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Thread: Fuel trims pulling 100% fuel, but O2 reads lean

  1. #1
    Tuner in Training
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    Fuel trims pulling 100% fuel, but O2 reads lean

    Anybody know why my STFT and LTFT are pulling 100% fuel while the O2 sensors are mostly reading absolute minimum (~60mv). To preface this is an E67 from and 08 atlas 4200, on a completely different engine (2.8L Nissan L28).
    I'm using a manual transmission, the stock MAF with a 2.5" feed before it (factory was 3"). I expect the numbers to be quite off, but it seems the fuel trims are doing the exact opposite of what the engine wants.
    Last edited by rindoze; 11-11-2023 at 08:56 AM.

  2. #2
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    Here is the log. This is taken while in neutral, revving the engine. latest.hpl

  3. #3
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    NVM looks like I was being mislead by the default log layout. It is mixing in the non existent bank 2 sensor into the readings and thus throwing them off.

  4. #4
    Senior Tuner edcmat-l1's Avatar
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    Quote Originally Posted by rindoze View Post
    NVM looks like I was being mislead by the default log layout. It is mixing in the non existent bank 2 sensor into the readings and thus throwing them off.
    No, if the bank 2 sensor was non existent it would read roughly 445ish mv. That's the disconnected or open circuit value. A value of dead zero is the harness burned to the header LOL. Seriously that's a grounded circuit.

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