Technical question on O2 sensors
#11
10-05-2011 | 03:37 AM
Banned
Joined: Aug 2011
Posts: 122
Likes: 0
From: at home
K. The Harley tech here told it to me like this. If you put a high flow airE cleaner and pipes on a fuel injected Harley the ecu recognizes there is more air going in and out so it adjusts and adds more fuel HOWEVER it is still trying to maintain a 14.7-1 a/f ratio which as we all know is good for emissions but not power. He suggested unless I was going to get into the motor(cams,headwork,etc) a simple enricher(fuel pak) is all that's needed to get the a/f ratio into the 12s where max power is found. Or you can buy a 12 cent resistor from radio shack,install it inline from the o2 sensor and fool the ecu into believing that it's maintaining it's 14.7-1 a/f when in reality it's in the mid 12s. It made sense to me therefore I will accept his explaination as fact. Think about it b
Exactly! Best answer right here. Except I would put it into the 13 range instead of the 12. Xied's do that just fine and you don't have to spend a thousand dollars.
#12
10-05-2011 | 03:50 AM
Road Master
Joined: Jun 2010
Posts: 1,221
Likes: 4
From: Annemasse (border of Geneva-Switzerland) facing Mt-Blanc.
Correct me if I'm wrong but I think there is a simple answer to questions concerning O2 sensors:
- When the mixture gets too lean, do we get an error code ?
In principle YES:
- P0131 Front Oxygen Sensor Low
- P0151 Rear Oxygen Sensor Low
So a higher flow of air should be provided with more fuel to burn, otherwise this lean condition triggers one of these two diagnostic codes.
Different AFRs can be obtained by providing the ECU with a different interpretation of the read Lambda value using resistors as a fixed 'offset' throughout the range or via a programmable piggy-back mapping device to modulate this offset upon your needs. I will opt for the resistors
- When the mixture gets too lean, do we get an error code ?
In principle YES:
- P0131 Front Oxygen Sensor Low
- P0151 Rear Oxygen Sensor Low
So a higher flow of air should be provided with more fuel to burn, otherwise this lean condition triggers one of these two diagnostic codes.
Different AFRs can be obtained by providing the ECU with a different interpretation of the read Lambda value using resistors as a fixed 'offset' throughout the range or via a programmable piggy-back mapping device to modulate this offset upon your needs. I will opt for the resistors
#13
10-05-2011 | 06:09 AM
Tourer
Joined: Apr 2011
Posts: 472
Likes: 1
From: Hutchinson, Ks.
Dosent take a f&%$#@! rocket scientist to find signs of how youre engine is running. Just a general understanding of how it works. Like I said, idiots just listen towhat the masses say without making their own analysis.
Gas exhaust analysis at the stealer? You have a set of them built in to you're bike, they are oxygen sensors. If they cannot make you're afr 14.7 to one the little yellow light in you're dash will come on. A couple very bright harley techs even backed this up for me (off the clock of course when they werent trying to sell a million dollars worth of accessories).
And remember, anyone in the world can get on here and type ****. Use your own head man.
Gas exhaust analysis at the stealer? You have a set of them built in to you're bike, they are oxygen sensors. If they cannot make you're afr 14.7 to one the little yellow light in you're dash will come on. A couple very bright harley techs even backed this up for me (off the clock of course when they werent trying to sell a million dollars worth of accessories).
And remember, anyone in the world can get on here and type ****. Use your own head man.
#14
10-05-2011 | 08:46 AM
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Gas exhaust analysis at the stealer? You have a set of them built in to you're bike, they are oxygen sensors. If they cannot make you're afr 14.7 to one the little yellow light in you're dash will come on. A couple very bright harley techs even backed this up for me (off the clock of course when they werent trying to sell a million dollars worth of accessories).
And remember, anyone in the world can get on here and type ****. Use your own head man.
And remember, anyone in the world can get on here and type ****. Use your own head man.
#15
10-05-2011 | 09:01 AM
Seasoned HDF Member
Joined: Sep 2009
Posts: 16,667
Likes: 5,633
From: SE Michigan
Well, you know better than HD engineers? They say the ECM will compensate for Pipes and AC. Now, you may not like 14.7, but thats a different issue. The ECM will compensate for both a/c and pipes.
#16
10-05-2011 | 09:29 AM
Road Warrior
Joined: Jun 2009
Posts: 1,943
Likes: 3
From: NYC
agree....but the optimal is 13.5:1 AFR and the passive approach used in the XIED/VIED's will get you to about 14.2:1 AFR. Which is good enough for a stage I upgrade with SE slipon's. Don't know if it is good enough for a stage II upgrade or a stage III upgrade. AND, the XIED/VIED's only work while the bike is in close loop mode which is low to mid RPMS. If your cranking a lot of high RPMs the XIED/VIED's would not be the way to go. Another option are the wide band 02 sensors, which is probally the route I will take if the XIED's won't be enough for STAGE II or STAGE III.
#17
10-05-2011 | 09:29 AM
Road Captain
Joined: Jan 2009
Posts: 739
Likes: 2
From: St. Louis
From Fuel Motos website:
Q) Why does my Fuel Injected Harley Davidson need to be tuned?
A) All EFI Harley models are required to meet very lean EPA emissions standards with the stock components. The entire closed loop area has an AFR target of 14.6:1 which is very lean. In most calibrations closed loop is from idle up to approx 60% throttle or 80 kPa which during this time the ECM uses feedback from various sensors including the stock narrowband O2 sensors. The NB O2 sensors can only measure a small area near stoich which is 14.6:1 (+/- about .3) Besides the EFI systems ability to adjust for conditions such as ambient temperature, barometric pressure, etc... the EFI is designed to adjust for small variations such as inconsistencies in fuels and production tolerances based on the stock components but the primary function is to keep the AFR at 14.6:1. Although there is a window of adjustment It is simply not in its strategy or is it capable of adjusting for free flowing components such as an air cleaner or exhaust system. When you change these parts you can easily put the fuel requirements well outside of the EFI's window of adjustment as it is calibrated for the stock components. This is a problem, especially considering the closed loop AFR target in the stock calibration is 14.6:1 thru out the cruise range which is very lean. So what happens? You guessed it, if your fuel requirements are beyond the ECM's adjustment the mixture goes dangerously lean, well above 15:1. This is where you will feel poor throttle response, surging, detonation and in extreme cases engine damage. The higher RPM regions are generally not as much of a problem as the stock AFR targets have to be richer to prevent detonation, but they are certainly not optimum. For these reasons EFI tuning is one of the best improvements you can make to your bike.
Q) Why does my Fuel Injected Harley Davidson need to be tuned?
A) All EFI Harley models are required to meet very lean EPA emissions standards with the stock components. The entire closed loop area has an AFR target of 14.6:1 which is very lean. In most calibrations closed loop is from idle up to approx 60% throttle or 80 kPa which during this time the ECM uses feedback from various sensors including the stock narrowband O2 sensors. The NB O2 sensors can only measure a small area near stoich which is 14.6:1 (+/- about .3) Besides the EFI systems ability to adjust for conditions such as ambient temperature, barometric pressure, etc... the EFI is designed to adjust for small variations such as inconsistencies in fuels and production tolerances based on the stock components but the primary function is to keep the AFR at 14.6:1. Although there is a window of adjustment It is simply not in its strategy or is it capable of adjusting for free flowing components such as an air cleaner or exhaust system. When you change these parts you can easily put the fuel requirements well outside of the EFI's window of adjustment as it is calibrated for the stock components. This is a problem, especially considering the closed loop AFR target in the stock calibration is 14.6:1 thru out the cruise range which is very lean. So what happens? You guessed it, if your fuel requirements are beyond the ECM's adjustment the mixture goes dangerously lean, well above 15:1. This is where you will feel poor throttle response, surging, detonation and in extreme cases engine damage. The higher RPM regions are generally not as much of a problem as the stock AFR targets have to be richer to prevent detonation, but they are certainly not optimum. For these reasons EFI tuning is one of the best improvements you can make to your bike.
#18
10-05-2011 | 09:33 AM
Outstanding HDF Member
Joined: Apr 2008
Posts: 3,140
Likes: 15
From: Wisconsin
Always lively threads on this subject and always three schools, OEM ECU, XIED and tuners. Then you have all the different tuner schools ...... In the end, do what you think is right for you, but my advice, and it is just advice, study up a bit more than what guys post here, this is mostly subjective here. I was always a carb guy until four years ago, and I feel I have only touched the tip of the iceberg with my fuel injection ECM knowledge, so I listen here and I search other places. Working for an engine manufacturer also helps, I have a lot of resources to query. After all my learning, on my last bike I changed pipes and air cleaner, also went with a Fuel Pak, economical and got the job done for what I wanted. I know some more now and on the new bike I changed pipes, air and cam, so now I have gone with the PowerVision. Yes, I cold have done many other tuners, but I have been working with Fuel Moto and have built a trust that I feel confident with, so I went with their recommendation. Now, I am very happy with my motorcycle and the way it runs, regardless of whatever anyone says about my setup, so I am at peace. One thing, before I go, when people say their bike runs fine, or it runs great, that is their opinion. I used to think that way when I had my first FI bike, I thought I had it set up so sweet, until I rode the same bike my friend had, same setup, just tuned properly. Now I understand that runs strong, runs well, screams like a raped ape is all in the minds of the rider. We all want to think our bikes run great, but when they do, oh what joy. Peace!
#19
10-05-2011 | 09:53 AM
Road Warrior
Joined: Jun 2009
Posts: 1,943
Likes: 3
From: NYC
Or you can buy a 12 cent resistor from radio shack,install it inline from the o2 sensor and fool the ecu into believing that it's maintaining it's 14.7-1 a/f when in reality it's in the mid 12s.
#20
10-05-2011 | 09:55 AM
Seasoned HDF Member
Joined: Sep 2009
Posts: 16,667
Likes: 5,633
From: SE Michigan
well, they are in direct conflict with MoCo engineers on this then.
From Fuel Motos website:
Q) Why does my Fuel Injected Harley Davidson need to be tuned?
A) All EFI Harley models are required to meet very lean EPA emissions standards with the stock components. The entire closed loop area has an AFR target of 14.6:1 which is very lean. In most calibrations closed loop is from idle up to approx 60% throttle or 80 kPa which during this time the ECM uses feedback from various sensors including the stock narrowband O2 sensors. The NB O2 sensors can only measure a small area near stoich which is 14.6:1 (+/- about .3) Besides the EFI systems ability to adjust for conditions such as ambient temperature, barometric pressure, etc... the EFI is designed to adjust for small variations such as inconsistencies in fuels and production tolerances based on the stock components but the primary function is to keep the AFR at 14.6:1. Although there is a window of adjustment It is simply not in its strategy or is it capable of adjusting for free flowing components such as an air cleaner or exhaust system. When you change these parts you can easily put the fuel requirements well outside of the EFI's window of adjustment as it is calibrated for the stock components. This is a problem, especially considering the closed loop AFR target in the stock calibration is 14.6:1 thru out the cruise range which is very lean. So what happens? You guessed it, if your fuel requirements are beyond the ECM's adjustment the mixture goes dangerously lean, well above 15:1. This is where you will feel poor throttle response, surging, detonation and in extreme cases engine damage. The higher RPM regions are generally not as much of a problem as the stock AFR targets have to be richer to prevent detonation, but they are certainly not optimum. For these reasons EFI tuning is one of the best improvements you can make to your bike.
Q) Why does my Fuel Injected Harley Davidson need to be tuned?
A) All EFI Harley models are required to meet very lean EPA emissions standards with the stock components. The entire closed loop area has an AFR target of 14.6:1 which is very lean. In most calibrations closed loop is from idle up to approx 60% throttle or 80 kPa which during this time the ECM uses feedback from various sensors including the stock narrowband O2 sensors. The NB O2 sensors can only measure a small area near stoich which is 14.6:1 (+/- about .3) Besides the EFI systems ability to adjust for conditions such as ambient temperature, barometric pressure, etc... the EFI is designed to adjust for small variations such as inconsistencies in fuels and production tolerances based on the stock components but the primary function is to keep the AFR at 14.6:1. Although there is a window of adjustment It is simply not in its strategy or is it capable of adjusting for free flowing components such as an air cleaner or exhaust system. When you change these parts you can easily put the fuel requirements well outside of the EFI's window of adjustment as it is calibrated for the stock components. This is a problem, especially considering the closed loop AFR target in the stock calibration is 14.6:1 thru out the cruise range which is very lean. So what happens? You guessed it, if your fuel requirements are beyond the ECM's adjustment the mixture goes dangerously lean, well above 15:1. This is where you will feel poor throttle response, surging, detonation and in extreme cases engine damage. The higher RPM regions are generally not as much of a problem as the stock AFR targets have to be richer to prevent detonation, but they are certainly not optimum. For these reasons EFI tuning is one of the best improvements you can make to your bike.