SteveZ

iTrader: (3)

2003 MY would not have had the wide band 02 sensor, either. IDK about newer Z's but newer G coupes got wide band sensors, if I had them my AP would tell me realtime AFR.

Anyway was it low V or high V? I am guessing low, as in lean, which would throw the code since it's inherently dangerous.

I don't see how you would ever get normal operation until the O2 sensor is in range and stays there, either outside air is getting in upstream or the bung is screwed up, something, because if it's lean you'd get that stumbling you describe. That could be caused by unfortunately a lot of things so I'm not saying the O2 sensor is wrong, it's probably telling the truth.

Problem is why - if one bank of the motor for example is showing lean, I can see the ECU pulling back the timing advance on that side, that would show up in log data. Normally I'd expect it would increase the fuel to compensate but maybe that's not happening. I wonder if the fuel the ECM is asking for is delivered, e.g. bad injector, rail has some problem like a leak, etc.

If it was mine, that's the way I'd approach it, isolate from OK, you have confidence this isn't probably an O2 sensor issue, it's measuring running lean on that side. Or if it's not running lean, but it measures lean at the O2 sensor, external air is getting in where it shouldn't. If none of that is true, then it's really running lean intermittently probably on just one bank or you'd trip codes both sides. IIRC you said something about the driving pattern, does this code kick on while you're at idle usually, or just general driving?

Which bank, then why? Culprits are fuel delivery first, i.e. test 3 individual injectors, make sure they are doing what they are asked to do. I doubt there is any leakage given the high pressures at play in the fuel injection process, but one or more under-delivering injectors could lean things out and also cause stumbling. 2003 MY is old enough that is a reasonable possibility.

Good luck and post back, what a PITA.

tnk210

iTrader: (23)

I should say that the stumbling issue only happened once (when the new ECU was installed), and I believe everything runs fine now.

I believe when Chris was checking for either the high voltage or low he got both? I know he's watching this thread so maybe he will post up his thoughts.

The code only sets while driving, typically above 3K. I know Chris has data logged the car and mechanically, it runs perfect. We spoke this morning and he basically said its a "ghost" code that is being pulled for some reason. The circuit and O2 sensor are working perfectly, so some mysterious bug is screwing with everything.

Chris had a few calls into Nissan NA and I believe they were actually having some meetings about the car and possible issues. Who knows

tnk210

iTrader: (23)

It's fixed! Got a call from Chris early this afternoon after he replaced the ECU again.

On Friday Nissan suggested replacing the ECU for a 2nd time so they got one on order and it arrived this morning. After replacement and two different drives the code never came on.

The theory is that the replacement O2 sensor I put in was faulty from the start. Somehow it caused a short on the ECU. Once the 1st replacement ECU went in that one then got zapped and a driver went bad. When the 2nd replacement O2 sensor went in the ECU was still bad. With the new O2 + 3rd ECU we hopefully seemed to have things fixed.

More to follow once I pick her up on Monday !

Scott@fontananissan

iTrader: (4)

Congrats man!!! That car was really kicking Chris's butt...but he was determined to figure it out for ya!

Scott

zvq35hr

So code P0037 heated o2 bank 1 sensor 2 came up...so i swapped the sensors from bank 1 to bank 2 to see if my code moved to bank 2 , so i can make sure sensor was bad, but the same code came up, i have a slight exhaust leak on my flex pipe only mods i have a is a muffler delete im assuming too much back pressure with a combination of an exhaust leak HELP GUYS!!

travlee

iTrader: (8)

holy dead thread revival. i posted what you need to check in your other thread you started for the same thing