O2 sensor turned off in custom tunes, why?

vzrDean1800

.040 Over
Joined
Sep 25, 2018
Messages
62
Location
Elora, ON Canada
Ride
Suzuki M109, 2012 Rocket3R
Hi All, Ive noticed when I download custom tunes for the rocket, then look at them using tuneecu, most have the O2 sensor turned off! Even the tunes using factory exhaust with TORs. Anyone know why?
I'm new to the rocket, but trying to learn all I can.
Thanks,
 

John Miller

Supercharged
Joined
Jan 3, 2018
Messages
231
Location
Brisbane, Queensland Au
Ride
2011 Rocket 3 roadster
A custom tune will be out of range for the STD narrow band O2 sensor, which only when 14.5:1 AFR is active in the fuel map such as when idling and in the lower RPM Cruise mode(s). The STD O2 sensor only tells the ECU if the AFR has not reached the point of 14.6:1 AFR like a switch to confirm correct mixture. A custom Tune and mapping will not work with a std O2 sensor as the AFR is generally way out of range for a narrow band O2 sensor to functon, Custom / Dyno tuners use a wideband O2 sensor to actually measure and confirm real time AFR and adjust the fuel mapping and ignition timing in some cases to meet the requirements of both the rider and the engine configuration, this wideband O2 sensor is removed after the tune is completed. Some Auto-tune systems are available with their own O2 sensor such as the PCV but they also require replacement of the STD O2 sensor and it still must be disabled through the ECU. That is the reason why O2 sensors are disabled in Tune Ecu with a custom tune.

BTW - some custom tunes still utilize the O2 sensor function and leave the O2 sensor switched on, if that tune has been developed that way then simply follow the tuners advice (as long as you can trust it).

I hope I haven't confused you totally, If I have then - sorry for that.

John
 

DEcosse

If it's no Scottish it's CRAP!
Joined
Jun 8, 2011
Messages
1,901
Location
Bay Area, CA
Ride
Triumph Daytona (Custom)
short answer - the O2 sensor will attempt to re-trim any changes made to fueling tables and thereby will negate them using closed loop control; disabled means it will run open loop and simply apply the mapping elements
 

R-III-R Turbo

Mine is the biggest :)
Joined
Oct 12, 2010
Messages
1,496
Location
Ireland
Ride
2.5L Stroker Rocket III, 04 Hayabusa
News just in wrt PCV and AT, Dynojet have apparently changed their setup so that the stock O2 sensor is now retained.
A hole must be drilled and boss welded in to take the AT's wideband o2 sensor.
Direct from Dynojet themselves, the reason is that "This change was made because a vast majority of bikes gain nothing with removing the factory sensors and also to meet US emissions compliance."

In this case, there is no o2 sensor blanking plug anymore and the box in (TuneECU) remains ticked.
 

cootertwo

Top Fuel
Joined
Mar 24, 2013
Messages
1,588
Location
Labelle Florida USA
Ride
2013, & 2 05's R3R, 2006, 2004 Harley's, 2004 Kaw
OK, without looking, to disable.... put a check in the box, or take the check out?????
 
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