submax
Well-known member
Hi all,
I've spent a good amount of time during the past few years going through my 2009 XB12Ss. I replaced the exhaust header with a new OEM one, installed Drummer SS and matching ECM from IDS. The bike already had a K&N filter and breather reroute (poorly done, so I redid it). New battery, new O2 sensor. Anyhow, the bike was running tip-top this summer. Then, a few weeks ago, it started surging around 3k rpm (it had done that before all my work, but not since then). I did a TPS reset and that seemed to help, but I contacted IDS and asked what they thought. I spoke with Tim and I learned a lot in exchanging emails with him.
According to Tim, the ECM continually adjusts the TPS zero position each time you ride, making small changes as necessary. As long as nothing changes dramatically, like the sensor being replaced or rotated on its mount, the TPS should not need to be reset on a regular basis. He thought that the surging was likely due to an abnormally-low LFuel value (also known as the Adaptive Fuel Value). The ECM adjusts this global fuel correction value as you ride, especially in the cruising region of the map. If this portion of the fuel map is not calibrated exactly right, the LFuel value can drift.
Additionally, I asked Tim about why it seems like getting the fuel mapping right on Buell XB's is particularly challenging as there have been many posts over the years with owners reporting surging issues. He said that surging can be a result of many different issues, some calibration related, others not. He said that the XB12 is based on the Sportster engine but delivers significantly more power...a big reason for this being cam timing and lift. There’s quite a bit of valve overlap, so when the engine is at half its rated speed and very light throttle, cycle-to-cycle combustion repeatability is poor. The folks at IDS have various EFI features and functions to address this inherent instability, but it takes time and experience to get it right.
Finally, Tim told me that they had just finished developing a new mapping specifically for 08-09 XB12 with Drummer SS exhaust due to customers reporting issues. He generously offered to update my mapping free of charge. I sent it in at the beginning of September and got it back within a week. I've been running it since then and so far it is running great with no surging issues. I'll keep you all posted if the surging returns. But, either way, I wanted to give a shout out to Tim and the folks at IDS for their excellent customer service. :up:
I've spent a good amount of time during the past few years going through my 2009 XB12Ss. I replaced the exhaust header with a new OEM one, installed Drummer SS and matching ECM from IDS. The bike already had a K&N filter and breather reroute (poorly done, so I redid it). New battery, new O2 sensor. Anyhow, the bike was running tip-top this summer. Then, a few weeks ago, it started surging around 3k rpm (it had done that before all my work, but not since then). I did a TPS reset and that seemed to help, but I contacted IDS and asked what they thought. I spoke with Tim and I learned a lot in exchanging emails with him.
According to Tim, the ECM continually adjusts the TPS zero position each time you ride, making small changes as necessary. As long as nothing changes dramatically, like the sensor being replaced or rotated on its mount, the TPS should not need to be reset on a regular basis. He thought that the surging was likely due to an abnormally-low LFuel value (also known as the Adaptive Fuel Value). The ECM adjusts this global fuel correction value as you ride, especially in the cruising region of the map. If this portion of the fuel map is not calibrated exactly right, the LFuel value can drift.
Additionally, I asked Tim about why it seems like getting the fuel mapping right on Buell XB's is particularly challenging as there have been many posts over the years with owners reporting surging issues. He said that surging can be a result of many different issues, some calibration related, others not. He said that the XB12 is based on the Sportster engine but delivers significantly more power...a big reason for this being cam timing and lift. There’s quite a bit of valve overlap, so when the engine is at half its rated speed and very light throttle, cycle-to-cycle combustion repeatability is poor. The folks at IDS have various EFI features and functions to address this inherent instability, but it takes time and experience to get it right.
Finally, Tim told me that they had just finished developing a new mapping specifically for 08-09 XB12 with Drummer SS exhaust due to customers reporting issues. He generously offered to update my mapping free of charge. I sent it in at the beginning of September and got it back within a week. I've been running it since then and so far it is running great with no surging issues. I'll keep you all posted if the surging returns. But, either way, I wanted to give a shout out to Tim and the folks at IDS for their excellent customer service. :up:
