Originally Posted by Mitco39

Jordo,

Your probably correct, I do know that it is very touchy as to when it switches from open to closed loop and just a small amount of load will trigger open loop. If anything as soon as my car goes open loop it runs very rich (which was the main point of me starting to look at my own tune, I wanted to cut back on the fuel a bit as it does at time drop below 10:1).

With my experience in dealing with this automotive ECUs just turning off the codes associated with a sensor will not stop the ECU from reading and using this sensor. If it is there it is going to use the data. I have actually ran into issues where just simply turning the diagnostics off and assuming it was dead caused issues. You need to physically unplug or cut power to it to stop the ECU from using it. I think my particular issue is that both my downstream 02s are side by side on one bank which could be causing this whole mess. Ill know more once I find time to crawl up under the car and unplug them.

There is no way that a MAF is causing the ECU to do this. If the MAF was reading high or low you would see it in the trims and the corresponding AFRs. Same with the primary 02. Nothing like that explains why the ECU is seeing rich, yet adding fuel.

I wonder if any of the Uprev tuners have ever seen this issue? I have seen it across multiple message boards all the time no one with any real affiliation to Uprev has commented on any of the threads. I might try logging a few other 370Zs and see if its just me or if everyone is having similar issues.