What is a "healthy" O2 Level?

[freakyjason]

So i have this apexi turbo timer for my s13 sr black top which also meausres O2, air:fuel and voltage and it spits out some pretty strange O2 readings sometimes. Sometimes on the O2 setting it will just start out at around 3 and go down (a point or two a second) until it reaches around 1 and then it will start all over again at 3. However, lately i replaced my O2 sensor and coolant temp sensor and now it seems to read in the low 2 range when cold and upper 1 range (like 1.7-1.8) when warm. Is this unusual? Dont know much about this stuff. Searched and didnt find any info. Thanks!

[freakyjason]

Really? No one knows the answer?

[IanS]

Your numbers make no sense.

Air/Fuel ratio is normally reffered to as a fraction, the perfect (stoichiometric) ratio for gasoline is 14.7 parts air to 1 part fuel. Any air/fuel meter will read in this measurment, anything less that 14.7 will be considered rich, and anything higher would be lean. I would guess that you do not have the meter connected correctly, or you have it connected to a narrow band sensor, and it is meant to read a wide band signal. Either that, or its just displaying the o2 sensors voltage.

[freakyjason]

Right, well on these units (and i think in most cases) air fuel is measure x parts of o2 to 1 part fuel. The 1 part fuel is always assumed. However, i am not reffering to air fuel. I am talking about just O2. The apexi turbo timer that i have has just an O2 meter on it as well as an air/fuel meter. When on this setting it reads about 1.7 when warm. I'm not sure if this is voltage because from what i've read these numbers wouldnt make sense. Isn't O2 voltage measured from 0 to 1v, 1v being rich, 0 being lean and somewhere in between (maybe .5) being ideal? I'm really confuesed by this stupid thing and am inclined to believe that it is wired inccorectly.

[IanS]

Right, well on these units (and i think in most cases) air fuel is measure x parts of o2 to 1 part fuel. The 1 part fuel is always assumed. However, i am not reffering to air fuel. I am talking about just O2. The apexi turbo timer that i have has just an O2 meter on it as well as an air/fuel meter. When on this setting it reads about 1.7 when warm. I'm not sure if this is voltage because from what i've read these numbers wouldnt make sense. Isn't O2 voltage measured from 0 to 1v, 1v being rich, 0 being lean and somewhere in between (maybe .5) being ideal? I'm really confuesed by this stupid thing and am inclined to believe that it is wired inccorectly.

You are correct, Nissan's do indeed use a nernst cell o2 sensor that reads 1 volt for rich, and 0 for lean. I didn't think about that, your readings could not be voltage, it would have to be some other reading. Without knowing what those numbers are actually referencing, its hard to say if the readings are good or bad. Do you have the instruction manual? Either check that or the companies website, it may be a percentage reading, I'm not sure, and I'm too lazy to do the math. I have a wide band sensor and gauge, and at idle I read near stoich at idle when warm, and around 11.5 when cold.

[freakyjason]

Yeah, i didnt think it could be voltage, that's why i was kinda confused. I just looked at an online instruction manual and it has a section with a title that leads you to belive that it will explain how the O2 readings work and what they mean but all it says is how to calibrate it. At this point i'm kinda stumped. Unless some one with the same unit has some understanding of it that i do not, i don't really know where else to look for info. Maybe call the manufacturer?

[IanS]

i don't really know where else to look for info. Maybe call the manufacturer?

Possibly call a certified distributor/installer, that way you can talk to someone who has most likely dealt with your specific unit.