Air fuel ratio really rich (2018 Mustang gt)

Discussion in 'V8 5.0L Engine / Mods: Bolt-ons, Exhaust, Tuning' started by maxcraig00, Oct 11, 2019.

  1. maxcraig00

    maxcraig00 Member

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    Hey guys quick question.(2018 mustang Gt JLT CAI, E85 tune). I have been getting code p0003 on my lund tuner. It says heater control circuit. My air fuel ratio is super rich. 8.5-9.8 on idle and doesnt change on WOT. Sometimes it jumps to 10.5. I am currently on E85 and it been on E85 for the past 6 months. I tried cleaning my MAF sensor. I dont know what the problem is. But it seems I am running to rich.
     
  2. blackyote_317

    blackyote_317 Well-Known Member

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    I'm not on e85 but I'm pretty sure that's exactly where your AFR should be...I don't think that has anything to do with your code.
     
  3. SheepDog

    SheepDog Well-Known Member

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    Your AFR is about right for E85. Just depends on the actual alcohol content. Perfect Stoichiometric ratio for E85 is 9.8:1
     
  4. SheepDog

    SheepDog Well-Known Member

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    Also, code P0003 is a generic OBD2 code for Fuel Volume Regulator Control Circuit Low. It has to to with your high pressure direct injection system. Check the fuel rail pressure sensor, connector and wiring
     
  5. 3star2nr

    3star2nr Well-Known Member

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    Check for vacuum leaks down stream of the mass sensor.
    Check for bad o2 sensor.
    Contact lund, send data log
     
  6. EFI

    EFI Well-Known Member

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    Your AFR is right, E85 requires quite a different ratio than E10.
     
  7. SheepDog

    SheepDog Well-Known Member

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    Vacuum leaks cause a lean condition, not a rich condition.
     
  8. EFI

    EFI Well-Known Member

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    Which none of those are present in the OP's post, so not sure why he's having him go on a wild goose chase for a phantom problem.
     
  9. SheepDog

    SheepDog Well-Known Member

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    Truth. The moral of this story is that there is no problem. OP's AFR is correct for E85.
     
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