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Thread: STFT BANK 1 AND STFT 2 ARE 10% OFF. What could be the cause

  1. #1
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    STFT BANK 1 AND STFT 2 ARE 10% OFF. What could be the cause

    2018 zl1 with ported blower/snout , TSP cam, 2.3 upper, 5" intake, 103 TB, and 2" header back 3" exhaust, MM Catch Can, Low side pump, running 93.

    I'm lost and running out of troubleshooting options. According to my VCM Scanner logs, my STFT 1/2 are 10% apart. seems like I have a vacuum leak of some sort on my bank one.. I've done a leak test by spraying break cleaning along the base of the blower, valve cover, catch can tubes, exhaust manifolds, and pvc lines. I've also cleaned my O2 and wideband sensors, I have 0 leaks coming from my exhaust.





    Idletest9.hpl

  2. #2
    Tuner in Training
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    Maybe just an aging front sensor. I've never heard of cleaning an AFR sensor - don't think that's a good idea. If you don't have any leaks in the exhaust system around the sensors and you checked for intake leaks that could cause a bias, then not sure there's much else to do. You could try swapping bank 1 and 2 sensors to see if the problem follows it but that's a lot work. GL

  3. #3
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    Hmmm i doubt its aged. Its 3 months old.

    I will swap them to see if the problem follows.

  4. #4
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    What size and brand injectors?

  5. #5
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    Stock

  6. #6
    Advanced Tuner
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    I've seen the teflon seals around the injectors leak and cause this. It's a vac leak that the brake cleaner can't get to sometimes.

  7. #7
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    Can you post the calibration file?

    What brand headers?

  8. #8
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    Quote Originally Posted by sevinn View Post
    I've seen the teflon seals around the injectors leak and cause this. It's a vac leak that the brake cleaner can't get to sometimes.
    He is right. I would smoke test the intake and the exhaust before ruling out any vacuum or exhaust leaks.

  9. #9
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    I had this problem after I installed my cam and heads myself. (first time ever tackling a job this big)

    I pulled the injectors out of the heads. Instead of just leaving them in the heads. I didn't get the new seals on properly and I caused exactly what you have. I have a good video saved on how to redo the seals without using any speacial tools. If you want to see it?

  10. #10
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    id like to see that video

  11. #11
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    Quote Originally Posted by Jonblarc7 View Post
    I had this problem after I installed my cam and heads myself. (first time ever tackling a job this big)

    I pulled the injectors out of the heads. Instead of just leaving them in the heads. I didn't get the new seals on properly and I caused exactly what you have. I have a good video saved on how to redo the seals without using any speacial tools. If you want to see it?
    id like to see that video

  12. #12
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    Quote Originally Posted by Jonblarc7 View Post
    I had this problem after I installed my cam and heads myself. (first time ever tackling a job this big)

    I pulled the injectors out of the heads. Instead of just leaving them in the heads. I didn't get the new seals on properly and I caused exactly what you have. I have a good video saved on how to redo the seals without using any speacial tools. If you want to see it?
    I'd like to see the video too please