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Jmk015
Posted on Friday, August 25, 2017 - 12:30 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I have a 2006 Ulysses XB12Xt with 26,000 miles on it. It has started to buck and surge when it gets hot. It progressively gets worse until the bucking gets so bad that the bike is hard to ride.

It only does this in closed loop mode. If I use ECMspy to disable the O2 sensor and closed loop, it runs GREAT.

The bike has new O2 sensor (Bosch), spark plugs, plug wires, coil, and cam position sensor. The head temp sensor and IAT sensor both test OK and give accurate readings in ECMspy.

Both cylinders have good compression and the bike has no intake or exhaust leaks.

The bike has fresh 93 octane fuel.

The bike is completely stock: stock air box, stock air filter, stock exhaust, stock ECM with stock tune.

I reset the TPS and the AFV. It made no difference. The bike still runs GREAT in open loop and surges an bucks in closed loop.

The surging and bucking get worse as the temperature increases and are also much worse under load (going up a hill, or with heavy luggage).

I'm at my wits end with this! Does anyone have any suggestions to fix this issue?

(Message edited by jmk015 on August 25, 2017)
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Teeps
Posted on Friday, August 25, 2017 - 03:22 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Cracked solder joints on the ECM PCB?

http://www.badweatherbikers.com/buell/messages/142 838/809483.html?1500137318
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Jmk015
Posted on Saturday, August 26, 2017 - 11:37 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

My ECM does not have the external cracks in the epoxy, but i guess it's worth popping it open to take a look.

How do you open the ECM box, it looks like its sealed up tight?
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Greg_e
Posted on Sunday, August 27, 2017 - 10:13 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The ECM is molded/glued together, so you need to cut it open. Should be a black silicone potting compound inside, not epoxy.

I'd look at the wiring between o2 and ECM before cutting it open, and also check the values on the o2 as it is running, might need to log it. The fact that it runs OK when the o2 is disabled suggests that's where your problem is located.

After checking the other things, then it would be time to cut the ECM open, bad solder joints have become known to be a problem. The connectors take a lot of stress on some of the models and crack the joints. Don't bother looking for a cracked joint, get some good electronics grade solder (not the Lowes/homedepot junk) and a decent iron, just heat each joint until the solder flows and add a small amount of fresh solder. Look out for solder bridges when doing this.
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Greg_e
Posted on Sunday, August 27, 2017 - 10:15 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Scrap that. I just saw that you have an X. If you haven't done the ECM relocation mod, the problem is most likely cracked solder on the ECM. Search for the mod so after the ECM is fixed you can move it so it won't happen again.
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Jmk015
Posted on Sunday, August 27, 2017 - 10:22 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I just opened the ECM. A few of the solder joints were cracked, so I re-soldered them.

The bike runs exactly the same as before, great when cols but surges when hot.

Any other suggestions?
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Teeps
Posted on Sunday, August 27, 2017 - 10:42 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Intake manifold leaking?
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Jmk015
Posted on Sunday, August 27, 2017 - 11:43 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

No intake manifold leak we can find. It surges in open AND closed loop. I've attached a video below showing what it's doing; the bikes is full throttle the entire time in this video and cycles. It is almost acting like it's losing electrical power/spark.

https://www.youtube.com/watch?v=1oNeyafrqZ4
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Greg_e
Posted on Sunday, August 27, 2017 - 03:30 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Losing spark might be the pickup on the end of the camshaft.

Did you solder all of them? I tore one apart and found a few that sheared the solder so cleanly that it was difficult to see the problem.
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Teeps
Posted on Sunday, August 27, 2017 - 03:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Fuel pressure?
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Bradyd
Posted on Sunday, August 27, 2017 - 04:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hi there. I've been working with jmk015 to figure this out. Just figured it out:

http://www.youtube.com/watch?v=BHP8o6eqVck&t=0m45s

Losing fuel pressure.
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Teeps
Posted on Sunday, August 27, 2017 - 04:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Cool!
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Hugie03flhr
Posted on Tuesday, September 26, 2017 - 09:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

So what caused the fuel pressure drop? Cracked line, bad pump?
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