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Old 07-17-2015, 07:06 PM   #176
Mach828
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Join Date: Nov 2009
Location: Albuquerque, NM
Posts: 5,759
Re: Thread for those of us who tune our own cars

Bump!

So I finally figured out my stft issue. I learned that there is an additional parameter to closed loop fueling. The closed loop bias tables. What these tables essentially do it tell the ecu that a discrepancy from lamba on the 02 sensor reading is normal and not to adjust fueling so much. I checked the stock bias tables and they were all over the place. Which may be fine for a stock car from the factory, but with 10+ years of wear and so many mods this data is likely not accurate anymore.

What I did was zero them out to start. Immediately I noticed steady stft, where before they would swing all over. I checked my stft, and adjusted the "lazy" bank so that the ecu would accept the variance and not change the fueling so drastically. To some extent this may be limiting their ability to adjust fueling, but they should only be making minor adjustments anyways if the tune is solid. Pretty excited!
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Vortech V2 S-trim, E85, A2A Treadstone, Comp cams, built engine, full exhaust, built rear, built 4r70, more mods.

Tuned by me with SCT Advantage
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