1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome To LandyZone!

    LandyZone is the biggest Land Rover forum on the net. We have plenty of very knowledgable members so if you have any questions about your Land Rover or just want to connect with other Landy owners, you're in the right place.

    Registering is free and easy just click here, we hope to see you on the forums soon!

P38 4.6 Petrol: Mass Airflow meter. What symptoms?

Discussion in 'Range Rover' started by Mud Flap, Apr 6, 2008.

  1. Mud Flap

    Mud Flap New Member

    Joined:
    Sep 8, 2007
    Posts:
    217
    Likes Received:
    0
    Location:
    Coventry
    1998 P38 4.6 Petrol only
    -----------------------

    What symptoms do you get if your mass airflow meter is faulty?

    Car drives great normally but put your foot down to overtake and you get a sudden loss of power for about half a second. It picks up afterwards and you can really feel the acceleration.

    Does it sound like the engine is temporarily starved of air?
     
  2. Mud Flap

    Mud Flap New Member

    Joined:
    Sep 8, 2007
    Posts:
    217
    Likes Received:
    0
    Location:
    Coventry
    I guess no one knows then :(
     
  3. Hackett

    Hackett New Member

    Joined:
    Apr 5, 2008
    Posts:
    74
    Likes Received:
    0
    Sometimes you get lumpy idle when the maf fails. Best way to diagnose is to disconnect the maf and the ECU will use a default fueling setting, if it runs ok with maf disconnected then you know it was your maf at fault.

    This has worked on a couple of my mates cars at work after they have spent 100's on garage diagnostics with no faults found.
     
  4. 47p2

    47p2 New Member

    Joined:
    Feb 7, 2008
    Posts:
    86
    Likes Received:
    0
    Location:
    Between there and there
    MAF does not show up as a fault on garage diagnostics.
    Easiest way to diagnose it is if you can get hold of a good MAF and swap the part over.
     
  5. Mud Flap

    Mud Flap New Member

    Joined:
    Sep 8, 2007
    Posts:
    217
    Likes Received:
    0
    Location:
    Coventry
    Thanks both.


    My idle is a little lumpy but only just noticeable.

    I will try a run with it disconnected and see what happens.
     
  6. Mud Flap

    Mud Flap New Member

    Joined:
    Sep 8, 2007
    Posts:
    217
    Likes Received:
    0
    Location:
    Coventry
    I just tried it with it disconnected and the idle got a lot more lumpy. It would not start with it off. When I put my foot down there was no acceleration at all and a GEARBOX FAULT message came up.

    I stopped and reconnected it and all was well again. I couldn't actually reproduce the sudden power loss. Strange.
     
  7. Hackett

    Hackett New Member

    Joined:
    Apr 5, 2008
    Posts:
    74
    Likes Received:
    0
    well i'd say the maf is fine then
     
  8. david451

    david451 New Member

    Joined:
    Aug 1, 2007
    Posts:
    1,955
    Likes Received:
    0
    Location:
    scotland
    My son had an air flow meter fault and yes the chaps right it didn't show up on the diagnos. Would be ok then sudden loss of power and you can't drive through it, the more throttle you give to overcome the loss the worse it was. It started off as an occasional slight loss for a second or two and went to total menace.

    We had it on several diagnos and everybody had a different theory, if you can get a friend to let you borrow his air flow, go for it, if it does it constant then, use his as spares until you get it. That's what I had to do, the parts are just too expensive for trial and error. At one point I was going to hire one and take the bits off it, I was so ****ed off.
     
  9. Mud Flap

    Mud Flap New Member

    Joined:
    Sep 8, 2007
    Posts:
    217
    Likes Received:
    0
    Location:
    Coventry
    Mine is never like that. Once it's through the dead spot it's off like a bat out of hell. Maybe I am expecting too much from a 2.5 tonne beast.
     
  10. david451

    david451 New Member

    Joined:
    Aug 1, 2007
    Posts:
    1,955
    Likes Received:
    0
    Location:
    scotland
    wif a 4-6 enjun!!!, my work had one an it felt like it had no body, but drank fuel like a lizard drinkin water.

    As I said ours started off like that then got worse, perhaps best waiting til it gets worse, you should know what is norm and whats not.