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Thread: Open loop f/a vs CT vs MAP

  1. #1

    Open loop f/a vs CT vs MAP

    Can we set up a graph to tune the olfa for lean/rich when cold. My 5.3 idles at 14.2-14.5 when cold but any amount of throttle it goes to 18+ and sputters. Just looking for a quicker way to dial it in vs trial and error.
    I'm thinking a graph with MAP=row axis coolant temp=column axis and plot eq error, log>copy>past special add any reason this wouldnt work? Thanks

  2. #2
    Tuning Addict 5FDP's Avatar
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    The open loop eq ratio isn't really a table you change like that, those are just values you are requesting and the airflow model is what you fix to match that.

    So if you are having lean or rich issues when you open the throttle blade you have an issue with your MAF or VE tables or both.

    But remember that the open loop eq ratio changes as the temps rise because it makes it way towards 1.00 (stoich). Factory will have it setup to run richer until the coolant temp is over 130-140 and then asks for 1.00 or closed loop to take over.

    If you are tuning in open loop all the time you could ask it to come up to stoich quicker. Plausible that you have running airflow settings or something like that causing too much to come in at idle or when coming back to idle too.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.