Here’s some information on the R1250, which is supported by data coming from the GS-911. As most know, the R1250 has three oxygen sensors: two are in the headers, one per cylinder, located ahead of the catalytic converter. Those two sensors are used for precise fueling control by the ECU. The third sensor is after the cat and will monitor to make sure the fueling is stock (or within range of stock) and that the cat is doing its job. It’s an automated environmental police officer. Apparently no one has looked at the O2 sensor till this week. A new friend volunteered to run some gs-911 logs and take some pictures in preparation for an AF-XIED trial. The pre-cat O2 sensor has a new connector and five wires. BREAKING NEWS The two oxygen sensors ahead of the cat are WIDEBAND O2 SENSORS. Simply, this means BMW will be able to set a MUCH broader range of AFR targets but they will still have to satisfy the Euro 4/5 guys and keep the cat happy. It also means a radically different ECU code since the Wideband O2 is programmed, controlled and monitored in a very different way. IMPACT It will take some time to develop strategies to alter via add on or to recode the ECU. And it will take time to learn how to deal with the 3rd O2 cop. And the fueling of the R1250 is probably very good as it is. However since the engine has to run lean to meet the operating parameters of the catalytic converter there will be the possibility of improvement. But it will take time to know just how to achieve those goals and keep the R1250 as good as it already is. As a community, we should spend some time and learn the new ECU control system to see what improvements can be made.