O2 Sensor Voltages
Thread Starter
Launching!
Joined: Nov 2002
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From: Freehold, NJ
O2 Sensor Voltages Why is it that when an O2 sensor is used in a wide band dyno the measured A/F ratio is said to be accurate but when you read your real O2 voltages the consensus appears to be that it is not accurate?
Isn't an O2 sensor an O2 sensor.. Whether it is feeding a wide band a/f guage or a PCM it's still sending a voltage signal to some receiving device based on the amount of O2 present (or not present) in the exhaust stream.
I just don't understand why this signal isn't usable.
I found this link to a home made wide band sensor using a stock Honda O2 sensor.. Is a Honda O2 sensor special? Is it a better sensor the the stock GM sensor?
This is also a very informative site on O2 sensors (I think someone posted it here..
Isn't an O2 sensor an O2 sensor.. Whether it is feeding a wide band a/f guage or a PCM it's still sending a voltage signal to some receiving device based on the amount of O2 present (or not present) in the exhaust stream.
I just don't understand why this signal isn't usable.
I found this link to a home made wide band sensor using a stock Honda O2 sensor.. Is a Honda O2 sensor special? Is it a better sensor the the stock GM sensor?
This is also a very informative site on O2 sensors (I think someone posted it here..
TECH Addict
Joined: Jul 2002
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This may help...remember when reading Oxygen Sensor = narrow band O2 - old style and also A/F Ratio Sensor = Wideband O2 sensor . This is a GREAT site: AutoShop 101
Go to -> Tech Articles -> 37 Sensors #6 Oxygen / Air Fuel Sensors.
Very Informative stuff!
joel
Go to -> Tech Articles -> 37 Sensors #6 Oxygen / Air Fuel Sensors.
Very Informative stuff!
joel
In the region of interest (for WOT power tuning)
the output voltage depends more on temperature
than AFR. Without knowing the sensor temp, you
know little more than "richer than stoich". In the
attached .gif you can see that 0.90V can be
anywhere from 13.7:1 (500C) to ~9:1 (900C).
We don't have a very good idea of EGT for stock
vehicles, let alone various header configurations,
and there is plenty of variation with engine compartment
airflow, time-at-high-output, etc. to push the EGT in
downstream locations around.
The fancy wideband sensors control element temp
to make better measurement possible. The cheapos
(OEM) don't.
the output voltage depends more on temperature
than AFR. Without knowing the sensor temp, you
know little more than "richer than stoich". In the
attached .gif you can see that 0.90V can be
anywhere from 13.7:1 (500C) to ~9:1 (900C).
We don't have a very good idea of EGT for stock
vehicles, let alone various header configurations,
and there is plenty of variation with engine compartment
airflow, time-at-high-output, etc. to push the EGT in
downstream locations around.
The fancy wideband sensors control element temp
to make better measurement possible. The cheapos
(OEM) don't.
