Hello All

Question on disconnecting the primary O2 sensor and the affects long term? My current setup are as following; Greddy Turbo kit, AEM UEGO, AEM Truboost, Greddy Turbo Timer, Greddy POV and custom 3" exhaust with performance cat. The car was recently tuned with the E-Management ultimate and basically reconfigured the injectors to increase boost at lower RPM and take fuel from the high power band to offset the fuel. The car ran 234whp/196.4twp after several runs. The following week I was finally going through all the stock items and noticed the O2 sensor sitting in the box. To save time, I went to the shop the soon after and they installed the O2 with no issues. The thing that I have noticed the car doesn't run as rich but starts to "buck" more often. It seems the ECU and E-Manage are in a consistently struggle for command while in low boost. I decided for the time that I would remove the O2 sensor since the car was tuned without the O2 sensor. So... Will I regret in the long haul if I continue to keep the O2 sensor off the car?

 

usually with the primary disconnected it will throw a code. at least on previous models and OBD configs. pretty much once you have a device that will alter stock fuel maps the O2 is not really utilized. you just need it plugged in so that you dont throw codes. at least that is my experience with both of my preivous turbo'ed setups on my old civic. boost and the new civics is something that I have to learn.

 

The primary O2 sensor is there to allow the ECU to run in 'closed loop' mode: meaning it takes a reading from the O2, and adjusts fuel accordingly to allow for best gas mileage and lower emissions. Hondas typically use a 'narrowband' sensor, one that can only tell if it's too rich or too lean, but not by how much. That's why you have to go out and get a 'wideband' sensor to tune with, because they tell you exactly what the AFR is.

Closed loop mode is only used during part-throttle and cruising, when you floor it, the engine just reads off the fuel maps and ignores the sensor. If your car is running well and your gas mileage stays consistant without the sensor, then I'd say leave it off.