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Pushr0d
| Posted on Wednesday, March 08, 2023 - 09:04 am: |
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'08 XT. This one is a puzzler. I've noticed that after a highway run of maybe an hour or so, I get a CEL when I come to a stop, or maybe it's when I close the throttle. The engine doesn't idle properly - it holds a high idle (~2000 rpm) for a bit, then comes down to normal, but uneven 1100-ish. The bike runs normally with throttle. If I turn the bike off and immediately restart it, the lamp returns fairly quickly. But if I let the bike rest for a while, the lamp doesn't return. This doesn't happen around town. Only after long-ish highway runs. I assume it's a 'heat-soak' issue. Maybe the TPS. I'd look on ECMSpy, but the code goes away, and IIRC, there was no history the last time I looked. And now, my Buelltooth dongle appears to have died. (Is Revision Motors still in business?) So - anyone have any ideas what could be going on? I have a spare TPS - I might swap it out just to see if it makes any difference. |
Zane
| Posted on Wednesday, March 08, 2023 - 11:38 am: |
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O2 sensor. They're a mild pita to replace but not a horrible job. Rather than pulling the engine like the manual says, remove the back wheel and you can access it for replacement. When you do find the answer, let us know what it was. |
Mikko
| Posted on Thursday, March 16, 2023 - 07:07 pm: |
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I had these symptoms off and on for several riding seasons. An additional clue was a significant drop in mpg/range when it happened (it would hit me in the middle of a multi-day trip and I had no choice but to keep going with the CEL lit up--then my fuel light would turn on at 110-120mi into the tank, vs. more like 140-150mi). I'm fairly sure I tracked it down to the engine temp sensor. It is located in the top of the rear cylinder, and in my case the corded cable was frayed and loose. It should be tucked in to a bracket in the frame over the top of the cylinder, but mine was loose. Under highway conditions there must have been enough airflow there to push it against the side of the cylinder head, triggering a short (or near short) that resulted in a high temp reading. This causes the ECM to light up the CEL (but not store a code) and run the FI super rich (to cool it down, but also wrecking MPG). I learned to get the light to go off by decelerating down to ~60mph but it would invariably return after speeding back up. Also, it would not happen if the ambient temperature was sufficiently low (50s). Anyway, since I fastened the cable so it can't touch the cylinder head I have not seen the issue return. It is a bit awkward to do but if you remove the airbox you should be able to reach it. This is on my 09 xb12x. Note I did not need to replace the sensor itself. |
Pushr0d
| Posted on Thursday, March 23, 2023 - 08:46 am: |
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Not a real illuminating update, but - I ordered a new Buelltooth from Revision Motors (Thanks Dave!). Hooked it up, and ECMDroid showed two Code 34's (IAC) in History. So, I dug into the bike and removed the controller. I cycled power and the plunger moved normally. Although I didn't see anything abnormal, I gave the plunger and the seating surface a good clean and put it back together. The throttle plate moved normally and looked to fully close. While I was under the airbox cover, I also checked the engine temperature sensor and wire. The sensor tested close to specification, and the wiring looked intact. I cleaned and remade the connection. No telling if I accomplished anything - again, the problem only surfaces after a lengthy ride. I'll update this post. |
Sagehawk
| Posted on Thursday, March 23, 2023 - 11:30 pm: |
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are you able to datalog? Fan still functioning normally? normal as to the proper protocol for fan that you're ecm eeprom calls for. different years, ecm's , eeproms, the bike may be just reacting normally to a high heat situation that the ecm is seeing. |
Pushr0d
| Posted on Monday, May 15, 2023 - 11:22 am: |
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Update. Rode the bike up to our property near the state line. Approximately 80 miles. Town/rural/brief Interstate miles. Bike ran great/normal until I slowed for a stop sign about 70 miles in, then CEL popped up. I had to stop and take cover from a bad thunderstorm. About 40 minutes later, started and rode the bike the last ten miles with no issue (and no CEL). Headed home the next afternoon, bike ran great all the way home. Well, until I slowed to turn into my driveway. The CEL illuminated. Hooked up ECMDroid and only code in history was 34 - IAC Circuit (P0511). The Electrical Diagnostic Manual testing doesn't apply - the IAC works great until it doesn't. And by the time I could tear into the bike to test the unit, it'd almost certainly work normally. All I can guess is some sort of 'heat soak' issue. Unless someone has better information. So - the new unit (Buell P/N p0282.5aa) is either scarce or pricey (StPHD wants $249!), or both. Anyone have a good used one, or a cheaper cross-reference? |
Smorris
| Posted on Tuesday, May 16, 2023 - 11:17 am: |
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can it be cleaned? think there was something in manual not to touch so maybe an appropriate electronic sensor cleaner would resolve(or destroy) |
Heavy18
| Posted on Tuesday, May 16, 2023 - 04:01 pm: |
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Sorry, I can't be much help, but this is a little cheaper at least: $177 after shipping eBay I can't vouch for this company but $55... might be worth a gamble: www.baboon.en Keep posting until you resolve it, threads like this that save me in the future! (Message edited by Heavy18 on May 16, 2023) (Message edited by Heavy18 on May 16, 2023) |
Tpehak
| Posted on Tuesday, May 16, 2023 - 05:16 pm: |
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What you mean CEL goes away? There is no historical codes? If so there are only few occasions when CEL turns on without storing the error code - when you turn the engine start switch on (during idle actuator zeroing process), also when engine is overheating (or when ECM believes engine is too hot and the CEL is blinking if this happens indicating skipping plugs) and also if the CEL circuit is somehow powered (by shortage for instance). If you can not read the error code with the dongle read the 2008 buell xb electrical manual or Google about how to read the error codes shortening two pins on the service plug. |
Tpehak
| Posted on Tuesday, May 16, 2023 - 05:29 pm: |
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Code 34 is IAC too low or too high (if I remember correct). It means the ECM thinks the IAC is almost or completely closed (or almost or comletely opened) and the engine RPM is still too high or too low for the throttle position sensor value when the throttle position sensor shows the lowest value (throttle is released). The are multiple reasons or combinations of reasons - throttle body air leak, throttle body flap is contaminated, contaminated and inappropriately zeroed IAC, bad IAC, bad TPS, not calibrated TPS, ECM issues, electric circuits issues, fuel delivery system issues, etc. Read 2008 Buell XB electrical manual for troubleshooting the error 34. The most common error 34 is IAC too low (idle RPM too high and IAC can not lower it anymore) and the most common reason is throttle body air leak and crappy Buell throttle body design. (Message edited by TPEHAK on May 16, 2023) |
Pushr0d
| Posted on Wednesday, May 17, 2023 - 08:49 am: |
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Tpehak, the history code I get is 34 - Circuit. And the CEL clears when the bike is turned off, then back on. I think I noticed in an earlier episode that if I continued riding, the CEL came back fairly quickly. Otherwise, like during my normal short commute, it never comes on. |
Pushr0d
| Posted on Friday, June 09, 2023 - 02:43 pm: |
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Update - It may be my imagination, but I think my idle is not steady as it used to be. I've ordered a replacement IACV from Baboon in the Netherlands. $80 shipped. I'll provide an update when I receive it, and if the new unit makes a difference. BTW, it appears Baboon has quite a lot of Buell parts. Including header pipes and seats. |
Pushr0d
| Posted on Tuesday, June 20, 2023 - 11:56 am: |
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Update - the new IACV showed up in about a week! From the Netherlands! No way to know if I've fixed the problem until I go for a lengthy ride. I'll let you know! I've got to give Baboon.EU high marks! |
Tpehak
| Posted on Thursday, June 22, 2023 - 03:08 am: |
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I am sure it is intake air leak. When the intake has air leak the air flow can be inconsistent (wobbly throttle body or oil soaked seals) and this is what causes inconsistent idle. The only proper solution to fix it once and forever is this https://www.buellxb.com/forum/showthread.php?53975 -High-performance-intake-manifold-flanges-for-2008 -2010-Buell-XB |
Pushr0d
| Posted on Tuesday, February 13, 2024 - 12:50 pm: |
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Well, finally an update! I don't get to take long-ish rides very often. This past weekend I again rode up to the 'farm' 80 miles away. And then home again. No CEL. I had replaced the ECU with a newer unit from an 1125 (same Part Number) I found on eBay. I first copied the tune from the old ECU, then loaded it into the 'new' one. Bike runs better all around, especially at idle. So - the culprit was a failing ECU. |
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