I've been tuning my '08 XB12 with BUE2D firmware and a single wideband sensor in the front hole. I've encountered an issue with MLV when I look at the rear hole and its NB derived EGO corrections. AFVs locked at 100%, closed loop enabled via the rear cylinder. I end up with a front EGO correction of 100% due to the WBO2 being present, the rear EGO correction is normal with the NB sensor. When I use VE Analyze, I have to select the AFR Field and the EGO Correction Field, which is straightforward for the front cylinder with the WBO2 since the AFR field is just the transfer function computed for the sensor and the EGO correction is 100% since there is no NB in that hole. However, when I look at adjusting the rear cylinder with the OEM NB sensor, I'm not sure what to select for the AFR Field. As a test, I set the EGO Correction Field for the rear cylinder to the front EGO correction field (which is all 100%), selected the Narrowband O2 for the analysis, and still ended up with adjustments made to the map. I was expecting no adjustments to be made due to the EGO Correction Field being set to 100% everywhere and the NB selected for analysis.

To avoid this problem with the cylinder that has no wideband installed, I just multiply the wideband-less cylinder's fuel map with its closed loop EGO corrections in Excel and use that instead of the output from MLV. Has anyone else encountered this?