Nistune Forums

I'm not familiar with the style of O2 sensor used (titania) since most of my tuning has been domestic, but I assume it should function the same.

Car has stock MAFs and stock injectors with HKS GTSS turbos + HKS dump pipes... there are adapters to screw in the smaller titania O2 sensors which may or may not be throwing off readings?

Anyway, they do not switch at idle after sitting for a few seconds: they sit at 0. Rev it up a tiny bit and they will switch back and forth properly. Wideband shows 16-17afr or so at idle and fuel trims creep negative.

Bad O2s? They appear to be switching correctly at other throttle positions.

Got everything working well at idle.

I went in and made some adjustments with closed loop disabled and everything worked fine after I turned them back on. O2s switch fine at idle now.

Hooked back up today and idle AFRs are moving around a bit.

Stft immediately went +10 and ltft worked it's way to +7 after it warmed up. Drive around doing some wot adjustments and after stopping Stft settled to -7 and ltft was -10. Afrs at idle will creep up to 16-17 and eventually move back and forth with low 14s.

With fuel trims disabled the tune has it sitting at 14.7 pretty consistently so I'm thinking I may just ignore what the narrowbands are doing.

Sounds like the narrow bands are reading too rich which is why your trims are going negative

Assuming the O2 sensors are correct type (and this ECU is in an R32 GTR) then I'm not sure why its reading too rich unless your base tune is out

You may need to increase your injection multiplier richer until your trims gravitate towards 0%