| Author |
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Akbuell
| | Posted on Friday, September 18, 2020 - 12:43 pm: | 
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O.K. The bike runs great with an AFV of 100. The injectors passed the leak test.
Something is causing the ECM to read a rich mixture and leaning out the entire fuel map. Possible a faulty O2 sensor reading? Something to try, if you enjoy fiddling with stuff, is to swap front and rear injectors and see if the AFV changes much. My thinking is if the injector is partially clogged, that may cause a rich mixture.
Counterintuitive, I know, but it is my understanding that a clogged injector will spray more of a stream of fuel than a mist. The stream droplets have a smaller overall surface area than a mist, leading to incomplete combustion, and a 'rich' mixture.
Hope this helps, Dave |
Tpehak
| | Posted on Friday, September 18, 2020 - 01:21 pm: |
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You can't swap rear and front injectors, they are different, they have directional nozzle, front should go to front hole and rear should go to rear hole, if you stick them opposite way they will spray fuel on the intake walls instead of to the intake valves.
(Message edited by TPEHAK on September 18, 2020) |
Akbuell
| | Posted on Friday, September 18, 2020 - 01:58 pm: |
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Tpehak:
Thanks for that. I'm more used to the tubers, where they are both the same.
Mea Culpa, Dave :-) |
Baybueller
| | Posted on Friday, September 18, 2020 - 02:33 pm: |
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I am thinking O2 sensor. Bike runs great at 100% and poorly with backfire as the AVF value goes down.
I have done the sensors/ injector change on another 08 I had. Not fun.
When I get the replacement VR I am going to set the AFV min. at 95 and see how it goes.
I love these bikes but now remember when I sold the last about 6 years ago it was partly due to dwindling parts access. Al Lighton was just closing shop. |
Baybueller
| | Posted on Tuesday, September 22, 2020 - 04:01 pm: |
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Getting there.
Installed used VR from ebay, working ok. I noticed the backing on the old one had cracks and a tear, guessing moisture got in.
New ecm with jardine map installed, IDM says it's close. Bike runs rough cold then very well. The AFV stays at 100% and now the only problem is very low idle when hot to the point it dies.
I don't see throttle voltage on the ecmdroid so i'm guessing tps problem.
Looks like the big problems are done now its the small stuff. |
Tpehak
| | Posted on Tuesday, September 22, 2020 - 04:09 pm: |
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ECM Droid shows TPS angle, not voltage. Voltage does not matter after TPS reset, what matter is the TPS angle should change linearly from lower to upper value without jumping and lower and upper values should not change over time and are withing limits according service manual.
(Message edited by TPEHAK on September 22, 2020) |
Skipbarberman
| | Posted on Wednesday, September 23, 2020 - 07:29 am: |
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ECM Droid show TPS angle as an interpretation of voltage. The concept of 'jumps'or non-linear change would imply additional resistance, or, continuity problems and a voltage spike - a bad sensor - resulting in fueling issues.
TPS Voltage is the 5V reference signal to ensure the sensor is seeing the proper input voltage. The output voltage is then compared to preset values that indicate throttle angle.
Glad to hear your back up and running, they are a blast when running well.
(Message edited by skipbarberman on September 23, 2020)
(Message edited by skipbarberman on September 23, 2020) |
Baybueller
| | Posted on Wednesday, September 23, 2020 - 08:01 pm: |
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The tps rolls smooth from 4 to 85 degrees.
I ran a load of injector cleaner thru the motor when I got the bike and think that may have effected the o2 sensor.
Good news is I can ride it now while I sort it out.
Thanks again for your thoughts and idea's. |
Starbellied_sneetch
| | Posted on Thursday, September 24, 2020 - 04:05 pm: |
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Since you already have Buelltooth, you can very easily just bypass the 02 sensor by disabling closed loop operation. The instructions on how to do so are easy to find. If the 02 sensor is at fault, it won't matter, because the bike won't be using it anymore. I think you'll have to reset the TPS after doing so. |
Baybueller
| | Posted on Thursday, September 24, 2020 - 10:47 pm: |
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Since the idle drops to engine stall when warm I tried to read up on the idle air controller in the shop manual.
Two pages on the air cleaner but not a word I could find on the iac.
The one thing I know is the little bastard is expensive. |
Tpehak
| | Posted on Friday, September 25, 2020 - 09:17 am: |
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Shop manual does not have such information. For ECM, IAC and another engine related issues you need electrical manual. |
Baybueller
| | Posted on Friday, September 25, 2020 - 10:20 pm: |
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Ok, looking at the right book I did the listen test. Seems to work as described.
Runs good but at 25 mpg I think its a little rich.
The adventure continues. |
Akbuell
| | Posted on Saturday, September 26, 2020 - 12:15 pm: |
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One possible thing to try:
Since it passed the listen test, might check the air inlet controlled by the IAC, and the IAC itself for carbon, ect it might have accumulated due to poor running and backfiring through the intake manifold. Would be nice to find that it is just dirty.
It has been a while since I checked, but I seem to remember my XB-TT does not get the mileage my tubers do. That said, 25 mpg does seem low.
Hope this helps, Dave |
Baybueller
| | Posted on Saturday, September 26, 2020 - 03:58 pm: |
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Thanks. I'm trying to dance around getting in deep. If I do its full injector, tps, temp and o2 sensor.
Probably just putting off the inevitable. |
Shoggin
| | Posted on Saturday, September 26, 2020 - 09:41 pm: |
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You sure want to keep spending a ton of money on it. Hope you get lucky with that path.
All of those parts are simple to check if they are actually bad or not. You're in luck though! Buells don't have that many sensors so you'll get lucky eventually. LOL
Unless it's something else entirely thats causing your problem. |
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