Hondata

OK tuned a buddies car b20 vtec. S300 well like a few weeks later he called said wideband is stupid rich. I get there hook the laptop up and the ltft at idle are -1 and the stft just keep going posiive and climbing and climbing and climbing like till they can't go any further. But ltft do not change I stuck it in open loop for now. Could a bad 02 be freaking it out or something. How do I reset fuel trims bc even in open loop it keeps saying -1 ltft like it just won't go away.

Without the calibration and datalogs showing the issue it is hard to say what it could be.

How do you reset the fuel trims ? I'm used to hptuners and I just hit reset fuel trim on the scanner but I don't see a way on hondata s300. Also no matter what the ltft stay -1 open loop closed loop thev the stft go out the roof it doesn't matter how your driving hard slow fast its just stuck at -1 I just wanna reset the ecm to where it hasn't learned fuel trims or anything.

Unplugging the ECU will reset it.

this always cause by bad O2 sensor. please swap/change and retry.

check for exhaust leaks (e.g. at the center bullet) and weld it up.

besides unplugging the ECU, you can also richen up or lean out your Overall Fuel Trim, so your STRIM go rich or lean, after which your LTRIM will adjust while revving to 2000 rpm

U need to check your idle and cruise fuel (or where ever u drive 90% of the time) - it cant be too rich or lean

Is your O2 lazy? i just swapped mine out and was amazed (after welding up the leaks)

u also need to post the cal & log.