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Thread: Lean AFR Problem

  1. #1
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    Default Lean AFR Problem

    Ok guys I need a little help. I missing something here that is causing the AFR to go lean @ 4000rpm with 30% throttle. My log shows that commanded is 13.84 and the WB02 is reading 15.15(frame 186). I made several logs to verify the lean condition and they all showed the same results. Lean @ 30 ~ 40% throttle. So I adjusted the TPS VE table to correct the lean condition and it made no difference. Still lean. Attached is the original tune and log. Thanks in advance for you input.

    Thanks
    Nick
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  2. #2
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    Attached is the tune with the adjustment to the TPS VE table and the log to go with it.

    Thanks
    Nick
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  3. #3
    EFILive Crew Site Admin Tordne's Avatar
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    One thing that might help people if they are going to try and help is to note which wideband is being used?

    The AD1 voltage is being logged but without knowing which wideband is used and potentially the scaling of voltage vs. AFR it might not be meaningful.
    Andrew
    EFILive Crew


  4. #4
    Joe (Moderator) joecar's Avatar
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    Hi Nick,

    You have the MAF DTC's (P0101,2,3) in C6001 set to not reported... this means the MAF is not failed (regardless of it being physically present or not)... so the PCM is using the MAF table... if the PCM doesn't throw a MAF DTC then it will still use the MAF.

    Set P0101,2,3 to A:1 Trip and verify that at least one of those DTC's triggers.

    Also, you have TPS VE table enabled upto 4400 rpm, 100 kPa MAP, 101% TP...
    i.e. so when the MAF fails the PCM will use the TPS VE table under 4400 rpm.


    Like Tordne said, which wideband are your using (what is it's calc pid)...?

    Also, remove GM.IAC and add GM.DYNAIR (g/s) for future non-idle logs.

  5. #5
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    I knew it was something simple. I did not realize that it would still use the MAF if it did not report the DTC. I unplugged the MAF and the car will not run more than 30 sec. Set the DTC back to Non Emissions with the MAF unplugged and all is well.I guess with the tune set to use the MAF table at 4000rpm it would cause an issue. Lesson learned. Thanks

    I am using an NGK wideband cal. PID attached. If there is anything else that stands out please let me know. I have spent a ton of time reading and trying stuff but we learn something new every day.

    Thankx again
    Nick
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  6. #6
    Joe (Moderator) joecar's Avatar
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    Check that you get a DTC...

    You may need to set A:1-Trip rather than Non-Emissions.

    Edit: altho Non-Emissions should work for setting the DTC.
    Last edited by joecar; July 14th, 2010 at 03:45 AM.

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