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EJK and O2 sensor email response from Doebeck

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So I thought I would share this. A member either on here or maybe it was FB claimed his EJK was throwing his bike into a 10.2 or so AFR range with the O2 sensor removed. 


I reached out out to Doebeck and explained his process of analyzing his experiments with their product in the manner he referred to on this forum and asked a general “wtf” is going on with this. This is the response I got from them :


On Nov 9, 2017, at 3:01 PM, Dobeck Tech Support <tech@dobeckproducts.com> wrote:

Thank you for reaching out.


You do not need to run the O2 sensor with the EJK installed and it is recommended to disconnect the O2 sensor when the EJK is installed. If you choose to keep the O2 sensor hooked up to keep the bike emissions compliant and street legal, you would need to set your green fuel zone to the 0% fuel change setting as to not conflict with what the O2 sensor is doing.


When the O2 sensor is disconnected, the FZ-07 runs around 13.5 AFR. We have this on video from our initial testing and may even be posted somewhere on the FZ07.org website.


It is likely this individual ran the EJK with O2 sensor connected for some time. If the EJK is adding/subtracting fuel while the O2 sensor is connected, the O2 sensor will continue to regulate the fuel to target 14.7 AFR which is what these sensors are designed to target. The O2 sensor sees the change in fuel from the EJK, over time, this can cause the ECU to switch to a different fuel table to operate off of which may be why he saw an overly rich AFR when the O2 was disconnected.


Do you have an EJK on your FZ-07? I’d be happy  to help you tune it.


Let me know if you have any questions.


Tech Support | Dobeck Performance
1-406-388-2377 | tech@dobeckperformance.com
157 Progressive Dr | Belgrade, MT 59714

www.DobeckPerformance.com | www.Facebook.com/DobeckPerformance


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Additionally I’ll note that before I installed my EJK I had been running my bike without the O2 sensor connected for some time so my bike was likely running off its “safe mode” or “fall back” map since it was no longer getting any info from its O2 sensor. 


When connecting my EJK I left the O2 sensor uninstalled and have been running it uninstalled  since installation of EJK unit.

Edited by crsnhppr

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I run the PCV with autotune and the stock O2 removed. Seems like a superb setup. The 10.2AFR he is experiencing is most likely coming from what Dobek stated. He may not have changed that Zone to 0% making it run richer. It's difficult to do unless you have a wideband hooked up to see what is actually going on. With my autotune on the PCV, the wideband takes care of all that for me with my preset AFR tables. I set my tables to 13.2AFR and 13.5 in the cruising ranges and it runs like a beast. I tried around 14AFR for the cruising range and it ran terrible. 13.5 and it cleaned up nicely.

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