| Author |
Message |
    
Ingablodget
| | Posted on Tuesday, September 15, 2009 - 04:29 pm: | 
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I'm stuck on this one and would appreciate any help.
2003 XB9S, 14k miles, all original / no aftermarket parts.
During normal riding, engine power suddenly dropped a little, with a slight increase in vibration, but no warning light. The front plug was normal (tan) but the rear plug was white. ECMspy showed no error codes. Replaced plugs, rear injector and both injectors o-rings. Now have two problems;
1. getting error code "O2 sensor always lean". If the code is cleared, it does not return at idle but re-appears after the bike is ridden (1 mile).
2. after prolonged idle (1000 rpm, 5 minutes, 160 degrees C), revs will suddenly increase then decrease until stall. this coincides with a change from open loop to closed loop. I read that it should only go into closed loop between 1500 and 3500 rpm.
Thanks for any advice. |
Blake
| | Posted on Tuesday, September 15, 2009 - 06:21 pm: |
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Always lean may be due to short or open circuit in the O2 sensor wiring. Or maybe a bad O2 sensor.
Check voltage at O2 sensor leads at ECM, if zero, then you have identified a short to ground or an open circuit (broken connection or wire). If voltage is within expected operational range, then maybe the sensor function is questionable.
Other sensors to check include the intake air temp sensor and head temp sensor.
If none of that turns up the gremlin, then possibly the fuel pump.
I bet a good technician will be able to find the cause of the problem in short order. Those computer dealios do come in handy sometimes. |
Fahren
| | Posted on Wednesday, September 16, 2009 - 09:24 am: |
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Blake, are you talking about the black box dealios that always show up in the service manual when you are going through a diagnostic check? They do indeed look handy!
I suppose the other option is that the rear actually is running always lean, i.e., that you have perhaps an intake leak? I had the same error code show up, did the propane intake leak test, but found nothing, so I had to keep looking - turned out it was loose wiring connections. But the leak check at least can pinpoint that or eliminate that as an option.
The service manual has a great flow chart for diagnosing this trouble code.... around 3 pages of things to check, in a very systematic way.
(Message edited by fahren on September 16, 2009) |
Kalali
| | Posted on Wednesday, September 16, 2009 - 11:09 am: |
|
I had the same error code and a new O2 sensor solved my problem. In my case though the plugs were evenly tan. Does the fuel map for the rear cylinder look fine?
Could very well be a bad intake seal. Easy to rule out. |
Kalali
| | Posted on Wednesday, September 16, 2009 - 11:12 am: |
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I just reread your post and I would say the injector o-rings might have been not correctly installed. Specially since the problem occurred right after you replaced them. Most definitely, I would say. |
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O2 sensor always lean