Help needed with engine tune
Thread Starter
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2nd Gear
Joined: Aug 2012
Posts: 6
Likes: 0
From: Woodinville
Help needed with engine tune
Hello, thanks for taking a look at this!
I own a 2008 Road King with Stage II, as follows.
When the bike is warmer the problem reduces but the bike now hesitates and stutters around 2,500 rpm when held constant with little load (not lugging). The bike still accelerates and pulls well when you give it gas.
Occasionally a "Front O2 Sensor Low" diagnostic trouble code gets thrown and the plugs are very white in color.
The bike had a professional dyno tune about 2 years ago. It dynoed at 107 ft lbs torque and has run very well for the past two years. This new condition is sudden onset without any changes or modifications being made to the bike.
On face value it seems like a lean running condition but I can't find any explanation as to why it would suddenly start running lean.
I have tried re-flashing the ECM with the dyno fuel map and just for kicks tried a stock HD fuel map that is closest to my configuration but that made absolutely no difference.
I have also looked for obvious problems like air leaks at the intake or exhaust manifold, but to my naked (and inexperienced) eye I see nothing that looks wrong.
The Harley dealer simply wants to dyno tune the bike again (at $450) to fix it, which I do not agree with. I'm sure they can reduce the symptoms by tuning them out but there is an underlying fault I want to find first.
I'm hoping someone can help me track the problem down.
I do have a 3 minute data dump from the ECM downloaded using the Screamin Eagle Super Tuner software that captures all the values from the engine whilst it is acting up. I don't understand the numbers well enough to know what they mean, however.
Can anyone help?
Thanks in advance.
I own a 2008 Road King with Stage II, as follows.
- 103 CI Big Bore
- Flat Top Pistons
- 255 CAMS
- SE Heavy Breather
- VH True Duals
- Rinehart Mufflers
When the bike is warmer the problem reduces but the bike now hesitates and stutters around 2,500 rpm when held constant with little load (not lugging). The bike still accelerates and pulls well when you give it gas.
Occasionally a "Front O2 Sensor Low" diagnostic trouble code gets thrown and the plugs are very white in color.
The bike had a professional dyno tune about 2 years ago. It dynoed at 107 ft lbs torque and has run very well for the past two years. This new condition is sudden onset without any changes or modifications being made to the bike.
On face value it seems like a lean running condition but I can't find any explanation as to why it would suddenly start running lean.
I have tried re-flashing the ECM with the dyno fuel map and just for kicks tried a stock HD fuel map that is closest to my configuration but that made absolutely no difference.
I have also looked for obvious problems like air leaks at the intake or exhaust manifold, but to my naked (and inexperienced) eye I see nothing that looks wrong.
The Harley dealer simply wants to dyno tune the bike again (at $450) to fix it, which I do not agree with. I'm sure they can reduce the symptoms by tuning them out but there is an underlying fault I want to find first.
I'm hoping someone can help me track the problem down.
I do have a 3 minute data dump from the ECM downloaded using the Screamin Eagle Super Tuner software that captures all the values from the engine whilst it is acting up. I don't understand the numbers well enough to know what they mean, however.
Can anyone help?
Thanks in advance.
Cruiser
Joined: Mar 2012
Posts: 210
Likes: 0
From: San Antonio
Sounds to me like you have a Bad O/2 sensor acting up..i would replace that frt O/2 and reset the fuel trims and see what it does.. do you still have the tune you have been using for all this time and can reflash it with that tune??
Road Captain
Joined: Feb 2006
Posts: 521
Likes: 3
From: Virginia
Hello, thanks for taking a look at this!
I own a 2008 Road King with Stage II, as follows.
When the bike is warmer the problem reduces but the bike now hesitates and stutters around 2,500 rpm when held constant with little load (not lugging). The bike still accelerates and pulls well when you give it gas.
Occasionally a "Front O2 Sensor Low" diagnostic trouble code gets thrown and the plugs are very white in color.
The bike had a professional dyno tune about 2 years ago. It dynoed at 107 ft lbs torque and has run very well for the past two years. This new condition is sudden onset without any changes or modifications being made to the bike.
On face value it seems like a lean running condition but I can't find any explanation as to why it would suddenly start running lean.
I have tried re-flashing the ECM with the dyno fuel map and just for kicks tried a stock HD fuel map that is closest to my configuration but that made absolutely no difference.
I have also looked for obvious problems like air leaks at the intake or exhaust manifold, but to my naked (and inexperienced) eye I see nothing that looks wrong.
The Harley dealer simply wants to dyno tune the bike again (at $450) to fix it, which I do not agree with. I'm sure they can reduce the symptoms by tuning them out but there is an underlying fault I want to find first.
I'm hoping someone can help me track the problem down.
I do have a 3 minute data dump from the ECM downloaded using the Screamin Eagle Super Tuner software that captures all the values from the engine whilst it is acting up. I don't understand the numbers well enough to know what they mean, however.
Can anyone help?
Thanks in advance.
I own a 2008 Road King with Stage II, as follows.
- 103 CI Big Bore
- Flat Top Pistons
- 255 CAMS
- SE Heavy Breather
- VH True Duals
- Rinehart Mufflers
When the bike is warmer the problem reduces but the bike now hesitates and stutters around 2,500 rpm when held constant with little load (not lugging). The bike still accelerates and pulls well when you give it gas.
Occasionally a "Front O2 Sensor Low" diagnostic trouble code gets thrown and the plugs are very white in color.
The bike had a professional dyno tune about 2 years ago. It dynoed at 107 ft lbs torque and has run very well for the past two years. This new condition is sudden onset without any changes or modifications being made to the bike.
On face value it seems like a lean running condition but I can't find any explanation as to why it would suddenly start running lean.
I have tried re-flashing the ECM with the dyno fuel map and just for kicks tried a stock HD fuel map that is closest to my configuration but that made absolutely no difference.
I have also looked for obvious problems like air leaks at the intake or exhaust manifold, but to my naked (and inexperienced) eye I see nothing that looks wrong.
The Harley dealer simply wants to dyno tune the bike again (at $450) to fix it, which I do not agree with. I'm sure they can reduce the symptoms by tuning them out but there is an underlying fault I want to find first.
I'm hoping someone can help me track the problem down.
I do have a 3 minute data dump from the ECM downloaded using the Screamin Eagle Super Tuner software that captures all the values from the engine whilst it is acting up. I don't understand the numbers well enough to know what they mean, however.
Can anyone help?
Thanks in advance.
Thread Starter
|
2nd Gear
Joined: Aug 2012
Posts: 6
Likes: 0
From: Woodinville
Hey Txlen, thanks for responding - what does "reset the fuel trims" mean? Are you saying that changing out the O2 sensors requires some sort of recalibration?
Cruiser
Joined: Mar 2012
Posts: 210
Likes: 0
From: San Antonio
What are you tuning it with??.. some of the tuning programs such as the Power Vision have and option to reset all the fuel trims and adaptives to start relearning fresh all over again... you could prob even try unhooking the battery and touch the cables together for about 20 secs or so ..
Thread Starter
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2nd Gear
Joined: Aug 2012
Posts: 6
Likes: 0
From: Woodinville
I think you were on the right track checking for intake leaks. Don't know about your bike but mine has a rubber cap on an unused port coming off the intake manifold. This could be dry rotted allowing air in leakage. I'd continue on this path with some carb cleaner or starting fluid spraying the intake manifold area. If you hear a change in the engine you will have found a leak. I've also heard that using propane works very well and finds even the smallest leak although I've never tried it myself. Lastly, I wouldn't be screwing around with the tune. I personally feel the dealer you consulted is looking to get deep in your wallet if they immediately suggested a dyno tune especially after your description of the problem. Good luck.
Don't get me wrong, a good dyno tune is worth the money, but the problem is that very few know how to do it well IMO.
I also think that tuning shouldn't be used as a way to mask another problem. There are so many things you can adjust in the ECM that I have no doubt they could mask the symptoms I'm seeing, for example, by setting the AF super rich to compensate. But masking the symptom is not the same as fixing the problem!
I will try your starter fluid idea - thanks!
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Thread Starter
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2nd Gear
Joined: Aug 2012
Posts: 6
Likes: 0
From: Woodinville
What are you tuning it with??.. some of the tuning programs such as the Power Vision have and option to reset all the fuel trims and adaptives to start relearning fresh all over again... you could prob even try unhooking the battery and touch the cables together for about 20 secs or so ..
What I can do after swapping out the sensors is reflash the ECM with the original config. file - I'm guessing that the equivalent of resetting the ECM calibration.
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Cruiser
Joined: Mar 2012
Posts: 210
Likes: 0
From: San Antonio
I'm using the Screamin Eagle Super Tuner. Its an interface box that plugs in temporarily between a PC and the ECM. You can upload a fuel map and configuration file generated using the software provided, from the PC to the ECM via the interface. Unfortunately this product has no "learning" or auto-calibration functionality.
What I can do after swapping out the sensors is reflash the ECM with the original config. file - I'm guessing that the equivalent of resetting the ECM calibration.
What I can do after swapping out the sensors is reflash the ECM with the original config. file - I'm guessing that the equivalent of resetting the ECM calibration.
