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Thread: Boost leak MAF Reading

  1. #1
    Junior Member
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    Default Boost leak MAF Reading

    I am having a problem with my afr on my truck. I swapped my maf and my bov so that the MAF would be after the bov on the charge pipe. The truck ran great the oppisite way but after a wot run it would stumble because of the air being let off the charge pipe after the maf read the info. So I changed them around sunday and got in the truck to drive it and my afr is the same at cruise but under boost the afr drops to a steady 10.9 and at wot in the 9's. Now keep in mind the tune has not been changed from when it ran great before. What do i need to look for.....my maf is reading 1.42g/cycl and the engine is only seeing 1.12 at tops.
    The maf is connected to the tb so the air that it sees is definately going into the intake just not reading it correctly. Any help would be appriciated. Oh and how can i post my tune for you guys to see?

  2. #2
    Lifetime Member hquick's Avatar
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    Default

    You want the AFR's to drop like that....but that's probably a bit too rich.
    I believe you'll need to re-scale the MAF.
    Do a search for 'AutoMAF'.
    To post your tune and a log....scroll down to the 'Advanced' tab when typing a post.
    Click on 'manage attachments' and attach your tune/log.
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

  3. #3
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    yea it has all been set up for that previously but when i moved it is when i saw the afr get way too rich. Also the g/cyl are higher than normal! Not sure if it might be a bad maf?

  4. #4
    Lifetime Member hquick's Avatar
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    Anytime you alter the air intake setup...you need to rescale the MAF.
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

  5. #5
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    this is way out of my league. Justin at bbp did my tune and is awesome but he just mentioned that i have a leak or a bad maf due to the g/cyl being higher than normal. He has done my tunes before and ran great but as far a altering the intake set up it is a different of about 3" on the charge pipe. just enough to get after the bov. The problem is the maf is seeing the air and the manifold is not? What could cause that? trash on the maf or leak or a bad maf?

  6. #6
    Lifetime Member hquick's Avatar
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    Well...you could try cleaning the MAF with some electrical contact cleaner (non-residual type).
    Don't touch the wires...just spray them clean.
    ANY alterations to the intake tube will make a difference to the airflow and require adjustment of the MAF curve.
    Justin is a great guy and a friend. I'm sure he can sort things out for you.
    Do you have EFILive for yourself?
    If cleaning the MAF doesn't help...you could try changing it. I've picked them up on Ebay before for as little as $1.
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

  7. #7
    Lifetime Member hquick's Avatar
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    Oh...what vehicle is it?
    The LS1 type Aluminium MAF's are VERY susceptable to heat. Being on the charge side...I imagine it will be getting alot hotter than it was before.
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

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