheJ
    The world breaks everyone and afterward many are strong in the broken places. Ernest Hemingway
    I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all... I think I can live with it. And if I had to do it all over again - I would. Benjamin Sisko
    DISCLAIMER: Opinions expressed are the author's alone and are inherently worthless.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •