| Author | Message | ||
     Mikellyjo |
OK, other than a snapshot of how well each cylinder is performing...what do they mean? I just recalled mine and they read 99.5 for both the front and rear. Is that a good thing? I haven't done the most current re-flash yet. If 99.5 is good, then what is bad? And what do we do if they fall into the bad category?   | ||
| Ekruizenga |
Thanks for asking this question, you beat me to it. Hopefully someone can clear this up for both of us as mine are currently 94.5/94.5 before 2nd flash. | ||
| Chevycummins |
This is my conclusion of AFV. The ecm is using the O2 sensors to monitor the mixture in closed loop operation. I think the ecm is shooting for 14.7 to 1 and if it has to add fuel to get the 14.7 then the AFV will go above 100, if it has to remove fuel then the AFV will go under 100. This change will be applied to open and closed loop operation through the entire RPM range. This is just how I understand AFV and I may be wrong. Seems like a tool to help with diagnosis of a problem. | ||
| Zac4mac |
That's pretty much how I see it too Mike. Therein lies the indirect tie to altitude. At 5000' ASL, Loretta is happiest at ~ 95/95. At those numbers, she was VERY rough at sea level. The new flash should change these numbers. Z (Message edited by zac4mac on September 23, 2008) | ||
| Jpfive |
That is my understanding also, Chevy. It is important to realize that this is not a correction for altitude, however, as this is done independently through a separate table, which is a matrix of barostat and temperature inputs (calculating density altitude). I remember this as being pretty well established in an earlier thread, which was contributed to by one of the anonys. My AFV's do not vary at all with altitude, verified by the readings I took on my last mountain trip. Jack | ||
| Mikellyjo |
Makes complete sense...in a "why didn't I pay more attention in school" sort of way. Thanks for the clarification...it appears then, in order to change to values we are at the mercy of an ECM flash and the computer. Not that I would want to, but I guess long are the days of swapping out jets...sigh. | ||
| Eaton_corners |
I have also been wondering about AFV's as mine have been at 105/110 before and after the latest reflash. If this is an indication of rich or lean similar to jetting on carburetors then mine has been running rich all the time. My MPG is higher than most others on BadWeb but that could be riding style. I am at 795 ft. above sea level. | ||
| Velocity |
Hey how are you getting to your AFV numbers. Even my dealer could not help. Scott | ||
| Chevycummins |
While you turn the key on hold down the toggle and mode buttons and that will put it in diagnosis mode. Then push the lower button and it will take you through codes and data and to AFV. | ||
| Jmr1283 |
press both the toggle and mode button as u turn ur key on and itll say diag codes or something like that. then go through all the stuff like voltages and stuff to front afv then after that rear afv. i think u press the toggle button to scroll through to the afv. or maybe its the mode button | ||
| Mikellyjo |
What Chevy said...and make sure your security setting is off. At least I had to turn mine off because it kept trying to set the pin. | ||
| Velocity |
Ok, that was it , mine kept trying to set the pin. Dealer sent me home to read owners manual. I found it thanks! Scott | ||
| Xb9 |
"then mine has been running rich all the time." That's not quite right. Eaton_corners, on your bike the ECM has determined (through O2 sensor feedback data) that your bike was running generally lean with the base starting AFV values of 100/100. Based on the feedback, it has adjusted your overall A/F ratio 5% richer on the front and 10% richer on the rear to dial it in to the target A/F ratio, which is usually 14.7 to 1. Once it has made the adjustments, you are as close to ideal (not rich or lean) as you can be. It mainly affects open loop operation and not so much closed loop operation where the ECM uses the O2 feedback real time to adjust. All this means is your particular engine wants a little more fuel than what the base AFV's were giving it. Some engines require less, some more as no two are the same. I used to hear that +/-5% is ideal, but only Buell would really know what the design limits would dictate as acceptable. Looking at all the 1125R data that everyone has posted, it may be +/-10%. | ||
| Eaton_corners |
Thanks, that makes sense as my bike has always had good performance and an overly rich fuel mixture would have surely shown itself. | ||
| Mikellyjo |
Well I thought I had a handle on it. So your saying that my particular 25r, after all the inputs from various sensors, needed an AFV of 99.5 for front and rear to get to the magic number of 14.7:1. That I can accept. But, at what point can we say something is wrong...other that the bike is obviously running like a bag of smashed A$$. I prefer seat of the pants tuning myself...but surely this info is on the diagnostic menu for a reason other than confirming what AFV the computer is telling me the bike is running at. | ||
| Edmbueller |
Ok I am trying to understand this. I was holding back from buying a Jardine because I did not want to lean out the motor too much. Does this then mean that the bike will automatically adjust so that it does not run rich or lean? | ||
| Xbswede |
Yes and no. If you get an aftermarket exhaust the bike will re-learn so it does not run lean at cruising speeds and then apply that new percentage to WOT. The problem is that after market exhaust do not flow exactly linear as the throttle is opened up. Some are higher flowing on the top end others down low. This will cause a AFV that is not optimum because the ECM is based on the flow of the stock exhaust. At least that's how I understand it. | ||
| Xb9 |
+1 Altering the exhaust without matching the fuel mapping is only doing half the job. | ||
| Xl1200r |
Correct - The new exhaust will force the ECM to relearn, but the changes will only by "optimum" for a relatively small RPM range and throttle setting. Outside of that, the fueling could be off. However, on a dyno, the Jardine HP and TQ lines seem to follow the stock lines nearly exactly (no more than a 2 point deviation in either curve), so I would bet that you woudln't have problems with that pipe. We should expect a dyno run with AFV readouts with the Jardine from Hitman this weekend to confirm. | ||
| Hitman44139 |
We should expect a dyno run with AFV readouts with the Jardine from Hitman this weekend to confirm. I have a Dyno appointment on Tuesday. I will post video and sound clip ....like I said this weekend. Unless of course I dont get my bike back. But I have all the confidence in my dealership of getting done by Friday. | ||
| Hitman44139 |
My stock exhaust will go back on if the dyno results are not up to par. | ||
| Xb9 |
Best practice after the stock muffler dyno run would be to have the dealer reset the AFV's to 100/100 when the Jardine is installed to start from the same baseline. Then ride the bike in various RPM conditions (normal) for a period of time after the Jardine is installed - enough to allow the ECM time to adjust the AFV's. Then Dyno it with the Jardine. Just throwing it on the dyno with the stock muffler's AFV's and seeing what it does would skew the analysis IMHO. | ||
| Mikellyjo |
But...per the direction this thread was going. The computer controls the AFV based on trying to achieve 14.7:1 ration. You are saying that we (the dealer) can actually over ride the computer? Is that something that the ECM spy software does? | ||
| Xl1200r |
Can't override, just reset. On the bike, you can rest to 100. On ECMSpy you can set them to whatever you like (I think), but the ECM will adjust as needed after that (I think). | ||
| Mikellyjo |
HA! Like trying watch Monday Night Football when a chick flick is on...you can change the channel all you want, but it still gets "adjusted" to "When Harry Met Sally!" | ||
| Ponti1 |
HA! Like trying watch Monday Night Football when a chick flick is on...you can change the channel all you want, but it still gets "adjusted" to "When Harry Met Sally!" I think your remote control is defective! Mine locks in MNF and holds it there, even for OT... | ||
| Kalali |
"...On ECMSpy you can set them to whatever you like (I think), but the ECM will adjust as needed after that (I think)" On ECMSPY you can define a lower and an upper bound for the AFV value. You can "force" the AFV to stay at a specific number by setting both of the limits to that number, e.g.,100. | ||
| Boltrider |
On ECMSPY you can define a lower and an upper bound for the AFV value. You can "force" the AFV to stay at a specific number by setting both of the limits to that number, e.g.,100 That must be how people using ECMSPY get away with locked AFV's without disconnecting the O2 sensor. (Message edited by boltrider on October 01, 2008) | ||
| Fresnobuell |
Okay all you smart guys. my AFV for the front is 85 and the rear is 94.5. I am about 250 feet above sea level. According to what I can gather, this means that the mixture is being leaned out by the ecm. Correct? 1) Are people finding similar figures after the flash? 2) Is it strange that the 2 figures are so different? | ||
| Chevycummins |
After the flash my AFV went from 99.5 to 100 and seems to be staying there. Runs great now. That does seem like a big difference front to rear. Does it run ok? If it does I would not worry about it too much and continue to monitor the AFV. Yes the ecm is removing more fuel from the front cyl map. Was anything else touched on the bike at the time the flash was done? |
