Off idle stumble

[Andyb43]

Thought I would share this with you all, I have a 2012 ST, ecu flash, full arrow exhaust.

i was running the standard front pipes and an arrow end can I then fitted the front pipes and it was great making the engine so free but it developed the off idle judder which was so annoying in traffic that I was about to refit the standard front pipes. I did the 3/4 turn and TB balance plus clutch basket Change stll had it.

well I unplugged the O2 sensors and now have the smooth old S10 back. No error codes or warning lights and she runs as smooth as when I bought her. Now no off idle stutter and rolls smooth from tick over.

one happy owner. Just need to repack the can as it’s a bit loud now.

 

[bimota]

Thought I would share this with you all, I have a 2012 ST, ecu flash, full arrow exhaust.

i was running the standard front pipes and an arrow end can I then fitted the front pipes and it was great making the engine so free but it developed the off idle judder which was so annoying in traffic that I was about to refit the standard front pipes. I did the 3/4 turn and TB balance plus clutch basket Change stll had it.

well I unplugged the O2 sensors and now have the smooth old S10 back. No error codes or warning lights and she runs as smooth as when I bought her. Now no off idle stutter and rolls smooth from tick over.

one happy owner. Just need to repack the can as it’s a bit loud now.

can i ask,

are you saying it was flashed with full arrows exhaust, BUT the O2 SENSORS were still connected

OR it was flashed with standard front pipes and arrows can but still had the O2 sensors attached and when you put arrows front pipes on all you had to do is unplug the O2 sensors thats strange , having a flash with o2 sensors still attached

rob

 

[Andyb43]

can i ask,

are you saying it was flashed with full arrows exhaust, BUT the O2 SENSORS were still connected

OR it was flashed with standard front pipes and arrows can but still had the O2 sensors attached and when you put arrows front pipes on all you had to do is unplug the O2 sensors thats strange , having a flash with o2 sensors still attached

rob

Hi rob, flashed with std front pipes and arrow can, never told to disconnect o2 sensors. It didn’t make much difference until I put the front pipes on.

 

[Cantab]

When i got mine flashed a year back was told to un plug the O2s and its been fine has a K&N , Arrow header and a Euro 4 Akro pretty quiet i must say.

 

[MattR]

I have a 2017 and if you unplug the O2 sensors it brings up a fault on the ecu. Best way is to leave them plugged in but switched off in the ecu. No fault then.


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[Don in Lodi]

Switch off the ecu??

 

[MattR]

Switch off the ecu??

On later Gen 2s you can turn off the function of the O2 sensors in the ecu. If you remove them the ecu records a fault but if you leave them in place but switch them off the ecu ignores them


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[bimota]

my gen 1 was at cjs racing in bristol with chris on the dyno 4 yrs ago for over 4 hrs first thing he did was unplug the lambda sensors, left them in the header pipes as we did not have blanking plugs for them at the time, he cable tied them out of the way .
but now i,ve taken them out and put the blanking plugs in

rob

 

[Cantab]

On later Gen 2s you can turn off the function of the O2 sensors in the ecu. If you remove them the ecu records a fault but if you leave them in place but switch them off the ecu ignores them


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Thru the Flash.

 

[pooh and xtine]

My Dynojet map has the O2 sensors disabled by turning off adaptive learning. Even though the sensors are still connected it still threw a fault code which I had to delete with the Power Vision thingie. Euro 4 means that the warning light has to come on to alert you to the terrible environmental dangers of closed loop not operating! If that’s because it’s been disabled in the ecu it doesn’t matter if the O2 sensors are connected or not, it’ll still throw an error code.

If adaptive learning is still active in the ecu and you disconnect the O2 sensors it will throw a fault code for the same Euro 4 reason (it’ll also run poorly because it still tries to adjust the afr all over the place with very strange effects).

I have left the O2 sensors connected so that I can try different options like stock closed loop map with no decel cut and lower fan temps, for example.

 

[MattR]

my gen 1 was at cjs racing in bristol with chris on the dyno 4 yrs ago for over 4 hrs first thing he did was unplug the lambda sensors, left them in the header pipes as we did not have blanking plugs for them at the time, he cable tied them out of the way .
but now i,ve taken them out and put the blanking plugs in

rob

Yeah he told me that’s what he used to do. But the new ECU does not tolerate that.


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[randomdude]

Thought I would share this with you all, I have a 2012 ST, ecu flash, full arrow exhaust.

i was running the standard front pipes and an arrow end can I then fitted the front pipes and it was great making the engine so free but it developed the off idle judder which was so annoying in traffic that I was about to refit the standard front pipes. I did the 3/4 turn and TB balance plus clutch basket Change stll had it.

well I unplugged the O2 sensors and now have the smooth old S10 back. No error codes or warning lights and she runs as smooth as when I bought her. Now no off idle stutter and rolls smooth from tick over.

one happy owner. Just need to repack the can as it’s a bit loud now.

Andyb43, thanks for sharing this! May I ask, do you still run the same set-up and if yes, are you as happy with it? Any ill effects from keeping the O2 sensors unplugged?

Thanks in advance

 

[bimota]

got a question here for you guys that know more than me.

my bike is a gen 1, was taken 4 yrs ago to cjs racing in bristol for a 4hr dyno run and ecu flash cost me back then over £400, the bike then while this was being done had standard headers, k&n filter, and yoshi can, now he transformed the bike it runs superbly the o2 sensors were unplugged
and tied up out the way, no issues with the bike.

but the last 2 yrs keep wanting to take standard headers off and put arrow headers on, but don,t want the massive expence of another flash,

i keep telling my self thats its been flashed, i have no o2 sensors connected so i should have no issues with swopping to arrow headers

imput please guys

rob

 

[MattR]

When Chris flashed it, did the old headers have cats in? The Arrow headers don’t have cats so that would probably be a big enough change to require a reflash. But Chris does a postal service. And if you ask him to flash your ecu with the map he made for my bike which has arrow headers it might help. Postal is much cheaper.


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[bimota]

when it was on the dyno, done there matt, the oem headers did have the cat in it, still he drilled each header to get the gases right and then pluged the holes, the o2 sensors were disconected but no blanks so left in discounected.

so i have a gen 1 with oem headers, k&n filter, yoshi can it runs superb, but want to put the arrow headers on now, but i,m not going to if i have to pay for headers and another flash

rob

 

[Andyb43]

Andyb43, thanks for sharing this! May I ask, do you still run the same set-up and if yes, are you as happy with it? Any ill effects from keeping the O2 sensors unplugged?

Thanks in advance

Hi randomdude still working well stumble is now barely noticeable pops a bit on shutdown but running well, I did repack The end can so much quieter now.

 

[randomdude]

Hi randomdude still working well stumble is now barely noticeable pops a bit on shutdown but running well, I did repack The end can so much quieter now.

Hi Andyb43, good to know, thanks. My bike is also a 1st gen + Akra/K&N/flashed ECU, so I think I'll go ahead and order the Arrow headers.

Also, through my "research" on this, I found out that as long as you have the O2 sensors unplugged, you might as well want to consider adding O2 sensor eliminators, a plug n play/ 20dollar device that is supposed to enrich somewhat the fuel so you might get less popping on decel, even better smoothness, for what it's worth.

 

[MattR]

On Gen 2 2017 on and maybe before, if you disconnect the O2 sensors by unplugging, it brings up a fault on the dash. Better to switch them off in the ECU


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