There's a couple things you need to understand...

(1) the volumetric efficiency (or VE for short) needs to be set first and that can be done using the bike's narrow band sensors. The magical "14.6" or greater (assuming you're using the bike's normal sensors and not a sniffing machine) is what's needed to place the bike in "closed loop" and begin the data collection to determine the VE's.

Sniffing machines or wide band sensors generally use a lower AFR number.

(2) Once the VE's are known and set, any cell with an AFR of 14.6 or greater will try to be set to that number by the ECM (assuming a regular HD ECM).

Once the AFR in a cell is set to something less then 14.6, it will go into "open loop" and the ECM will try to provide the proper fuel based on the VE's obtained earlier. The ECM will not try to go back to 14.6 unless you're using some non-HD ECM.

Hope that helps!

 

Thanks for your reply. I'm sure it's not your intention, but this is why I get confused. That's different than how the SE smart tune works. With it, you set your lambda or AFR values and then the smart tune dials in your VE tables. Plus...others say that you are still in closed loop down to an AFR of about 14.3. Not sure what to believe.

 

When you push the smartune button it sets up the map for you for data collection. You can't adjust The "afr" it tunes at. Other devices let you make the desicion. Here is a screen shot of a "smartune" lambda table pulled back from the vci. You will also notice that the smartune drops the timing tables 4 degrees across the board. The second one is the table from the TTS set up to vtune. The SESPT sets it to lambda1 which is 14.68:1 and sets it out to 100 kpa. The TTS shows a value of .977 which equals 14.34:1 and will not you take it that lean above 90 kpa (safety feature). Once done with the data collection you can reset the lambda table as low as .977 with either device to remain in closed loop.

 

I completely understand your confusion.

First time through, the 14.6 AFR (.977 lambda) number just sets up the table so you can collect data. It's an "on/off" switching number that puts the system into closed loop. As stated above, the "smart tune" systems just do that for you.

Until the VE's are set correctly, is doubtful you'll get the AFR desired (what you typed into each cell).

But once the VE's are set, you can, if you wish, change the AFR to just about any number you want (caution advised).

Sorry for the confusion...good luck!

 

Okay...that makes much more sense. So, the "smart tune" sets the AFR to 14.6 to zero in the VE tables. Then, when you reflash the ECM, you don't check the box that says "Enable smart tune", thus setting the map back to the entered AFR of 14.3-14.4. But, now your VE tables are zeroed in and you should be getting close to the expected AFR? And, if the AFR is 14.3 or more, the O2 sensors will still give some feedback to try to maintain that AFR. Is that right? I feel like I'm slowly starting to understand a bit....

Thanks for all your help.