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Thread: LUJ E78 commanded afr help

  1. #1
    Potential Tuner
    Join Date
    Dec 2018
    Posts
    2

    LUJ E78 commanded afr help

    Hello all, I'm just getting into my 1.4t Cruze and I'm trying to figure out what values need to be changed for running a 30% ethanol mix. I've calculated stoich to be 12.99:1 and PE to be 10.19:1 I was expecting to see the easy button for commanded afr in the fueling tab but its not there. Also not seeing where I would set the pe afr's either. I know the easy way would be to put the alcohol sensor in and turn flex fuel on. Wondering how to do it the old school way for now

  2. #2
    Advanced Tuner
    Join Date
    Apr 2011
    Location
    Chicago, IL
    Posts
    763
    stoich will be under engine/fuel/general - stoich afr - and since there isnt a flex fuel sensor and if your sure that your stoich will be 12.99 just put that in the whole chart but the problem will be when your not running 30% anymore because the ecm cannot control commanded stoich due to alcohol percentage so you'll have to change it back
    so save a different tune for your 30% mix and for running just regular pump fuel
    pe will be under engine/fuel/power enrich - eq ratio(gas) - again without having a flex fuel sensor the ecm will still reference the (gas) not (alcohol) because it doesn't know your running e-85 and then tune your airflow models and wot with a wideband
    to figure your commanded afr during pe take stoich and divide it by whatever afr you want and thats your eq ratio ... ex 12.99/11=1.180