Fuel management systems.
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1st Gear
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From: WV
Fuel management systems.
I put a set of VH Staggered Big Shots and a K and N high flow air filter on my 2009 FLSTCI. Runs great, no muddy accel, no backfires, etc. I noticed it's running hotter and I'm getting a little decel popping. Researched fixes. Likely the factory 14.7 AFR is too lean causing both problems. ViED and XiED will only correct to 14.0 at best ( might help the heat issue, might not). I'm considering FP3 (FP4 not compatible with 2009) but after reviewing the AFR charts (which dip into AFR 12-ish range). I'm wondering how can FP3 work with OEM narrow band O2 sensors which only srnse from 14 to 15. Is FP3 a scam? They say you don't have to have wideband sensors for FP3 but how can it work if the NB sensor only senses 14-15? Interested in your opinion, experience and some advice.
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When the AFR is set above or below the closed loop threshold the o2 sensors are ignored. In open loop the volumetric efficiency tables are used to determine how much fuel is needed for the target AFR. When you flash the bike with the tune from the FP3 it will modify the VE tables to add more fuel in the open loop range. It's not a scam. You can also add some fuel to the decel area to get rid of the popping. I like the power vision better because I can modify a tune on my computer, copy, paste, save backups.... Having to do everything with the phone app for the FP3 wasn't for me.
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1st Gear
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From: WV
Thanks, great info. So FP3 doesn't need wideband O2 sensors but having them can expand its functions? I noticed a post that discussed FP3 software updates using wideband sensors. Are there any reasonably priced ones for a 2009 FLSTCI?
Last edited by Garbonzo; May 20, 2023 at 11:27 PM.
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As Rusty Springs mentioned, only part of the OEM Harley tunes are Closed Loop (using O2 Sensor feedback) and a portion is Open Loop (no O2 sensor feedback and based off algorithms on OEM components) due to the small accuracy range of the narrowband O2 sensors. I can't remember off the top of my head, but a called for AFR around 14.3/14.2AFR is where the tune leaves closed loop and becomes open loop.
Any time a bike is tuned on a dyno, or when a new tune map is developed, they obviously use wide band O2 sensors to accurately cover all the cells on a tune map.
In my experience, you can get a good tune for an EFI bike with narrow band O2 sensors. For most riders on street driven bikes, except for extreme conditions or very aggressive riding, the vast majority of their time is spent in the portions of the tune MAP that are closed loop and covered by the narrow band O2 sensors.
The current trend in tuners is to have a module (or software) that will switch to Wide Band O2 sensors, and convert the OEM tune to an all closed loop tune. The PowerVision version is called Target Tune. While this will give O2 sensor feed back to the entire tune, and it is a good thing, IMHO it is not necessary.
The pre-O2 sensor bikes that had EFI, with all Open Loop tune maps, can run really well too. I have an '03 EFI Heritage with a big bore kit and headwork. It is pre-O2 sensor with an all open loop tune. It runs great.
Just as a side note, I have run Vance & Hines staggered Big Shots on two bikes. One with a carb and one with EFI... Pehaps I just got lazy with the tuning, but both bikes had a slight decel pop that I never did get rid of. It was minor, doesn't hurt anything, so I just chalked it up to the nature of the pipes...
Last edited by hattitude; May 21, 2023 at 08:54 AM.
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Until you get a device to see all of the data tables used to control the fuel it might be easy to assume anything of any remapping device.
The FP3 and Power Vision devices give you access to a whole range of canned maps for various exhaust setups and a higher flowing air filter.
My limited reading about O2 sensors is the wideband give an amount of how rich or lean the mixture is such that a computer could make the correction in one step. The narrow band sensors only indicate that the mixture is rich or lean and so the ECM will have to run some kind of algorithm to zero in on the correct mixture.
The FP3 and Power Vision devices give you access to a whole range of canned maps for various exhaust setups and a higher flowing air filter.
My limited reading about O2 sensors is the wideband give an amount of how rich or lean the mixture is such that a computer could make the correction in one step. The narrow band sensors only indicate that the mixture is rich or lean and so the ECM will have to run some kind of algorithm to zero in on the correct mixture.
Last edited by Andy from Sandy; May 21, 2023 at 09:01 AM.
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The ECM directly doesn't know how to use the wideband sensors. There is a tuner add-on for the power vision that does though.
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From: WV
Did some more research. Sounds like the power vision 4 is the way to go and narrow band O2 sensors will be just fine.. Not sure if it's auto tune capable yet though. They say it will be. Also, my 2009 FLSTCI receptacle under the seat only has 3 prongs. I emailed Fuel Moto about fitment. We'll see. Thanks for all your responses.
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Until you get a device to see all of the data tables used to control the fuel it might be easy to assume anything of any remapping device.
The FP3 and Power Vision devices give you access to a whole range of canned maps for various exhaust setups and a higher flowing air filter.
My limited reading about O2 sensors is the wideband give an amount of how rich or lean the mixture is such that a computer could make the correction in one step. The narrow band sensors only indicate that the mixture is rich or lean and so the ECM will have to run some kind of algorithm to zero in on the correct mixture.
The FP3 and Power Vision devices give you access to a whole range of canned maps for various exhaust setups and a higher flowing air filter.
My limited reading about O2 sensors is the wideband give an amount of how rich or lean the mixture is such that a computer could make the correction in one step. The narrow band sensors only indicate that the mixture is rich or lean and so the ECM will have to run some kind of algorithm to zero in on the correct mixture.
I'm not an expert, but I believe the algorithms are written into the tune and not modified in any way, UNLESS the tune is in closed loop.
Wide band sensors sample AFRs from 10.0:1 to 18.0:1
Narrow band sensors sample AFRs from 14.3:1 to 15.2:1
For gasoline fuel, the stoichiometric airfuel mixture is about 14.7:1.
So if you look at the AFR table of any OEM Harley EFI fuel map, if the called for AFR is greater than 14.3:1 up to Stoich (14.7:1), then that portion of the MAP is in Closed Loop (w/O2 sensor feedback). If the called for AFR is 14.3 or lower, then that portion of the MAP is in Open Loop (no O2 sensor feedback) and is based on tune algorithms from sensor readings (temp, MAF, MAP, and/or throttle position) within the parameters of the mod package (air cleaner, exhaust, cams, etc) the map was set up for.
In other words, the O2 sensors don't get involved in any AFR at or below 14.3.....
Oversimplified, modules like Target tune modify the signals of the wide band sensors to the ECM, then the ECM signals to the injectors, so the entire tune is accurately measured, and instantaneously adjusted, in closed loop.
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I am not very tech savvy when it comes to this stuff. But I thought throwing in this link might help you. But the one thing that I can assure you is, once you have all your gear in place, get her Dyno Tuned., the difference will be night and day. Sounds to me like you should throw in some cams. lol Don't mind, I just love to spend other people's money. 
Harley Davidson FLSTC Heritage Softail Classic 2009 | Dynojet
Harley Davidson FLSTC Heritage Softail Classic 2009 | Dynojet
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