I have been trying to finalize the tune on my supercharged 2007 S2000, but AFR seems to be changing without any changes to the tune. I went out and did 5 back-to-back 3rd gear WOT pulls on the same stretch of road without so much as turning off the engine, let alone changing the tune. Here is a comparison of run 1 and 5:
https://drive.google.com/file/d/1ehryCi ... sp=sharing
Run 5 was a full point richer and was measurably slower, a lot of it was rich beyond the sensor range. MAT and ECT were both ~8 degrees warmer by the 5th run, and based on the compensation tables, the only effect should have been a slight leaning out on the last run due to the MAT High-load comp table (both runs were above the range of the ECT compensation table).
Am I missing something? What else could be affecting fueling if not the MAT and ECT compensation tables?
Things I have already tried:
Injectors professionally cleaned and tested Sat
Replaced MAP sensor
Replaced Fuel Pressure Regulator
Inconsistent AFR?
Re: Inconsistent AFR?
Compare fuel pulse to see if that's changing or it's related to the O2 sensor.
Long term fuel trim can alter overall fueling as well.
Long term fuel trim can alter overall fueling as well.
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Re: Inconsistent AFR?
I was under the impression that WOT fueling was open loop and not affected by LTFT. Am I mistaken?
Re: Inconsistent AFR?
Long term is always applied. Short term, you'll notice, switches to 0 when out of closed loop.