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Thread: ecm is commanding 1.09 lambda...but I cannot find where its coming from..

  1. #1
    Senior Tuner S2H's Avatar
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    ecm is commanding 1.09 lambda...but I cannot find where its coming from..

    I have looked at the file in both SCT and HPT....
    when cruising down the road at low throttle the ECM is commanding lambda 1.09+ sometimes....

    I cannot find the table or the multiplier where it could be coming from...
    Fuel Base/Fuel base Cold are all 1.0 or richer...


    sorry I dont have the file in front of me.. I can get it tomorrow if needed.
    -Scott -

  2. #2
    what kind of vehicle?

  3. #3
    Senior Tuner S2H's Avatar
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    2007 Ford Mustang GT500
    -Scott -

  4. #4
    what value are you using to determine commanded lambda? exactly 1.09 or does it fluctuate?

  5. #5
    Senior Tuner S2H's Avatar
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    I'm watching "commanded B1 lambda"...it commands 1.09

    it fluctuates some...but its roughly 1.09
    when I get onto the gas more, it goes back to commanding what I have in the Base fuel tables

    my issue is that I dont know where the commanded value is coming from when it commands 1.09 ish.
    -Scott -

  6. #6
    HPT Employee Eric@HPTuners's Avatar
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    Do you have it forced into open loop?
    Eric Brooks
    HP Tuners, LLC

  7. #7
    Senior Tuner S2H's Avatar
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    no, its in closed loop
    fuel system status says so in the scanner
    -Scott -

  8. #8
    HPT Employee Eric@HPTuners's Avatar
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    What do the fuel trim values show? I haven't tested what our scanner shows for some of these parameters.
    Eric Brooks
    HP Tuners, LLC

  9. #9
    Senior Tuner S2H's Avatar
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    fuel trims and a wideband follow the commanded lambda to the 1.09 ish values
    -Scott -

  10. #10
    HPT Employee Eric@HPTuners's Avatar
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    We gotta get our scanner update out! I suspect the commanded lambda value you are seeing is just a fuel correction value. I would adjust to get the fuel trims in order and disregard that pid. When it is in closed loop, it targets stoich, period.
    Eric Brooks
    HP Tuners, LLC

  11. #11
    Senior Tuner S2H's Avatar
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    it follows the Base Fuel commanded perfect...except for a spot during part throttle low load, low throttle...cruising down the road...
    -Scott -

  12. #12
    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by S2H View Post
    it follows the Base Fuel commanded perfect...except for a spot during part throttle low load, low throttle...cruising down the road...
    It doesn't use that table except in open loop.
    Eric Brooks
    HP Tuners, LLC

  13. #13
    Senior Tuner S2H's Avatar
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    you are right... I just found the table I edited with TPS to go back to open loop...


    either way...its commanding 1.09 at part throttle while crusing low tps..., and I have no idea where its coming from
    and when it crosses to open loop, it commands the values in the open loop tables.

    it does command 1.0 lambda most of the time in closed loop.
    -Scott -

  14. #14
    HPT Employee Eric@HPTuners's Avatar
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    Can you post or email me a log to look at and the tune file in question?
    Eric Brooks
    HP Tuners, LLC

  15. #15
    Senior Tuner S2H's Avatar
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    I dont usually save logs...but I'll see if the one I did save has it happening in it...
    might be able to go for a drive next week...
    weather is supposed to be nasty down here for the next few days.
    -Scott -

  16. #16
    Senior Tuner S2H's Avatar
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    here you go..
    Attached Files Attached Files
    -Scott -

  17. #17
    Senior Tuner S2H's Avatar
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    ok...
    went out today in the car....
    trying to complete it so we can get it back to the customer....
    cant figure out what I am missing...
    vehicle commands leaner than stoic multiple times, multiple places....including WOT?
    no idea where its coming from....
    heres the tune, and a Log

    sorry, no TPS sensor logged... Just look for the Load values to go up for WOT...
    Attached Files Attached Files
    -Scott -

  18. #18
    HPT Employee Eric@HPTuners's Avatar
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    After looking over this, it is exactly as I suspected. The value you are looking at is really just the short term fuel trim. On a Ford, in open loop, the value that the STFT shows is the commanded lambda value. When it is in closed loop, it is the amount of correction being made. Example of this would be, where you see it showing 1.13, the STFT is removing ~13%



    You just need to adjust the MAF in that area.
    Eric Brooks
    HP Tuners, LLC

  19. #19
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    Eric, is there anyway to log the base lambda that you're trying to target?

  20. #20
    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by Turbofox View Post
    Eric, is there anyway to log the base lambda that you're trying to target?
    When you are in open loop, the parameters above work as they should.
    Eric Brooks
    HP Tuners, LLC