Do EFI engines have O2 sensors?
Thread Starter
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Banned
Joined: Oct 2009
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From: FL
Do EFI engines have O2 sensors?
O2 sensors were used I think on all domestic fuel injected cars beginning from 83-85. Some antique cars such as 76 Jaguars didn't have O2 sensors which means computers didn't adjust fuel according to exhaust. Probably from 95-98 car computers were self learning, they reprogrammed themselves according to changing conditions such as dirty air filter for example.
The reason I am writing it is if HD have O2 sensors and self learning computers there is no need for aftermarket computers.
When HD got O2 sensors if they did? Do they have self learning computers?
The reason I am writing it is if HD have O2 sensors and self learning computers there is no need for aftermarket computers.
When HD got O2 sensors if they did? Do they have self learning computers?
Outstanding HDF Member
Joined: Apr 2006
Posts: 2,537
Likes: 21
It is somewhat of a learning program, it's called Adaptive Fuel..... Came from Buell...
In closed loop operation the ECM uses the oxygen sensor to tell if the fuel mixture is rich or lean. However, due to the characteristics of the oxygen sensor it can’t tell exactly how rich or lean, it only knows that the mixture is richer or leaner than optimum. The ECM will enrich the mixture if the oxygen sensor shows that the mixture is lean, and lean the mixture if it looks rich. The result of this is that the mixture will swing back and forward around the stoichiometric point or the set point of that particular O2 sensor.
Harley-Davidson Motor Company started using O2 sensors with the 2006 EFI Dyna models and today all Harley’s use O2 sensors and can operate in ‘Closed Loop’ mode. Harley uses what is called a narrow band or switching sensor which controls over a very narrow range that is near stoichiometric (14.6 AFR). In some circumstances the tuner may want to move this control point, and the ability to do this is accomplished with the Super Tuner by adjusting the Closed-Loop Bias table. This table will allow moving the O2 set point by about ą 0.5 AFR. Trying to skew the set point by more than ą 0.5
AFR causes the sensor to become inaccurate.
In closed loop operation the ECM uses the oxygen sensor to tell if the fuel mixture is rich or lean. However, due to the characteristics of the oxygen sensor it can’t tell exactly how rich or lean, it only knows that the mixture is richer or leaner than optimum. The ECM will enrich the mixture if the oxygen sensor shows that the mixture is lean, and lean the mixture if it looks rich. The result of this is that the mixture will swing back and forward around the stoichiometric point or the set point of that particular O2 sensor.
Harley-Davidson Motor Company started using O2 sensors with the 2006 EFI Dyna models and today all Harley’s use O2 sensors and can operate in ‘Closed Loop’ mode. Harley uses what is called a narrow band or switching sensor which controls over a very narrow range that is near stoichiometric (14.6 AFR). In some circumstances the tuner may want to move this control point, and the ability to do this is accomplished with the Super Tuner by adjusting the Closed-Loop Bias table. This table will allow moving the O2 set point by about ą 0.5 AFR. Trying to skew the set point by more than ą 0.5
AFR causes the sensor to become inaccurate.
Road Master
Joined: Dec 2006
Posts: 1,058
Likes: 6
From: Omaha Nebraska
Also, the adaptive learning does not occur at wide open throttle (WOT) due to WOT requiring a different air to fuel (A/F) ratio out of the measurement range of narrow band O2 sensors. However, the adaptive learning does apply a portion of what it learned at partial throttle to WOT which usually results in an incorrect, potentially damaging A/F ratio on a modified engine such as changing exhaust, cams, etc.
The solution to this problem is to reprogram the factory ECU with a SERT program or install a programmable piggyback to factory ECU or an aftermarket, programmable ECU. Some of these installs have a wide band rather then the narrow band O2 sensor that can monitor and adjust for the required A/F ratio at WOT on modified engines. This explanation also applies to and is common practice on modified car and truck engines.
Hope we have answered your question.
The solution to this problem is to reprogram the factory ECU with a SERT program or install a programmable piggyback to factory ECU or an aftermarket, programmable ECU. Some of these installs have a wide band rather then the narrow band O2 sensor that can monitor and adjust for the required A/F ratio at WOT on modified engines. This explanation also applies to and is common practice on modified car and truck engines.
Hope we have answered your question.
The reason to move to an aftermarket ECM is the level of control you can obtain over various aspects of the engine. The reason to use a tuner like TTS is to gain simular control but its limited by the availible adjustments in the OEM ECM.
The goal of the HD ECM is to provide as much power as possible while maintaining legal emmissions, with emmissions being paramount. And emmissions standards are not aligned with making the most power out of our air cooled, pushrod, engines.
Look further here, there is alot of discussion on different tuning devices and programs. Depending on your end goals, you may need none of them.
...gene
The goal of the HD ECM is to provide as much power as possible while maintaining legal emmissions, with emmissions being paramount. And emmissions standards are not aligned with making the most power out of our air cooled, pushrod, engines.
Look further here, there is alot of discussion on different tuning devices and programs. Depending on your end goals, you may need none of them.
...gene
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Banned
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From: FL
Thanks, guys. I understood that that the most power comes from not perfect 14.7 ratio, I guess it is richer mix. If it is so "power program" will probably slowly kill O2 unless it is replaced to 5V sensor.
Road Warrior
Joined: Apr 2009
Posts: 1,360
Likes: 4
Least emissions occur when the fuel is entirely burned, and it turns out that its where the most power is made as that's where the most BTU is extracted from the fuel. The A/F mix that burns 100% varies from fuel to fuel and pump to pump, so an ideal system would automatically adapt the fuel mix for the fuel you happen to have in the tank.
Everyone wants cheep transportation, sensors, computers, fuel injection is not cheap. Once upon the time, however, someone had a desire to reduce exhaust emissions, regardless of cost. In the real world the technology does not exist to achieve the ideal. As a result, the real world is full of compromise. Running ideal A/F mix may be OK cruising but at WOT is too hot for air cooled engines to handle, many water cooled motors also have problems. Its not only temperature, a engine running a little leaner than ideal will have significant drivability issue, were you can run a lot richer without impacting drivability significantly. So you would like, perhaps to run a little cooler (richer A/F) as a safety measure when accelerating but near ideal A/F while cruising. The other limitation is that there is no practical sensor available that can tell you the A/F mix let alone if the fuel is burning correctly. Its all guesswork, and with guesswork some guesses are better than others. The best you can do is measure A/F mix indirectly by using an O2 sensor, something that provides an indication of O2 in the exhaust. Here we run into another technology limit (O2 sensors have a lot of limitations). The most accurate and durable sensors detect a fairly narrow range. They do not cover both the desired cruising and WOT mix. So you install either two narrow band sensors or install one to cover 90% of the operating time, and guess at the 10%. You can also use a less accurate and less durable (in a vehicle application) and more expensive consumer quality wide band O2 sensor, few manufactures chose this approach. Lab quality, sometimes consumer quality WB sensors are used in dynos where the sensors can be routinely calibrated and accuracy checked and replaced often just to be sure accurate data is collected.
So in the cruising range the ECU can be pretty close to ideal A/F. Since the ECU is not measuring A/F directly, just guessing based on a O2 sensor, you will not be running ideal, but can be close. The ECU will be guessing otherwise, based on how much air is being pumped by the engine, so called VE, and a number of different sensors. The VE varies significantly from one motor to another and with different kinds of mods. So the better you can measure the VE the better the ECU's guesses will be. This is basically what a dyno tuner or TTS does. Determine the VE, and based on the tuners experience, tell the ECU to squirt this much fuel and light off the spark at this time for this set of a number of different sensor readings including or ignoring the O2 sensor (and guessing across the board).
In the real world street application, this narrow band sensor VE calculation and guesses appear to result in optimum performance/emissions. Be careful about drinking the wideband sensor's coolaid as in a vehicle they give less accurate readings (can't be trusted as much), so the ECU adds a safety factor. More safety factor, less power, less safety factor more risk of damage. Vehicles can be made to run well with either approach. Oh, you get a slightly different A/F from tank to tank even when the O2 sensor reading is the same. Its more noticeable in fuel variation from one area of the country/world to another. More safety factor (more fuel) is added across the board to compensate.
So there is theory but there is no way to implement the theory, no tools. There are a bunch of compromises that skins the cat, some better than others, and that's where the lively discussion is.
BTW, the Delphi ECU is a very good unit. Its not set up for wideband O2 sensors, however. If you want to use wideband O2s, you need to add hardware adapters or replace the ECU.
Everyone wants cheep transportation, sensors, computers, fuel injection is not cheap. Once upon the time, however, someone had a desire to reduce exhaust emissions, regardless of cost. In the real world the technology does not exist to achieve the ideal. As a result, the real world is full of compromise. Running ideal A/F mix may be OK cruising but at WOT is too hot for air cooled engines to handle, many water cooled motors also have problems. Its not only temperature, a engine running a little leaner than ideal will have significant drivability issue, were you can run a lot richer without impacting drivability significantly. So you would like, perhaps to run a little cooler (richer A/F) as a safety measure when accelerating but near ideal A/F while cruising. The other limitation is that there is no practical sensor available that can tell you the A/F mix let alone if the fuel is burning correctly. Its all guesswork, and with guesswork some guesses are better than others. The best you can do is measure A/F mix indirectly by using an O2 sensor, something that provides an indication of O2 in the exhaust. Here we run into another technology limit (O2 sensors have a lot of limitations). The most accurate and durable sensors detect a fairly narrow range. They do not cover both the desired cruising and WOT mix. So you install either two narrow band sensors or install one to cover 90% of the operating time, and guess at the 10%. You can also use a less accurate and less durable (in a vehicle application) and more expensive consumer quality wide band O2 sensor, few manufactures chose this approach. Lab quality, sometimes consumer quality WB sensors are used in dynos where the sensors can be routinely calibrated and accuracy checked and replaced often just to be sure accurate data is collected.
So in the cruising range the ECU can be pretty close to ideal A/F. Since the ECU is not measuring A/F directly, just guessing based on a O2 sensor, you will not be running ideal, but can be close. The ECU will be guessing otherwise, based on how much air is being pumped by the engine, so called VE, and a number of different sensors. The VE varies significantly from one motor to another and with different kinds of mods. So the better you can measure the VE the better the ECU's guesses will be. This is basically what a dyno tuner or TTS does. Determine the VE, and based on the tuners experience, tell the ECU to squirt this much fuel and light off the spark at this time for this set of a number of different sensor readings including or ignoring the O2 sensor (and guessing across the board).
In the real world street application, this narrow band sensor VE calculation and guesses appear to result in optimum performance/emissions. Be careful about drinking the wideband sensor's coolaid as in a vehicle they give less accurate readings (can't be trusted as much), so the ECU adds a safety factor. More safety factor, less power, less safety factor more risk of damage. Vehicles can be made to run well with either approach. Oh, you get a slightly different A/F from tank to tank even when the O2 sensor reading is the same. Its more noticeable in fuel variation from one area of the country/world to another. More safety factor (more fuel) is added across the board to compensate.
So there is theory but there is no way to implement the theory, no tools. There are a bunch of compromises that skins the cat, some better than others, and that's where the lively discussion is.
BTW, the Delphi ECU is a very good unit. Its not set up for wideband O2 sensors, however. If you want to use wideband O2s, you need to add hardware adapters or replace the ECU.
Last edited by ColdCase; Oct 23, 2009 at 09:26 AM.
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Stellar HDF Member
Joined: Sep 2007
Posts: 2,469
Likes: 679
From: Vancouver Island B.C.
Least emissions occur when the fuel is entirely burned, and it turns out that its where the most power is made as that's where the most BTU is extracted from the fuel. The A/F mix that burns 100% varies from fuel to fuel and pump to pump, so an ideal system would sense the correct fuel mix for the fuel you happen to have in the tank.
Everyone wants cheep transportation, sensors, computers, fuel injection is not cheap. Once upon the time, however, someone had a desire to reduce exhaust emissions, regardless of cost. In the real world the technology does not exist to achieve the ideal. As a result, the real world is full of compromise. Running ideal A/F mix may be OK cruising but at WOT is too hot for air cooled engines to handle, many water cooled motors also have a problems. So you would like, perhaps to run a little cooler (richer A/F) as a safety measure when accelerating but near ideal A/F while cruising. The other limitation is that there is no practical sensor available that can tell you the A/F mix let alone if the fuel is burning correctly. Its all guesswork, and with guesswork some guesses are better than others. The best you can do is measure A/F mix indirectly by using an O2 sensor, something that provides an indication of O2 in the exhaust. Here we run into another technology limit, the most accurate and durable sensors detect a fairly narrow range. They do not cover both the desired cruising and WOT mix. So you install either two narrow band sensors or install one to cover 90% of the operating time, and guess at the 10%. You can also use a less accurate and less durable (in a vehicle application) and more expensive wide band O2 sensor, few manufactures chose this approach. WB sensors are used in dynos where the sensors can be routinely calibrated and accuracy checked and replaced often just to be sure accurate data is collected.
So in the cruising range the ECU can be pretty close to ideal A/F. Since the ECU is not measuring A/F directly, just guessing based on a O2 sensor, you will not be running ideal, but can be close. The ECU will be guessing otherwise, based on how much air is being pumped by the engine, so called VE, and a number of different sensors. The VE varies significantly from one motor to another and with different kinds of mods. So the better you can measure the VE the better the ECU's guesses will be. This is basically what a dyno tuner or TTS does. Determine the VE, and based on the tuners experience, tell the ECU to squirt this much fuel and light off the spark at this time for this set of a number of different sensor readings.
In the real world street application, this narrow band sensor VE calculation and guesses appear to result in optimum performance/emissions. Be careful about drinking the wideband sensor's coolaid as in a vehicle they give less accurate readings (can't be trusted as much), so the ECU adds a safety factor. More safety factor, less power, less safety factor more risk of damage. Vehicles can be made to run well with either approach.
So there is theory but there is no way to implement the theory, no tools. There are a bunch of compromises that skins the cat, some better than others, and that's where the lively discussion is.
BTW, the Delphi ECU is a very good unit. Its not set up for wideband O2 sensors, however. If you want to use wideband O2s, you need to add hardware adapters or replace the ECU.
Everyone wants cheep transportation, sensors, computers, fuel injection is not cheap. Once upon the time, however, someone had a desire to reduce exhaust emissions, regardless of cost. In the real world the technology does not exist to achieve the ideal. As a result, the real world is full of compromise. Running ideal A/F mix may be OK cruising but at WOT is too hot for air cooled engines to handle, many water cooled motors also have a problems. So you would like, perhaps to run a little cooler (richer A/F) as a safety measure when accelerating but near ideal A/F while cruising. The other limitation is that there is no practical sensor available that can tell you the A/F mix let alone if the fuel is burning correctly. Its all guesswork, and with guesswork some guesses are better than others. The best you can do is measure A/F mix indirectly by using an O2 sensor, something that provides an indication of O2 in the exhaust. Here we run into another technology limit, the most accurate and durable sensors detect a fairly narrow range. They do not cover both the desired cruising and WOT mix. So you install either two narrow band sensors or install one to cover 90% of the operating time, and guess at the 10%. You can also use a less accurate and less durable (in a vehicle application) and more expensive wide band O2 sensor, few manufactures chose this approach. WB sensors are used in dynos where the sensors can be routinely calibrated and accuracy checked and replaced often just to be sure accurate data is collected.
So in the cruising range the ECU can be pretty close to ideal A/F. Since the ECU is not measuring A/F directly, just guessing based on a O2 sensor, you will not be running ideal, but can be close. The ECU will be guessing otherwise, based on how much air is being pumped by the engine, so called VE, and a number of different sensors. The VE varies significantly from one motor to another and with different kinds of mods. So the better you can measure the VE the better the ECU's guesses will be. This is basically what a dyno tuner or TTS does. Determine the VE, and based on the tuners experience, tell the ECU to squirt this much fuel and light off the spark at this time for this set of a number of different sensor readings.
In the real world street application, this narrow band sensor VE calculation and guesses appear to result in optimum performance/emissions. Be careful about drinking the wideband sensor's coolaid as in a vehicle they give less accurate readings (can't be trusted as much), so the ECU adds a safety factor. More safety factor, less power, less safety factor more risk of damage. Vehicles can be made to run well with either approach.
So there is theory but there is no way to implement the theory, no tools. There are a bunch of compromises that skins the cat, some better than others, and that's where the lively discussion is.
BTW, the Delphi ECU is a very good unit. Its not set up for wideband O2 sensors, however. If you want to use wideband O2s, you need to add hardware adapters or replace the ECU.
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Outstanding HDF Member
Joined: Sep 2005
Posts: 2,893
Likes: 2
From: USA
The reason to move to an aftermarket ECM is the level of control you can obtain over various aspects of the engine. The reason to use a tuner like TTS is to gain simular control but its limited by the availible adjustments in the OEM ECM.
The goal of the HD ECM is to provide as much power as possible while maintaining legal emmissions, with emmissions being paramount. And emmissions standards are not aligned with making the most power out of our air cooled, pushrod, engines.
Look further here, there is alot of discussion on different tuning devices and programs. Depending on your end goals, you may need none of them.
...gene
The goal of the HD ECM is to provide as much power as possible while maintaining legal emmissions, with emmissions being paramount. And emmissions standards are not aligned with making the most power out of our air cooled, pushrod, engines.
Look further here, there is alot of discussion on different tuning devices and programs. Depending on your end goals, you may need none of them.
...gene
Engine Cranking
Clearing Flooding Mode
IAC Crank Steps Constant
Engine Crank to Run Transition
Engine Idle and Warmup
Warmup Enrichment
Idle Spark
VE Tables both cylinders
AFR Tables open and closed loop
Closed loop bias table
Adaptive fuel control
Stoichiometric Air-Fuel ratio, Lambda, and o2 sensors
Power Enrichment (PE) mode
Transient Fuel
Acceleration Enrichment table
Deceleration Enleanment table
Main Spark tables
Spark Temperature Correction table
Adaptive Spark control
EITMS - Engine Idle Temperature Management system
What is missing that you would like to tune with TTS thats not on this list?