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think maf's knackered...how to test?

Discussion in 'A3/S3 Forum (8L Chassis)' started by scott13, Feb 7, 2011.

  1. scott13
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    scott13 Member

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    as above guys, was getting a fault code and thought i had a split hose, got them checked and nothing found. anyway guy suggested that its a new maf required but before i buy one i was wondering is it right that if you unplug maf and engine stays the same then its ok? cause i tried this and it almost cut out so does this mean its knackered?

    cheers
    Scott
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  2. Essflee
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    Essflee Active Member

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    If engine improves with maf disconnected then the maf is knackered, strange that your car seemed to almost cut out when disconnected, shouldn't do that...
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  3. scott13
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    scott13 Member

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    what should it do then?
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  4. Essflee
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    Essflee Active Member

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    When you disconnect the maf your esp light will come on iirc, but the car should still run ok because the ecu will then run off default settings, if your car is mapped with a decent maf, when disconnected the car wont pull as well, but certainly wont cut out...

    What fault code were you getting do you know ?
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  5. scott13
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    scott13 Member

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    this was the code :- 17536/P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean

    just took car for a run and it cut ran ok but cut out when i stopped.

    and the light didnt come on which was strange?
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  6. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Cutting out and a fuel error could point to the fuel regulator hose or maybe a weak fuel pump. You really need to get it logged on VCDS mate.
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  7. scott13
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    scott13 Member

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    i have vag come but dont know how to log things?
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  8. Essflee
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    Essflee Active Member

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    Could check the boost pipes under the inlet mani for leaks and see if everything looks ok,
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  9. scott13
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    scott13 Member

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    dont have a turbo mate..would i still have boost pipes?
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  10. Essflee
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    Essflee Active Member

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    Negative...lol
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  11. scott13
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    scott13 Member

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    didnt think so lol
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  12. Essflee
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    Essflee Active Member

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    There's a sticky at top of page that may help you.
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  13. scott13
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    scott13 Member

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    cheers
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  14. scott13
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    scott13 Member

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    done as the sticky says and both sides stayed at 0% am i doing this wrong?
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  15. Westy
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    Westy Double Dark Side! Diesel & 8P

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    What were you logging Scott?
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  16. scott13
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    scott13 Member

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    Block 032 mate
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  17. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Log block 002 and that will tell you what the MAF is doing. Whatever g/s you are getting we can then convert that to BHP to see if the MAF is reading correctly.
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  18. scott13
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    scott13 Member

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    Ok will do that tommorrow mate, do i drive car or leave it idleing?
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  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Sorry I should have said. Ideally you want to take the car close to the red line for a few gears as this will log the maximum air flow. Whenever I do any of my logging I stick the car in 4th at around 2K revs and then floor it and take it to the red line but I have an S3 and this is normally the best way to get a steady boost reading.
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  20. scott13
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    80.36 g/s was the highest reading i got at about 6500rpms . does this mean maf is ****?
    Last edited: Feb 8, 2011
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  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    What car have you got? 80.36 g/s is about 100bhp
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  22. scott13
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    scott13 Member

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    2001 1.8 non turbo
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  23. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Well the book power for a non Turbo 1.8 is 123bhp so you're not far off.

    What was your g/s reading when idle? If its between 2-4 then your maf might be ok. If the reading is less than 2 or more than 4 at idle, i'd say you need a new MAF.
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  24. scott13
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    scott13 Member

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    will check it out and get back to you
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  25. scott13
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    reading was 2.8 g/s on idle..is it ok then?
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  26. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Yeah that sounds ok. Have you tried driving the car with the MAF disconnected? Does it feel smoother, more responsive, faster?
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  27. scott13
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    scott13 Member

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    yeah mate tried that first but it would run ok but cut out when i stopped, at first when unplugged it almost cut out too
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  28. audi-tk
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    audi-tk Member

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    Where would I unplug the maf on 1998 1.6 peeps? Thanks
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  29. DenCar
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    DenCar Member

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    The MAF comes off your Air-Filter Housing and has an electrical socket on it, just disconnect the plug.

    DC
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