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Old 01-15-2015, 11:47 AM   #2202
j_Zer0
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Join Date: Jul 2014
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RE: Post-flash ECU learning

I went for a drive last night after completing an OFH install + flash to stg 2. With my OFT set to display real time diagnostics, I could see the ECU learning (or at least the evidence of ECU learning). I'd originally had an issue (loose O2 sensor) that was causing high LTFT, but now that I had that sorted out I could see LTFTs go from 15% to 8% to 5%...finally down to 1%. What was most interesting was the WAY the ECU appeared to be learning: if I maintained constant RMP it would figure out how to stabilize fuel trims for that RPM. Once RPMs went up or down LTFT would shoot back up to 15%, but if I maintained the new RPM LTFTs would begin to stabilize. As expected, if I returned to an RPM range the ECU had already sorted out the LTFT would immediately go back to 1%. I found the following method to be the quickest way of getting my LTFTs to stabilize: find an RPM range where LTFTs are high and maintain that RPM until LTFTs drop -- rinse and repeat.

I'm sure this isn't news to many of you, but maybe it will help someone. Thanks.
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