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Thread: AFR Error % questions..

  1. #1
    Advanced Tuner
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    Jan 2006
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    AFR Error % questions..

    I have a 1 bar SD OS. Trying to get this thing to be close to 14.7 at cruise. I disabled Ltrims and also bumped CL Enable to 250 in hopes it keeps from using STFT / LTFT's. Trying to take any automated stuff out. Not sure I need to do that but think it might help.

    Ok.. Here are my questions.

    What is logged in the scanner under the AFR Error histo, do I multiply my VE by that number? Or do I +/- that number to the VE.

    I understand commanded AFR is 14.62857 under the "General" tab under Fuel Control. Is there a way I could set something to say 12.8 and use the AFR Error % to adjust my VE for WOT? Or does PE still multiply this by 1.143 when the PE thresholds are met?

    I think that's it for now, hope the above makes sense..

  2. #2
    you can cammand any AFR in the open loop EQ ratio table.
    98 Z28
    stock ls1 engine,A4,Fast 90/90,SLP lid,Ms3 112LSA,LT Headers,TCI 3500stall,semens 60 inj,ASP under drive ,3.73 gear,11.82 1/4 .sold

  3. #3
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    Is that scanner side or tune side?

  4. #4
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    Using the cut and paste special feature, use the actual % above about 5%, below that, do it by 1/2. If you change the commanded AFR to 12.8, it will shoot for that while cruising and any thing less than WOT, not what you want. You want the ECU to get 14.7 while warmed up and at cruise, use different tables to adjust for the other times, (cold start, idle, WOT, etc.)

  5. #5
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    did u look at the user submited help file that tells u how to tune in speed density?
    2000 Firebird,2002 O.S.,LQ4 370,Borg Warner S475,truck mani.,Eagle crank,Callies Compstar Rods,Wiseco-11 4.030 pistons 9.4:1 comp.,LS3CNC heads,LS3 intake,NW92mm throttle body,ID1000 injectors,BTR trunion upgrade,LJMS STG3 cam,LS7 Lifters,ARP Studs-bolts,Frozen Boost A to W intercooler,JGS 60MM BOV,2 40mmJGS Wastegates,4L80E trans wth segment swap,CircleD 3400 single disk,MOSER 12 3.31gears ,BMR K-Mem.,2 Walboro 450 pumps,Returnstyle fuelsystem MAGNAFUEL regulator.
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  6. #6
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    Well, disablig the Ltrims and bumping closed loop to 250* really allowed me to nail idle fairly quick. Had I used AFR err % vs looking at what my wideband was telling me, it would have taken longer. Swaping to the Super Vic really made my pull a lot of fuel out. I had to reduce 400-800-1200 by a good 40% to move it from a pig rich 12.1 to a still semi rich 13.8..

    Comanding a non load 1600rpm idle through the VCM controls also allowed me to work on that section a bit. No longer low 12's but a stable high 13 afr as well. Tomorrow I will drive it and work on other areas..