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MAF readings?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Les 51, Aug 12, 2007.

  1. Les 51
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    Les 51 A pint of Diesel please!

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    [Aug 12, 2007]
    Hi Guys,
    Need some help please. I plugged my A4 into VAGCOM today to check out some info I was told by the garage that serviced my car.
    It came back with no faults (thank god!), but the MAF readings were changing wildly between 130mg/str to 320 mg/str.
    Is this ok ? the Specified readings are supposed to be 170mg/str to 180mg/str.
    I assuming the MAF sensor has gone wrong and needs to be replaced, but not being very knowledgable about cars I'm not sure .
    Any help gratefully received
    Thanks

    Les
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  3. icenutter
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    icenutter Member

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    [Aug 12, 2007]
    What you need to to is log actual and specified MAF for a full throttle run in 3rd gear. Then plot a graph of mg/str vs. rpm. The rule of thumb is 0.8*mg=power. If actual and specified are wildly different, and/or max values are low then the MAF sensor is probably gone.

    My actual and specified MAF values were 5% out and a change of sensor made a small but appreciable difference.

    While you are doing this you might as well log and plot actual and specified MAP (mass inlet pressure).
    #2
  4. Elberoth
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    Elberoth Member

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    [Aug 13, 2007]
    When your MAF is gonna say good bye, you can see that in the Block 032. Both values should be close to 0. Out of spec values, like + or - 15% may indicate faulty MAF.
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