Printable View
Hi guys, I have been noticing in my scans that my O2B1 varys wildly from around 50mV to 900mV. It seems to be somewhat periodic, but the frequency at which it fluctuates seems to vary. Is this normal? If not, what could be causing it? Is the sensor bad?
Attachment 95692
Narrowband o2 sensors are suppose to swing lean and rich of stoich or in crude terms, ~450mv.
How old the sensor is and where it's placed in the exhaust stream will change how it reads. If the sensor is still working okay and the fuel trims aren't complete garbage one way or the other, you can venture to say the o2 sensor is working good.
This is why a wideband o2 sensor is really needed for fine tuning air fuel ratio's. That sensor/gauge is far more accurate than what a narrowband o2 sensor can tell you.
Sounds good, just wanted to confirm that it swinging back and forth was normal operation
When you get on the throttle and get into the power enrichment, the oscillating 02 will stop and hang above 750, The richer the higher mv it will show. But there is no way to decipher if 900 mv = 11:1 afr or 13:1 afr. It only tells you your richer than stoichiometric.
Like 5FDP stated, that's why we need a wideband oxygen sensor to tune full throttle AFR.
Some cars come with Wideband 02's, but most cars have narrowband 02's.