| Author | Message | ||
     Davo |
I am curious as to the range of AFV readings. Please list your last AFV reading. If you are stock then indicate that you are. Give a brief description of how your bike is running and the elevation above sea level where you live if the information is available. Thanks! Davo | ||
| Snowscum |
AFV=? Sorry for my stupidity! | ||
| Davo |
It is a value found on the VDSTS program. It stands for "adaptive fuel value". It is a factor that the ECM develops to use as a benchmark when the system changes from closed loop to open loop. The AFV can be helpful to tuners in order to get a window into the mind of the beast. Check out this link: http://www.sporttwin.com/Forums/viewtopic/t=1553.html | ||
| Mramsey |
XB12X, race ecm, average 1000' elevation, Odie 12 pipe exhaust valve closed all the time, airbox mod with 4 holes in the left side the same size as the 2 big holes on the right and K&N. Reset AFV to 100 always goes back to around 92 to 95. Trying to compensate for rich condition right? Bike runs good runs a little better before compensating adaptive fuel value. | ||
| Davo |
Excellent report. Thanks for the info. If there is a way to freeze AFV at then 100 you could use that on track days. Does your bike run better just after an AFV reset to 100? | ||
| Cadhopper |
06 XB12SS in Virginia, elevation 190', ceramic header, AVF 109, bike runs good at mid to full throttle, a little jumpy below 3000 rpms | ||
| Josh_cox |
It is normal, depending on elevation, air temp, etc, for a bike's AFV to move + or - 10 from 100. Even with stock parts, this happens. If you want the AFV to stay at 100, reset it, and unplug your 02 sensor. I'm pretty sure this will work just fine, only setting a DTC. | ||
| Davo |
Josh cox, I have played around with the VSS and I have had luck with freezing the stored AFV at whatever setting is stored. This still allows the closed loop operation to be normal with the O2 hooked up. I disconnected the VSS at the ECM. MPG will drop. Be very cautious with this because if your AFV numbers are low prior to disconnect then you are going to burn something up! It is my opinion that more research should be conducted before anyone tries this procedure. It is also a procedure that should be reserved for off road and testing in order to be in compliance with EPA requirements. | ||
| Mramsey |
If you want the AFV to stay at 100, reset it, and unplug your 02 sensor. I'm pretty sure this will work just fine, only setting a DTC. But then you could never enter closed loop for that great highway mileage I get of 65mpg. Can you enter closed loop with VSS disconnected? Not that I will ever do this. | ||
| Mramsey |
Davo I think you have this backward. Low AFV #s indicate your engine was running rich in closed loop not lean. ???? | ||
| Mramsey |
Sorry I think what you were saying is if the #s were low and then you didn't reset before disconnecting. | ||
| Davo |
Mramsey, That is true but if you freeze a rich indicator which calls for the ECM to make lean adjustments and then you recall that frozen value you are going to be in trouble if the engine has a lean moment going into open loop and the ECM is looking at a frozen rich AFV. The ECM continues to make lean adjustments when you are already lean. That is a bad situation because now you are leaner than of 14.7 to 1! (Message edited by davo on October 06, 2006) | ||
| Davo |
I think if I was at a track day I would want a AFV of 100 or higher to be frozen for open loop operation. | ||
| Davo |
After several resets my AFV is once again 105.3 and my ECM is bone stock. Timing 7 late to avoid pinging. 93 octane fuel with 10% ethanol though. 350' above sea level. (Message edited by davo on October 08, 2006) | ||
| Josh_cox |
The bikes do not normally stay at 100 AFV. A completely stock bike will not be 100 unless it is operated in the exact same conditions the maps were written in. I assumed they were mapped in East Troy. That is at 860 ft elevation. The elevation change alone would cause a change in the AFV as well as air density, fuel type, etc. | ||
| Davo |
Understood, the purpose of this thread is to get an idea of AFV readings as they might appear in the event of poor performance. i.e intake manifold leaks etc. | ||
| Nutsosane |
Josh cox, I think you've been performing an excellent service lately, here and ADV. I am torn about this 07 airbox/ecm "reflash" Jmhinkle has referred to. Please contact me offline via pm. Thread jack complete and reversed. NUTS | ||
| Josh_cox |
Dave, Now I catch where the thread is going. I have seen them normally over 110. Also an intake leak will usually cause a hanging (high) idle. There will be a noticeable studder/surge in off idle performance and at steady cruising speed. The easiest way to check for intake leaks is with a propane tester when the bike is at idle. Open the propane valve when the hose is by the intake gasket/ring for each side of the intake manifold. If the idle changes, you have an intake leak. Nuts, You have a PM. |
