O2 sensor voltage output at optimum AFR?
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Anybody? How about you guys with the SMT6? My research and trials suggests an optimal tuning results in 0.88 volts coming out of the O2 sensor during closed loop acceleration.
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Optimally tuned during closed loop? This varries under operating conditions.
CONDITION
Part throttle cruzing under light load - The air/fuel mix should be optimal at 14.7 to 1. Your O2 signal will be 1.0 volts at 14.7 to 1.
Full throttle, heavy load - The A/F mix should be around 11.5/1. Your O2 signal will be around 0.8 volts.
Closed throttle, decelleration - The A/F mix will be around 21/1. The O2 signal will be around 1.5 volts.
The lower the O2 sensor voltage (.05) the richer the mixture. When you see low voltages, your O2 sensor is asking the engine management to lean out the mixture. Under full throttle/heavy loads/cold engine, the computer will ignore the O2. The higher the mixture (1.5) you have a lean mixture.
CONDITION
Part throttle cruzing under light load - The air/fuel mix should be optimal at 14.7 to 1. Your O2 signal will be 1.0 volts at 14.7 to 1.
Full throttle, heavy load - The A/F mix should be around 11.5/1. Your O2 signal will be around 0.8 volts.
Closed throttle, decelleration - The A/F mix will be around 21/1. The O2 signal will be around 1.5 volts.
The lower the O2 sensor voltage (.05) the richer the mixture. When you see low voltages, your O2 sensor is asking the engine management to lean out the mixture. Under full throttle/heavy loads/cold engine, the computer will ignore the O2. The higher the mixture (1.5) you have a lean mixture.
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Originally Posted by Bill
Optimally tuned during closed loop? This varries under operating conditions.
CONDITION
Part throttle cruzing under light load - The air/fuel mix should be optimal at 14.7 to 1. Your O2 signal will be 1.0 volts at 14.7 to 1.
Full throttle, heavy load - The A/F mix should be around 11.5/1. Your O2 signal will be around 0.8 volts.
Closed throttle, decelleration - The A/F mix will be around 21/1. The O2 signal will be around 1.5 volts.
The lower the O2 sensor voltage (.05) the richer the mixture. When you see low voltages, your O2 sensor is asking the engine management to lean out the mixture. Under full throttle/heavy loads/cold engine, the computer will ignore the O2. The higher the mixture (1.5) you have a lean mixture.
CONDITION
Part throttle cruzing under light load - The air/fuel mix should be optimal at 14.7 to 1. Your O2 signal will be 1.0 volts at 14.7 to 1.
Full throttle, heavy load - The A/F mix should be around 11.5/1. Your O2 signal will be around 0.8 volts.
Closed throttle, decelleration - The A/F mix will be around 21/1. The O2 signal will be around 1.5 volts.
The lower the O2 sensor voltage (.05) the richer the mixture. When you see low voltages, your O2 sensor is asking the engine management to lean out the mixture. Under full throttle/heavy loads/cold engine, the computer will ignore the O2. The higher the mixture (1.5) you have a lean mixture.
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The O2 readings I posted are the readings I see from my Zeitronics using a wide band O2 and not a narrow band O2.
Perhaps I confused the issue. I deffinately do not want to cause anyone engine damage. Thanks for your comments Jeremy.
Perhaps I confused the issue. I deffinately do not want to cause anyone engine damage. Thanks for your comments Jeremy.
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Originally Posted by Bill
The O2 readings I posted are the readings I see from my Zeitronics using a wide band O2 and not a narrow band O2.
Perhaps I confused the issue. I deffinately do not want to cause anyone engine damage. Thanks for your comments Jeremy.
Perhaps I confused the issue. I deffinately do not want to cause anyone engine damage. Thanks for your comments Jeremy.
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Originally Posted by michael2e
Anybody? How about you guys with the SMT6? My research and trials suggests an optimal tuning results in 0.88 volts coming out of the O2 sensor during closed loop acceleration.
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Originally Posted by Bill
The lower the O2 sensor voltage (.05) the richer the mixture. When you see low voltages, your O2 sensor is asking the engine management to lean out the mixture. Under full throttle/heavy loads/cold engine, the computer will ignore the O2. The higher the mixture (1.5) you have a lean mixture.
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The voltage will be bounching back and forth between 0.6 and 0.2 volts in closed loop. The engine controller (DME) is making the mixture a little rich then lean centered around 14.7/1 to allow for the proper operation of the cat.
Below is a graph that shows the amount of change in the output voltage of a NB with exhaust gas temperature changes. The changes are large in the rich side of the curve ( 10-14.7) were you want the AFR to be under boost.
Below is a graph that shows the amount of change in the output voltage of a NB with exhaust gas temperature changes. The changes are large in the rich side of the curve ( 10-14.7) were you want the AFR to be under boost.
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Mike, I included a O2 voltage table in the SMT6 install which you should have. In closed loop, you will notice the AFR hovering between 14 and 15:1 AFR.
Tom, I'm not sure if you are logging the Wideband signal, if so, would you compare the results to the values in the O2 table?
Tom, I'm not sure if you are logging the Wideband signal, if so, would you compare the results to the values in the O2 table?
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Originally Posted by fast951
Tom, I'm not sure if you are logging the Wideband signal, if so, would you compare the results to the values in the O2 table?
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