RomRaider

Hello all, I am trying to find out if there is a way to change my ZB010 ROM to base both bank AFRs on BOTH wideband sensors (both are mounted post Y pipe now). Currently if one sensor reads leaner than the other just due to environmental differences between the two sensors, the ECU adjusts that bank to be rich as all hell and turning up injector pulse width by almost double in that bank. At idle in closed loop I was shocked to see over double the pulse width in one bank. no wonder it is running rough. The expected immediate response from richening a single bank is not occurring as both sensors are getting an average from the entire engine. I don't want it to richen either bank individually anymore. Also, is there a way to change expected primary O2 delay since my widebands have moved about 2.5 ft away from the factory location (right next to exhaust valves) Thanks

How did you lengthen the wires to the WBO when reinstalling.
If possible, show a photo of the wires.

Yep there is a bit to convert to single bank. It will use the bank 1 sensor. You could leave the B2 sensor there but it won’t do anything. You may still be able to log with it for verification that the B1 sensor is working.

I’ll need to test this on the TB48 the first time I tune a turbo one. I suspect that all reflashed turbo TB48s currently out there would have the same issues you’re describing unless they’re twin scroll with the O2 sensors pre-turbo.

That’s for the downstream O2 sensors only. There’s no known flag that allows for a single bank upstream O2 sensor on a V6 engine unfortunately. The entirety of the wideband coding would need to be modified to support only a single sensor. Analyzing the AFR control system between single bank and dual bank AFR sensor vehicles would potentially yield interesting findings.

Althouuuughhhh, a potential solution would be just having one of the bank’s AFR conversions be used to set the other bank’s respective RAM parameters. Then by setting the unused banks STFT and LTFT parameters to constant 100%, you could honestly probably get normal operation. Since all the wideband voltage diagnostics would still pass, and the AFR reading would pass diag as well since it’s 1:1 with the main O2 sensor. Haven’t spent much time looking at the upstream O2 sensor code, so do note that this is all hypothetical and entirely untested.

Really? Are you saying you are 100% sure that mfOSCBANK "A control choice flag for the bank" is for downstream sensors only?

That's basically what I would like to do, although I heard uprev has a single wide band hack. I personally don't know for sure because I don't have uprev. If there's no immediate software solution that I can do in this instance, then I may have to buy a couple more bungs and have a buddy weld them in the right places. These are just OBX headers for an Altima and they don't even say they fit mine, but I made them work, but they only have bungs on a single runner of the headers, a few inches from the exhaust valve, getting exhaust from a single cylinder, and then, those don't even fit my O2 sensors because one of them faces power steering and the other wasn't welded with good alignment so the O2 sensor won't even go in because it's not lined up with the hole they made in the pipe. So they're at the test pipe but, it really screws up factory logic, as the computer sees no immediate or discernible response by adjusting a single bank. Instead, both sensors will read richer or leaner, but one is not going to read more or less than the other If at the time it happens to be reading leaner or richer than the other. At idle, I've watched the closed loop injector pulse width be 2.65 ms in bank two, and 5.5 ms in bank one.

Oh, I thought you were referring to mfF2IN1. Have you messed with mfOSCBANK and found that it actually results in a single bank upstream O2 sensor system? It definitely seems like Nissan shares a lot of the code across various models. Because when I checked the wideband conversion function for an I4 Altima and Sentra, they both shared the same code as the V6 Z. Even though the altima is confirmed to only have one upstream O2 sensor and the sentra either has two upstream O2's or one upstream O2. And they all have six bytes for the cylinder fuel trim, but it's presumably limited to only 4 for both of them in the code. So it's honestly more possible than I originally expected.

I know you don't have UpRev, but would you be able to provide any verification that UpRev does in fact have a single wideband hack? Because if so, that would confirm that there's a flag that exists for such a function. I know they have a single narrowband hack, but I can't recall anything related to the wideband sensor. But it's certainly a possibility that they do.

I never got around to playing with this before I sold my car unfortunately.

Another possibility would be if it was simply a matter of removing the bit for B2S1 and B2S2 O2 sensor position bits from the mO2S byte.

I can't speak for Nissans but I've seen on other platforms that they have a single bit switch to change everything from dual bank to single bank. People use it for single turbo setups on the BMW N54 for example. I always presumed that the Nissans would have something similar.

Ahhh, but you definitely could be right about there being a flag for it! Originally, I kinda just threw away the possibility since V6 = Dual Bank, can’t argue with physics. But it appears that Nissan truly does just copy + paste the AFR control system code across all wideband models to at least SOME degree. So the odds of them using a flag to distinguish between single and dual bank is pretty high imo.