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Thread: LS1b semi-closed loop operation question (B3647)

  1. #1
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    Default LS1b semi-closed loop operation question (B3647)

    EFILive has the LS1b has the B3647 Commanded Fuel/RPM,which when set to 14.63, will cause the ECU to go into a semi-closed loop state using the O2 sensors to keep idle and part throttle AFR @ 14.63.

    If I want my idle and part throttle set to 14.1, then my O2 sensors will be ignored. How does the ECU command the AFR when in this state since the O2s are ignored? By the VE table?

    Question: Is there a way to set B3647 to something like 14.1 and still have the O2 sensors ACTIVE?

  2. #2
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    Quote Originally Posted by RamAir View Post
    EFILive has the LS1b has the B3647 Commanded Fuel/RPM,which when set to 14.63, will cause the ECU to go into a semi-closed loop state using the O2 sensors to keep idle and part throttle AFR @ 14.63.

    If I want my idle and part throttle set to 14.1, then my O2 sensors will be ignored. How does the ECU command the AFR when in this state since the O2s are ignored? By the VE table? Yes, that is correct

    Question: Is there a way to set B3647 to something like 14.1 and still have the O2 sensors ACTIVE? No, even if you could then the O2 sensors would fight the 14.1 and move it back to stoich
    Rgds

    Jim
    2000 LS1 M6, No EGR/Air/PS/CATs. TR230 Cam, COS3, OLSD, LC1 Wideband fitted, Procharger P1SC, 2 Bar MAP, Siemans Dekka 60Lb Injectors.
    All wrapped up in a 2000Lb AC Cobra Replica

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    Ok - another question: why would you want to SFTF Idle Disable (B4108)? Don't you want SFTF since the O2s are giving feedback?

  4. #4
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by RamAir View Post
    Ok - another question: why would you want to SFTF Idle Disable (B4108)? Don't you want SFTF since the O2s are giving feedback?
    Yes, you do want.

  5. #5
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    That is what I thought, but in your documentation (pg 17 of COS using 2/3 bar) it indicates "several other STFT values may require adjustment:" {B4108} STFT Idle Disable. This value would either be on or off and your above statement indicates it should be on indicating I should not adjust. Confusing documentation.

  6. #6
    Joe (Moderator) joecar's Avatar
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    You should try it both ways, just to see.

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