bjr

After many years of wrenching on my cars and family/friends this is the first o2 sensor I have ever seen. So let me know if the white residue seems normal. Reminds me of the same look I get on most of my used spark plugs.
Also both measured same Ohm value on the bench next to each other, definatley same temperature. Other readings I took were on different days. I'd say like most of you suspected my sensors are just fine!

http://postimg.org/image/bv0qhtayd/

http://postimg.org/image/f357uux85/

adrift_foolish1

Yep, looks like you're down the wrong rabbit hole

iStan

iTrader: (29)

So you swapped the sensors and they are still reading the same as before? That is why I choose not to go down the sensor route. I still haven't had time to put the TP on but it should be soon.

I forget, what CATS do you have? (stock, hfc, tp?)

bjr

Felt like I had to verify the sensors before finding the cause just in case.

My car is stock 2005.

The heat shields are coming off the cats but I haven't read anything about them causing irregular sensor readings that I can find. B1 is missing the bottom half and B2 is still all there but very loose and moving around, nearly split in half to fall off the bottom too. I guess I should mention this but I cannot believe it would matter with my "problem"

I'll keep after trying to find the reason but I'll probably need some guidance on the rest of this. I guess I could have gotten to this point on my own.

iStan

iTrader: (29)

The heat shields shouldn't cause a problem (on the basis that TPs don't have heat shields and this doesn't seem to cause a problem). I would do the smoke test. With the heat shields that damaged, I wouldn't be too surprised if you discovered leaks.

iStan

iTrader: (29)

Finally put the tps on and it looks like I'm getting the same readings as before. I am going to try a new o2 sensor in the upstream passenger side since that is the one with the odd reading. Arg.

bjr

In your case this may be a good next step. The code you pulled did say something about the O2 signal range or performance. Maybe it is starting to fail or has got build up on it causing slow readings. It sounds like you have a reason to at least suspect the sensor based on the code.
When you put a scanner on it and watch live data does B1S1 react as quick as the others?
I'm still waiting for the weather to break a little. We get 4-6" of snow every few days for the last few weeks. I'm not in a hurry to fix it when the garage is in the 20's. I've got bigger things to battle at the moment.

Good luck!

iStan

iTrader: (29)

Well, when I logged it last night, I realized my B1S1 will not read over .30. I was originally thinking some issue with the cat was causing the low reading, but now it looks like the sensor just can't read properly. I'm waiting for the check engine lights to trigger and see what codes pop now.

bjr

If you have the FSM and an Ohm meter you could check the resistance of B1S1 to see if it is in spec. while you are waiting for your next code to pop up Would be one more piece of data if you haven't done that yet. That side is pretty easy to get to the connector...

iStan

iTrader: (29)

I'm waiting for a code to pop. It should have triggered by now but it still hasn't. I may have lucked out and fixed it. And with that statement, I'm fully expecting my car to have a Check Engine Light on when I start it in the morning.

bjr

Off work today and it's warm! Summer is on it's way

99% sure no exhaust leaks. Took my pressurized smoke can (regulator, paint can, hose, burning paper towels in the can) and tried the best I could to find a leak. Started tje smoke and put duct tape over one muffler tip, cut a slit and taped the hose into it. Had smoke pouring out the other tip. Stuffed a rag in second tip and looked for 15 minutes for other leaks in the system. Cannot find any!

Not sure if I should give up until computer tells me I have a real problem. Would like to understand the software better. I would have guessed if S1 reads that low (.3) that the fuel trim would increase and attempt to bring the S1 reading higher. The fuel trim is very responsive (with respect to time) but do the decisions to add more fuel come in response to a much larger window on the O2 sensor? So for example, the fuel trim would never add more fuel than the regular fuel map is programmed for until the O2 sensor reads in a much lower range (like 0.1 to 0.2)?

Is it that the fuel trim changes constantly to all the other variables like load, TPS, RPM, etc etc. and the O2 sensor is a final check? And JUST a check, not a constantly changing feedback adjustment to get A/F ratio about ideal?

I would like opinions if I should do anything else. I guess there is nothing to gain like better MPG or that I am neglecting something that will fail early. The spark plugs always have looked the same on both banks. If the fuel trims are pretty equal on both banks I guess the car is just running normal and nothing needs to be done. Still puzzling to me and wanted to learn more...

Bigsyke

Funny, my readings are the exact same as yours --exactly the same. The exhaust harmonics seem to be off, which led me to check if one bank is truely lean.

I have an ultragauge, and I've seen b1s1 dip down into .200, while b2s1 is at .600.

I too would like to know if this is normal

brad6080

I know this is a old thread but has anyone made any progress with this? My 07 automatic is doing pretty much the same thing. b1s1 reads roughly half of what b2s1 does, but b1 doesn't seem to be cycling as much as b2. B1 ranges from .256 to .550 and b2 was .680 to 1.200 on a drive earlier today. Keep getting random p0420, p0430, and p2a00 codes but never the same code twice in a row and never more than one code at a time. Car has hfc's with stock y pipe going to a single exit exhaust, other than that stock as far as i can tell. Just got it a couple months ago with these mods already on it. Car has a slight hesitation when i first hit the excelerator and a strong raw fuel smell pretty much constantly.

karlt

Brad6980 (and all others who have seen this problem),

Your readings are normal, and here's why.

MY2003 and early MY2004 Zs used narrow-band O2 sensors to measure air/fuel (A/F) ratios. The output voltage of these sensors swings between approximately 0.2 Volts and 0.8 Volts as the ECU chases the optimum ratio, 14.7:1. In mid-MY2004 Nissan changed over to wide-band O2 sensors, which output a steady 1.5 Volts when the engine is operating at 14.7:1.

OBD scan tools, and devices like the UltraGauge, request information from the ECU by transmitting a parameter ID (PID). The OBD specification contains different PIDs for narrow-band and wide-band O2 sensors. The narrow-band PIDs send back values between 0 and 1.275 Volts, while the wide-band PIDs can return values between 0 and 8 Volts.

Nissan apparently decided not to use the wide-band PIDs when the sensor change was made, but to scale the wide-band voltages into the narrow-band range and report them using narrow-band PIDs. Perhaps their factory diagnostic tools at the time couldn't access wide-band PIDs. In any case, to further confuse us all, they scaled banks 1 and 2 differently, so that at an A/F ratio of 14.7:1, bank 1 reports 0.3 Volts and bank 2 reports 0.6 Volts.

Hope this helps.

bjr

That is embarrassing how much time I wasted on that! I was just trying to finish up a misfire problem at the time and check everything i could. How in the world did you figure that one out?!

I had forgotten about this and it does make me feel better even though there has been obviously nothing wrong with my car. Thanks for setting us all straight!

karlt

Glad to help.

NarcisoG.

NarcisoG.

hillball88

Sorry for old question. I have the same exact two codes that you kept getting it replaced all 4 sensors as well. Were you able to fix the problem and thank you