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MAF reading 3.4g on my 2.7

Discussion in '1st Gen. Tacomas (1995-2004)' started by Rachelsdaddy, Feb 29, 2020.

  1. Feb 29, 2020 at 4:47 AM
    #1
    Rachelsdaddy

    Rachelsdaddy [OP] Well-Known Member

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    Does anyone know why on earth my MAF is reading 3.4g at idle? As far as I know they should match the engine displacement. Can anyone verify this? Thanks!
     
    Black DOG Lila likes this.
  2. Feb 29, 2020 at 4:52 AM
    #2
    Blais03

    Blais03 Guess I'll bring a spare wheel bearing...

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    What year?
     
  3. Feb 29, 2020 at 5:17 AM
    #3
    Clearwater Bill

    Clearwater Bill Sometimes when I close my eyes, I can't see.

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    Check his profile, says 99.

    Although I'm not sure what a pre runner 4x4 is. Conversion?
     
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  4. Feb 29, 2020 at 7:12 AM
    #4
    Rachelsdaddy

    Rachelsdaddy [OP] Well-Known Member

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    Yeah, it’s a 99 2.7 PreRunner. I have been chasing drive ability issues for years. High +10 ltft. If I am correct and this should read 2.7 grams per second either I have the improper maf (from a 3.4) or the ecu is incorrect for the truck. If the ecu thinks it’s getting 3.4 g of air seems to me it would certainly be trying to add fuel. The maf that’s in there supposedly came from a 2.7, bought it from a boneyard online. Any techies know for sure?
     
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  5. Feb 29, 2020 at 7:29 AM
    #5
    Black DOG Lila

    Black DOG Lila Well-Known Member

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    Stock. EZ pass.Dump pass.Inspection sticker.Convict printed lic.plates.FG cap.
    I'd start by changing that sock you've been using for a gas cap and the burned out CEL lightbulb.
    That S2 O2 diode under passenger seat isn't helping driveability either.
    Clean the MAF with a stiff wire brush and Drano liquid if you're feeling adventureous.:bananadead:
     
    Wyoming09 likes this.
  6. Feb 29, 2020 at 7:41 AM
    #6
    vasinvictor

    vasinvictor Junkie

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    Replace upstream o2 with new Denso unit of the correct variety. 99 should be 234-4161 or 234-4162, and inspect your intake boot for cracks creating vacuum leaks. Have you injectors cleaned- mabye they a bit clogged, forcing ECU to "add fuel" to compensate. +10 aint terrible though. That's the beauty of fuel injection.
     
  7. Feb 29, 2020 at 7:49 AM
    #7
    Glamisman

    Glamisman Well-Known Member

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    I understand your thinking... Spitballing and thinking out loud here, if there was a slight vacuum leak the O2 sensor would compensate but the g/sec would be lower... is the idle normalish, not over 800 rpm? The 4 cylinders seemed to be different throughout the years... some have a MAP sensor some dont. The brake vacuum booster is often overlooked for vacuum leaks... squeeze the hose and look at STFT for an improvement. Raise the rpms slowly and hold at say 2k and look at STFT... if it improves toward 0 then there is definitly false air somewhere. What does the IAT show... this is built into the MAF as far as I know. PCV valve OK?
     
  8. Feb 29, 2020 at 8:46 AM
    #8
    Rachelsdaddy

    Rachelsdaddy [OP] Well-Known Member

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    Can you guys re-read the original post? I know my O2 is correct. I’d like to know how many grams per second is a 2.7 supposed to read at idle. I’m fairly sure it should be 2.7. This is where I’d like to concentrate. My scanner is reading 3.4. Lol. If it’s a nice day where you live, have a 99, a 2.7, scanner and a couple minutes to help me out please see what your maf is reading. I will send you a Dunkin’ card. Thanks
     
  9. Feb 29, 2020 at 8:48 AM
    #9
    Rachelsdaddy

    Rachelsdaddy [OP] Well-Known Member

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    Mine doesn’t whistle when going down the road , or did you put some FlexTape over the hole already... lol, smaht ass
     
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  10. Feb 29, 2020 at 9:05 AM
    #10
    Black DOG Lila

    Black DOG Lila Well-Known Member

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    Stock. EZ pass.Dump pass.Inspection sticker.Convict printed lic.plates.FG cap.
    It's on my to do list for the wet carpet fix:thumbsup: Rubber floormat on passenger side delete mod for now keeps it dry till I can find a screwdriver:D
    I just turn up the radio for Taco whistle drown out mod:rofl::rofl:
     
    Rachelsdaddy [OP] likes this.
  11. Feb 29, 2020 at 9:11 AM
    #11
    Black DOG Lila

    Black DOG Lila Well-Known Member

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    Do you think the whistle and drip are related? Would be nice to fix both with flex tape once I find a screwdriver.
     
    Rachelsdaddy [OP] likes this.
  12. Feb 29, 2020 at 9:17 AM
    #12
    Black DOG Lila

    Black DOG Lila Well-Known Member

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    Stock. EZ pass.Dump pass.Inspection sticker.Convict printed lic.plates.FG cap.
    Make it a case of BJs and I'll bring full diagnostics immediately:thumbsup:
    Can't eat donuts got Sugarbeadies. Sickashellnemia and HPV2
     
  13. Feb 29, 2020 at 9:28 AM
    #13
    Reh5108

    Reh5108 Well-Known Member

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    I read mine in cfm..I think. I don't think it's going to match the liter of the engine.
     
  14. Feb 29, 2020 at 9:31 AM
    #14
    Speedytech7

    Speedytech7 Toyota Cult Ombudsman

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    I've done a mod or two
    Mine read somewhere from 3.3-3.6 at idle. It's fine
     
  15. Feb 29, 2020 at 9:54 AM
    #15
    Rachelsdaddy

    Rachelsdaddy [OP] Well-Known Member

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    Bummer. Thanks
     
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  16. Feb 29, 2020 at 10:09 AM
    #16
    Wyoming09

    Wyoming09 Well-Known Member

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    I am curious how a mass and weight label is used to measure volume Looking to learn something new !!
     
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  17. Feb 29, 2020 at 6:15 PM
    #17
    Glamisman

    Glamisman Well-Known Member

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    the "perfect" ratio of air to fuel is apx 14.7 to 1. So many grams of air per second equals so much weight then the PCM calculates fuel based on that, modified by air temp, throttle position etc.etc.
     

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