AFV stays 100%

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Jurrien

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Nov 18, 2018
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Hi,

I am in the process of building my xb12s back to the stock exhaust. I have got the exhaust valve actuator moving again. It turns out it was still functional but only disabled in the ECM.
So now the next thing I wanted to do is to know what my AFV is. I have never looked at it before. Yesterday I took the bike out for a ride and looked at the AFV value a few times, but it was always exactly 100%. I suspected this is due to a setting so I opened two instances of ECMspy to compare two EEPROMs: my own and that of a stock xb12.
A mayor difference I noticed is on the page '02 Setup - Closed Loop - Limits - Minimum RPM'. At the stock EEPROM this value is set to 600; on my own EEPROM it is set to 12750.
Questions:
1. Is this the reason my AFV stays 100%? Unfortunately I cannot test this because my test ride ended with an empty battery :( :( I first have to fix the charging system.
2. Why would anyone of the previous owners of my bike set this value to 12750? Is this to disable closed loop? Why? Does this indicate there are more changes to look out for?
 
1) Most likely, but it's also perfectly normal to be at 100.
2) To stop the ECM from adjusting itself during part throttle operation.Yes. Poor ideology. Probably.

The other thing to check is the AFV limits settings (and sometimes EGO). People also cheat closed loop by setting both the high and low AFV limits to 100. Since you have a stock program available, why not just use that one? (Check firmware version please)
 
Ok thanks, clear. I have not used the standard program because I do not know the exact source. I do now have a requested EEPROM from rev-mo.com and I read that it is a reliable source, so I think I will use that one.
 
Hi Jurrien,
I have a xb12r 2004 model which I have owned for 12 months.
I checked my settings in ecmspy and my O2 setup closed loop limit for minimum RPM is also set at 12750.
When I checked the EEPROM offset (which is 28, second row, 4th from the right) the value is set to ff which is the highest value, hence both our systems showing 12750.
The default value is 0c (which equates to 600rpm) I don't have any history on my bike, however ecmspy shows the ECM Mfg. Date as 6/18/2010 so it is not the original ECM for this bike.
Did you test changing your setting back to 600rpm?
 
Depends on what you are hoping to accomplish.

If you are trying to re-enable CL operation on an unknown ECM fuel map, the easiest thing to do is install a known OE program from the source KZ linked. That will undo any mods your program has.

If you want to try to find all the ways yours was modified, good luck, who knows, and don't forget to tripe check the AF ratio target table.
 
Thanks Cooter,
I have an original fuel map for a 2004 XB12r. I was going to give it a try.
I like the idea of CL mode and having the ECM learn, I can't see any advantage in disabling that function. I guess, with it disabled, you can force 13.x AFR all the time (assuming your map is good) However, I replaced the muffler that was on the bike when I purchased it (which was too loud) with a new slipon that has baffles, so the map that was on the bike will be wrong now anyway.
I have no idea what else has been done, other than the ECM was replaced and it has a K&N air filter. There were paint dots on the cams ( I had to replace the oil pump drive, so had to rotate the engine and pull the cams out) I assume the cams are original, but who knows what has been done to it over the years.
 
IMO, go full OE tune and disable the AMC... it will run fine with a slip on.

Or trash it all and get the 'race tune' from Buellmods.com or sport for a Buelltooth from Rev-mo to accomplish the same thing MUCH easier.

I agree disabling the CL function is a big step backwards, there's absolutely NO reason to run anything but a stoic target in CL*.

*simplification warning
 
I was poking around on the Rev-mo site and they have this section which explains why some people choose to dissable closed loop.
https://www.rev-mo.com/openloop
I did not see a barometric pressure gauge on my bike (did not have a close look however) but when I live, the highest elevation is 1000mtrs and that is a few hours away, most areas are only 100mtrs above sea level or less so air pressure will not change that much.
I will do some logging and see how close or far out of wack the AFR is.
 
You don't have one, unless it was added by someone. It would be left side of the battery little black round thing plugged into the 3-wire triangular connector and a short ground wire.

IMO, it would be BETTER to remove the FI and put on a carburetor than removing CL from any ECM. At least the carb will self-adjust for some atmospheric conditions where the now-hobbled ECM will not. There is NO REASON to run anything other than stoic targets in CL*

*simplification warning
 
OK. Bump my own thread. After allmost a year.
I reset all the ECM settings to the original settings and I loaded a fuel map from rev-mo.com, the "Race Tune for Stock Exhaust". This seemed like a good starting point.
Thanks to being busy with all kinds of other things, I only got around to taking the Buell for a first ride with the new settings today. I have now also tried to log the data for the first time with ecmdroid and my buelltooth stick. Once home I installed megalogviewer and viewed the data. This is all new to me but it's cool that it can be done this way.
What I don't understand yet is that I have logged about half an hour and it seems that I only see two minutes in the graph.
Anyway, I was most curious whether that AFV value would change now. It did, and I wonder what this says about the condition of the engine. According to the graph, it started at 100, changed to 95, then changed again to 100 and then changed to 105.3. Is this normal behavior for the AFV?

BuellAFVscreenshot.png
 
Not exactly, that 12750 value was for '02 Setup - Closed Loop - Limits - Minimum RPM'. For me it is now back to 600, as it should be originally.
I expected the AFV to be adjusted in smaller steps, for example per 1 instead of per 5. That's why I asked here.
 
The ECM is taking cumulative data for a fixed time frame (number of steps*) then calculating and applying that adjustment percent (AFV) directly to the fuel map to reach the targets* desired. Whatever answer that is... is applied at that prescribed number of steps. Whether thats 1 or 5 or 10* etc.

Yours is working as it was intended.

* all adjustable.
 
Thanks for all the support here from this forum. So much information to find. I've learned a lot lately about ECM and logging with buelltooth and editing settings from ecmspy and and. Never done this kind of thing on motorcycles but it is very interesting. And it makes me like my xb even more.

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