Open Loop Data Run AFR Desired Question

[Tsani]

Exactly what is being read? Is this a setting from the map I booted in or is it derived by the ECM using the data from the sensors and map? All I know is that the desires AFR was lower incertain areas than the map was set at. So I changed the map to reflect this and the bike is running a good bit better. I am trying to understand how this works and comes together. Getting bthere slowly. Gotta get those 02's installed!

[wolf_59]

Tsani, great question that I have wondered about that myself when I would set my AFR at 13.5 over the entire map and the data run would show 12.8 or whatever at times. Hopefully someone can answer

[mayor]

I'm trying to follow a long with what you're doing, but I'm not quite sure I follow.  You are running open loop, and you are adjusting the afr table to richen up the mix..this much I have.  If I understand what you are asking, you want to know just what the AFR table is tied in with, correct?  I haven't done anything with mt6 files, but I would assume that they are very similar in how they work to 7's and 8's.  The VE tables is the road map to your engine's airflow potential (volumetric effeciency), and if they are set correctly the afr tables become real values (meaning mostly accurate).  The problem with the download flash you are using is the VE tables are very likely wrong for your build, which means the desired AFR values are not correct.  This means that it is as much likely that you would have to set the desired afr to 14.6:1 (or what ever the highest is on the mt6) to reach 14:1 as you would be to set the afr table to 13:1 to reach 14:1.  The data on the AFR tables just is not real until you map your VE's (this is where the closed loop Vtune comes in). 

If it were me, I would set the afr to where I would want and use the throttle position and rpm's to tell me where to adjust the VE's.  Quite honestly, your best bet is to find a cheap dyno event that you can get wide open throttle pulls with and at least try to get some data to work with.  The other option is do a bunch of data runs and look for trends with pulled timing, since pulled timing could be too lean as well as too far advanced.  The trick with that is you need to be able trust that you are not too far advanced when you decipher your data.  If you have patience, viewing the scan data is your best bet to try to get you cal close with out hard o2 data to back up what is actually happening.  If you want to get an example of how to read the data recording and spot trends, there's some specifics covered in the thread: http://harleytechtalk.com/htt/index.php/topic,38047.100.html (read reply #107 and down) That thread is a long read, but reply #139 covers some trends that we were seeing and it helped us determine that we had an VE table (and ultimately actual afr) issue.  Even though that bike is closed loop capable, the areas that the timing was being pulled was open loop. 

hth,
mayor

[lonewolf]

I will have to dig through some data files but IIRC the only time I see a different "afr desired" than what is asked for in the map is when warmup enrichment is working.

[hrdtail78]

I will have to dig through some data files but IIRC the only time I see a different "afr desired" than what is asked for in the map is when warmup enrichment is working.

Same here except when other non steady state tables are coming into play, and PE mode.

[strokerjlk]

I will have to dig through some data files but IIRC the only time I see a different "afr desired" than what is asked for in the map is when warmup enrichment is working.

You don't see/hear it talked about much.
What about distress mode? You ever seen one running so bad that the ECU calls out for a 12.5 12.9 AFR everywhere?

[Tsani]

This is a MT8 map but still open loop for now.
So if the AFR desired is lower than the range set in the table, what direction do I take the VE's? Lower them?
I will read that thread. See what I can figure out. I can do two data runs a day, to and from work, about 70 miles each way.
I have every thing I need to do the O2 install. I take it with O2's, the afr is read directly, more or less?
I will be getting the bike tuned, but time is an issue right now. But I would still like to understand what is going on and why.

[wolf_59]

Hope this helps you understand what I believe Tsani and I are talking about
I have my AFR set at 14.6 across the board for Vtuning only thing I see in the data log is where it is pulling a little timing while this happens also notice it occasionly on decel 0% tps

[attachment removed after 60 days by system]

[mayor]

for every 20 increment increase in VE you richen the afr by 1 point, for every 20 decrement in VE you lean out the afr by 1 point.  20 increment/decrement is is 10 points on the VE tables. 

[WVULTRA]

wolf:

IMO, you might have a better understanding of what's going on if you extract your data from the recording to an excel/.csv file. 

Sounds like you may have a difference in adjacent VE cells where the ecm is reducing/increasing actual afr to compensate.  I'm also thinking that the ecm may increase afr if there's a knock retard event.

Have seen instances of afr changing from Desired/AFR Table due to first stage of EITMS, accel/decel tables in addition to WE that lonewolf mentions.

Extracting the data will show you many calculations/changes the ecm is making and will be overwhelming at first.  But definitely good reading!

[strokerjlk]

Exactly what is being read? Is this a setting from the map I booted in or is it derived by the ECM using the data from the sensors and map? All I know is that the desires AFR was lower incertain areas than the map was set at. So I changed the map to reflect this and the bike is running a good bit better. I am trying to understand how this works and comes together. Getting bthere slowly. Gotta get those 02's installed!

sorry your kinda pissing in the wind. short answer... your not collecting any AFR data. so whatever your seeing isn't anything you can base an actual decision on.
you can make ve adjustments or afr adjustments and help it out,based on seat of pants and some data runs. knowing exactly where your problems are and seeing the problem area in a data run will help you make some educated decisions. but nothing (you have current) is going to tell you what your "actual" afr is.

[Steve Cole]

This is a MT8 map but still open loop for now.
So if the AFR desired is lower than the range set in the table, what direction do I take the VE's? Lower them?
I will read that thread. See what I can figure out. I can do two data runs a day, to and from work, about 70 miles each way.
I have every thing I need to do the O2 install. I take it with O2's, the afr is read directly, more or less?
I will be getting the bike tuned, but time is an issue right now. But I would still like to understand what is going on and why.

When running an open loop calibration the value you see in the reported AFR is what the ECM is using at the time of that reported data to calculate fuel delivery with. It is not measured. The ECM calculates the AFR or Lambda based on the various sensors and what you have put in the AFR table to arrive at what you see being reported. The TTS base calibrations use both fuel and cylinder skip fire to help control idle temperatures, this is NOT done in other calibrations, so you can and will see things happening at idle when the motor is in an increased temperature condition. Once you install the O2 sensors and get into closed loop this adds another layer of input to the ECM. So the ECM will now begin to adjust on information received from the O2 sensor but the reported AFR is and will remain what is programmed into the ECM not a direct measurement of what is really there.

[wolf_59]

Tsani, did you ever get a data run to see what was going on when the desired afr changes?
My problem was knock retard would cause the desired afr to change from 14.6 to 14.5, 14.2 13.7 etc. depending on how much it was retarding the timing, which also takes it out of closed loop so no Vtune data would record during this time. Did some data runs to check knock made the adjustments and all is good
Hope this helps
Thanks for the responses

[Tsani]

Wolf -  I have a data run, but really have not dug into it yet. About an hour long.