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LS1 Idle Fuel Issues

Understanding AFR

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Discussion and questions related to the course Understanding AFR

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Hey all! Tuning a Procharged LS1 and having some weird issues. I failed the MAF and tuned SD with SD AFR Error table to begin with and got idle pretty decent. Enabled MAF with MAF AFR Error table and it looks really good. Im having issues with the car randomly stalling. On both error tables, Im less than 1% fuel change. My fuels trims are WAAAY off. Why is there so much discrepancy between them??

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The issue is that to do what you're trying to do, you need to force the ECU into open loop. Right now your actual AFR error might be close to zero, but that's because your STFT + LTFT are picking up the pieces and fixing the error that's actually there. You can either force open loop and rely on the AFR error calculated from your wideband/Commanded AFR (preferred and the only option in PE), or alternatively in closed loop you can use the STFT + LTFT math channel to fill in your histogram (again, this is only useful in closed loop mode).

This is all covered in detail within the Practical Reflash Tuning course's worked examples if you haven't got that course. You may also need to make some changes to your base running airflow tables if you're still having stalling issues. Check out this webinar - https://www.hpacademy.com/previous-webinars/217-idle-tuning-hp-tuners-gmhp-tuners/

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