| Author | Message | ||
     Chessm |
on saturday morning i was charging aggressively uphill on a twisty road (north on 35, right after Alice's and 84 in the santa cruz mountains) and the bike seemed to lose power. i thought i was lugging it at first so i downshifted, and the bike just revved a little more but still very down on power. i slowed down for a bit and it seemed to clear up after a while. next morning on sunday, i was on the same road going the same way, riding a little harder this time and the bike did the same thing. except it did it for longer this time. the bike is a bonestock 04 xb9s (but its got 03 parts all over it for some reason). both morning i had been riding aggressively in that area for the about 2 hours previous. also the bike had never done anything like that before or since. i tried searching, but i mightve been using the wrong keywords, elevation, change, power, fuel, and combinations of. | ||
| U4euh |
Chess, does your check engine come on to give you any idea that it is something the bike may monitor? Everytime I go to March Badness, or up to the hills of NC, my bike will do the same thing, only kind of a burp,fart, then runs like a bat outta hell. I suspect my problem is something to do with IAT or O2 sensor and the computer getting stuck in a loop. Been that way since I got it, and the dealer has hooked up the computer and could never find a code. The TPS has been reset, O2 sensor replaced, and still does it!!!? | ||
| 07xb12scg |
on saturday morning i was charging aggressively uphill on a twisty road (north on 35, right after Alice's and 84 in the santa cruz mountains) and the bike seemed to lose power. As you probably know, you are going to make less power at higher elevations. Going uphill probably made things feel much worse. | ||
| Punkid8888 |
another thing is, I beleive the relearn squence will also help for elevation changes. If you can find a straight section mid way through the ride. cruise it at about 3500 for a few miles in a high gear. The computer will recalibrate and hopefully give you some more power. just a thought | ||
| Chessm |
hmmm the bike rode fine when i went the other way on that same road earlier in the morning. that time i also went uphill towards the peak but i rode more sedately and i didnt experience any problems. oh well, i guess this just means i cant go chasing sportbikes uphill  | ||
| Spatten1 |
If you can find a straight section mid way through the ride. cruise it at about 3500 for a few miles in a high gear. The computer will recalibrate and hopefully give you some more power. Yes, but I think it is 3000 to 3500 rpm. Chessm: It is a problem. It is not you. The XB's apparantly do not adjust for altitude unless you can do a long steady cruise at 3k to 4k rpm. If you are sport riding through elevation changes the FI will not adjust and the bike will run like it is dragging an anchor. It stays way too rich for the altitude in open loop. Try to just cruise at steady throttle for a few minutes in the right rpm range and the bike should "learn" from successive rich O2 toggles. The mileage is great on XBs in closed loop cruise, but performance in changing conditions is way behind those "primitive" open loop systems, if you don't get the ECM into learn mode. There are long threads on this somewhere. Al at American Sportbike has the tech info you need to learn how to get your ECM to learn. I don't think the guys with 12s feel it as much, but I also ride a 9, and it is very obvious that it is not adjusting for altitude. I've incorporated much more steady state throttle into my riding and it seems to help quite a bit. (Message edited by spatten1 on June 25, 2007) | ||
| Chessm |
a guy on a ducati 1098 got away from me because of this  k, thanks for the advice, yawl! | ||
| Chainsaw |
My first guess is you have a sensor going bad, O2, MAP or something. I routinely run elevation changes of 3000-4000 feet in a matter of 30 minutes or less. I don't recall ever having a problem like you're describing. It takes an altitude of 10,000 to 12,000 feet before I notice a significant power loss. | ||
| Ft_bstrd |
Would running richer as he heads higher decrease power? Would the air temperature sensor create a problem? As he heads higher the air would be cooler. Would there be a delay in the ECM accomodation for the cooler air? | ||
| Spatten1 |
Chainsaw: If you ride in closed loop up the mountain it should adjust fine. I find the problems when I stay above 4k, WFO, and use constant throttle transitions while making altitude changes. It does not seem to adjust then. | ||
| Cycleaddict |
higher elevations =thinner air + (less oxygen) same amout of fuel =rich a/f ratio. when our f/i computer "learns" new conditions does "it" store this info for future use , or does it throw it away & have to re-learn everytime ? | ||
| Spatten1 |
My understanding is that it essentially throws it away. Since there is no MAP sensor it cannot "jump" back to previous experience at that altitude (air pressure) and temperature. It has to update the A/F value through closed loop operation at each new altitude. It adjusts to current conditions using feedback from the O2, but only at certain RPMs in closed loop. Problem is, if you are running high RPM and changing loads it will not update the map for the current conditions. If you can run closed loop for a while it will update. That said, chasing a Ducati up the mountain will not allow the system to update, so you go richer and richer. At least that is how I read what little tech material we have, and how my bike behaves in the mountains. |
