drifts2

About a week ago i was driving my car when all of sudden I noticed when changing into 2nd gear and accelerating my A/F spiked to lean for a couple seconds and the car felt basically limp. After about 30 seconds my check engine light went on for for a bad Air/Fuel Ratio 02 sensor . I order the sensor and replaced it. But Now I notice when I'm driving and shift and accelerate my a/f goes lean 16-17 for like 3seconds and feels like its not going anywhere before returning to correct a/f and having power. Sometimes also If im cruising and try to accelerate and boost, I notice it will sometimes spike lean quick to 16-17a/f . I already checked for boost leaks,Spark Plugs and map sensor( I have a OMNI MAP 4 sensor)looks good its only 2 months old.What could be causing this problem
The car is boosted and its only had 900 miles since the build was complete and tuned on HONDATA.
Car idles a/f - 14.7-15.3
Under Wot a/f 11.5 ish
Cruising a/f - 14.3-15.2

liquid_helix136

It's a problem in the tune, sounds like you're using flashpro.

Basically, your tuner didn't dial in your fuel values correctly and is just allowing the short term fuel trim to adjust for it any discrepancies. Your map is too rich, and the honda ECU learns that it's too rich, and likes to "pre-adjust" the fuel value by leaning it out to compensate for the fuel map being too rich.

In my experiences, this is a terrible feature, and in Flashpro, it is under "Calibration" >> Closed Loop >> AF Learned value minimum / Maximum. I changed mine to +/- 1% in order to minimize this effect (turning it off altogether messes with other things). Your results may vary, as this feature is really kinda buggy and not fully understood.

The TRUE fix is for your tune to get fixed. Tuning the fuel values as close to correct as possible will minimize this problem. If you don't know how to tune yourself, this becomes very annoying, because in my experiences, 99% of tuners out there just tune for max power, throw a shit map for the rest of the tune, collect your money and call it a day. And then your driveability sucks.

Jaspah

Could be a leaking exhaust. If the boost is still at the same level, the exhaust manifold is probably good... but could be a small crack in the downpipe. If it leaks gas before the O2 sensor, it will have incorrect readings

drifts2

Thank you for taking your time to reply, ill have to look into my tune once i can get my hands on a windows laptop.
Ive also checked for exhaust leaks with no luck . This is definitely becoming frustrating

MorngWoodStewie

Datalog.... check stft

drifts2

What would be consider stft