| Author | Message | ||
     Spatten1 |
Bike: 2003 XBS At high altitudes my bike is very low on power. When open loop operation starts at 4,000 rpm: 1) Is there a set open loop mixture for all conditions OR 2) Are there a number of maps that are selected depending on where the bike was running in closed loop. I ask this question because there is no MAP sensor, so I do not understand how the fuel mixture can compensate for altitude in open loop. My bike's power loss is terrible at altitude, and I'd like to know if the bike is compensating for altitude in open loop or not. | ||
| Brewtus |
Spatten, As far as I know MAP's are learned by the bike depending on where it was run in closed loop (RPM, TPS). Altitude is then compensated by the ECM adjusting the complete fuel mixture either up or down depending on altitude. The ECM has been set up for the stock configuration only, so if you have any modifications it may not learn correctly. This is why the bike runs OK for both low and high altitude situations. Open loop is going to be dependent on where closed loop (AFV) was setteled. Hope this helps. | ||
| Blake |
Scott, Significant power loss with significant increase in altitude is unavoidable short of turbo- or supercharging. If your bike is otherwise running okay, then I'd say you are good to go. My bet is that the Buell EFI system does a very good job of compensating for altitude, even the extremes that you encounter. Sure would be great if Buell came out with a turbocharged or supercharged version. ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) | ||
| Spatten1 |
Sure would be great if Buell came out with a turbocharged or supercharged version. Yeah, how about a $500 bolt on kit...How about this afternoon! I actually started this thread in the XBoard since response was slow here. In the past I have had to do the 5 minute ride at a steady 3k rpm to get the ecm on track for current conditions. I'm just wondering what riding parameters will cause the ECM to switch to a new open loop map. If it needs the steady state riding, which cannot really be done on hilly mountain roads, or if it will adjust AFV anyway, during normal riding with constant transitions. I'd love to know the answer. The bike seems to run fine in closed loop at altitude. It is under bigger loads and rpm that it feels exceptionally flat. | ||
| Spatten1 |
Problem solved: I finally found a road at 8k feet where I could run steady state 3k for a few miles. It is like a new bike. For some reason during normal transitional riding my ECM would not adjust to altitude for open loop. The steady state ride definitely did it. Runs great during roll-ons over 4k rpm now. | ||
| Bombardier |
I have an older BMW and if I ride it at altitude I have to plug in a compensating plug. We are lucky that the new stuff does this for us. |
