As I continue my quest for a better understanding of home tuning, I have a question. I've reflashed my 2011 RKC using a SEPST and a standard map from the SE software CD. This map has an AFR of 14.3-14.4 in most cells. So, does that mean my O2 sensors aren't doing anything? I've read that the O2 sensors only work with an AFR of 14.6. So, with an AFR set at less than 14.6, the ECM is just going off the VE tables and have no input from the O2 sensors? Do I have that correct?

If so, then basically once you have your VE tables zeroed in, in theory (not that I would) you could remove your O2 sensors?

 

I'm not sure about the SEPST but on a TTS a lambda value of .977 (equivalent to 14.3 a/f with straight gasoline) is the richest you can go while still being in closed loop, using the O2 sensors as feedback. Drop it down to 14.2 and it will not use any of the info provided by the O2's.

 

Sespt is the same as the TTS in that respect. That is a lambda calibration so there isn't any clb tables. Anything in bold is in closed loop. If it is displayed as an afr table it just shows what the lambda value would be as an afr map with the clb tables adjusted.

 

So the O2 sensors work down to an AFR of 14.3?

 

Almost, they will probably work down to 14.2 in an afr based calibration. You are using a lambda calibration so it will be out of closed loop at a .976. When you are viewing it as an afr table it is just converting the lambda values for you and rounding off the number. The lowest lambda value that will keep you in closed loop is .977. The actual afr conversion is 14.34

 

Get some back-round info about EFI in general and HD EFI in particular. Your search bar is your friend.
There are many threads on the subject here and there's also a website called Nightrider that explains the various HD EFI's.
Then read, read, read.

 

Been reading tons...seems to be lots of conflicting posts. Some say the O2 sensors only work at an AFR of 14.6, others say down to 14.2-14.3. So, thought I'd just ask one more time. Thanks for your help.

 

You can bank on the info that Lonewolf176 gives you. He is one of the best tuners out there. He helped me a lot with my questions on tuners and dyno operators.

 

Good to know...thank you.

So...one follow-up question that I can't seem to find a straight-forward answer to. Will the O2 sensors attempt to maintain whatever AFR is that you've loaded in your map? In other words, if your map sets the AFR values to 14.3-14.4, will the O2 sensors adjust the A/F mix to maintain an AFR of 14.3-14.4, or will the O2 sensors always be trying to lean out the engine back to 14.6?

 

I can't answer that, it's beyond my knowledge. All I know when I had my bike tuned with the TTS...the dyno tuner told me that he disconects the 02 sensors. I believe you cna do it either way...but I had to go by the recomendations of what he does for a living. As far as results...it was beyond my imagination. Yes it pulls a lot better but it just cruises so much smoother. I honestly don't want it any faster then it is now. With just the 2-1 pipes, the big sucker A/C and the tune it now puts out 79.64 hp and 92 t.