| Author | Message | ||
     Polishblood |
Hello, I have a 2008 Buell Xb9sx with over 12k miles. Other than K&N air filter, the bike is stock. No check engine lights, no trouble codes. I am using buelltooth to read the ECM. I bought the bike 2 years ago. Before me, the owner had the bike sitting in a portable shed near Boston, MA. So it probably experienced cold temperatures. Since I bought the bike, I have had a very noticeable hesitation in power between 4-4.5krpm when the bike is warmed up. Along with this hesitation, I have a few other smaller symptoms which are not noticeable unless you owned the bike. These symptoms are strong gas smell when parking after a ride, idle sway between 1-1.2krpm after cold start for 10 seconds, and barely noticeable bucking when cursing between 2-4krpm. I recently changed the spark plugs from NGK DCPR9EIX to the OEM 10R12X (part number 27794-08). They made a difference. The occurrence of the 4-4.5krpm hesitation is significantly reduced. The hesitation use to happen 80-90% of the time now it occurs only 5-15% of the time. Smaller symptoms (bucking and smell of gas) still occur. Also the AFV changed from 82% to 90% (I ride at 150 feet above sea level). I think the possible diagnosis is either faulty oxygen sensor or faulty fuel injector/o-rings. I am leaning toward the faulty fuel injector because when replacing the spark plugs, they looked relatively good (look at atttached pictures. Left plug in both pictures is front, right plug in both pictures is rear). I did the service manual injector leaking test (build fuel pressure by turning ignition on and off 5 times consecutively). I looked at the injectors with a mirror through the throttle body and they look dry. Still I think it's the injectors/o-rings because the hesitation only occurs once the bike is warm and I performed the leak test when the bike was cold. I will repeat the test when the bike is warm in the near future. Questions: Do I need to take out the throttle body to replace the injectors? Any general advice on replacing the injectors? What do you guys think could also be the diagnosis? Any quick checks? I am very new to buelltooth, perhaps you guys can recommend me some good electronic tests. Thank you!   (Message edited by Polishblood on May 23, 2020) (Message edited by Polishblood on May 23, 2020) (Message edited by Polishblood on May 23, 2020) | ||
| D_adams |
I'd check for an intake leak at the seals. Sounds more like a very small leak to me rather than injectors, although with a 12 year old bike, it's possible. | ||
| Starbellied_sneetch |
I had similar problems with my '08 XB12 not running right (see the thread 2 below yours!). I figured I'd send the injectors out for cleaning. Well, you have to remove the intake manifold to get to the injectors, and when I removed it, there were signs that the seals had been leaking. I just got an email from the fuel injector cleaning service that stated essentially that my injectors were perfect, and whatever problems I had weren't caused by the injectors. Long story short: Change your intake manifold seals. | ||
| Polishblood |
Thanks for the replies. An AFV of 90 "should mean" my bike is compensating for a rich mixture, especially since I am at sea level. Using buelltooth, I changed my AFV to 100, along with the minimum and maximum to 100, and the bike rode smoother during closed loop with ZERO hesitation at 4-4.5krpm. However, after changing the AFV to 96, 93, 90, the bike was the most rev happy/pulled the hardest during closed loop at an AFV of 90, despite having a higher occurrence of the hesitation. The lower I set my AFV, the higher occurrence of the hesitation. Wouldn't my AFV be above 100 if my intake seals were leaking? It's currently at 90. Either way, I will be changing the intake seals along with the injectors. Just waiting for them to arrive in the mail. Today I will be changing the oxygen sensor. Thank you again for the replies. Please continue to keep the thoughts coming. | ||
| Firemanjim |
As Polishblood said, an AFV below 100 means you are experiencing a rich condition, and at 82 you had a pretty rich area in the Learned Fuel area of the map and the ecu was pulling 18% fuel across the entire map. Definitely cause a hesitation. Is the ecu stock? If so really the only thing that will add fuel is a engine temp sensor going or the O2 sensor failing. | ||
| Polishblood |
Firemanjim, I am pretty sure the ECU is stock. How do I check? I am using buelltooth. Is there a way to check the Engine Temperature Sensor? What socket is needed? I see previous posts are referring to an oxygen sensor socket but that's 7/8", the manual calls for SNAP-ON M3503B which is 1/2". I changed the oxygen sensor yesterday. Went out for a 40 minute ride, didn't feel the 4-4.5krpm hesitation but the bike didn't feel as snappy as normal (during closed and open loop rpm ranges). Perhaps it was the 100% humidity. Checked the AFV, it was 90%. I will have to ride some more to conclude whether the oxygen sensor truly helped out or not. By the way, to remove the oxygen sensor I used a normal oxygen sensor deep socket and turned the socket with a 1" flat wrench from the rear of the bike, where the shock is normally located (had like 30 degrees to turn the wrench). Then used a piece of wood to reach the wrench and striked the wood with a hammer. Worked well. No heating or penetrating lubricant. | ||
| Polishblood |
Replaced the fuel injectors and intake seals. Bike runs much better. 2-3k is noticeably smoother and haven't experience any 4-4.5krpm hesitate after 100 miles. I will ride again this weekend, write up an entire report, and confirm the hesitation is gone. Replacing the intake seals and fuel injectors was not as hard as many have described. Everything took me 8 hours but that includes, cleaning and polishing. I also have a lot of different wrenches which helped out a lot. |
