A Biased O2 Sensor
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From: North Texas, born in London.
A Biased O2 Sensor
During routine maintenance on a 1998 F150, I changed out both front O2 sensors. Just for grins, or because I am an engineer, I took the senor to an environmental lab to test response time and bandwidth. The driver’s side sensor indicated no abnormalities, except response time was a little slow (52K miles) compared to new one. When I placed the passenger’s side O2 sensor into the chamber, the scope showed a slow oscillation (+/- 100mV) around .62 volts. This is with out changing the atmosphere. To verify setup, I changed back to the driver’s side and new O2 sensors and obtained the previously recorded same “normal” responses. Placed the passenger’s side back in the chamber and the oscillation reappeared. In addition, in a 30% O2 atmosphere, the sensor would output only .878 volts. Called Bosch and they requested I send them the data and sensor for evaluation. Finally, I do not know when the O2 sensor failed, and there were no codes. Once the O2 sensors were changed, the mpg went for about 11 mpg to 14 mpg.
Last edited by Chrishulgan; Jul 6, 2005 at 02:24 PM. Reason: sp
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Interesting, but not being a certified injun-ear I don't fully grasp your post. 
On a related note my buddy an I worked on his 98 Scab (4.6) this weekend. Fresh oil and a IAC cleaning, TB elbow cleaning etc netted him 16mpg on the road insead of 12 or worse. He needs to get the P0420 code fixed though.
On a related note my buddy an I worked on his 98 Scab (4.6) this weekend. Fresh oil and a IAC cleaning, TB elbow cleaning etc netted him 16mpg on the road insead of 12 or worse. He needs to get the P0420 code fixed though.
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From: Bakersfield, CA, USA
Thanks for the info!
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
Last edited by dirt bike dave; Jul 6, 2005 at 02:42 PM.
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Originally Posted by PONY_DRIVER
Interesting, but not being a certified injun-ear I don't fully grasp your post.
On a related note my buddy an I worked on his 98 Scab (4.6) this weekend. Fresh oil and a IAC cleaning, TB elbow cleaning etc netted him 16mpg on the road insead of 12 or worse. He needs to get the P0420 code fixed though.
On a related note my buddy an I worked on his 98 Scab (4.6) this weekend. Fresh oil and a IAC cleaning, TB elbow cleaning etc netted him 16mpg on the road insead of 12 or worse. He needs to get the P0420 code fixed though.
It is information relating to what I assume was a defective sensor, although the ECM said otherwise. If had taken the “no code” route and not changed the sensors, then probably the gas mileage would have at least remained the same or become worse over a period. On reflection, the messages is change the O2 sensors periodically, codes or not IMHO.
"On a related note my buddy an I worked on his 98 Scab (4.6) this weekend. Fresh oil and a IAC cleaning, TB elbow cleaning etc netted him 16mpg" Thanks for the info. I try the same this coming weekend. Every little bit helps.
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Old, but Gold
Originally Posted by dirt bike dave
Thanks for the info!
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
Cheers…
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Apology
Originally Posted by dirt bike dave
Thanks for the info!
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
'Old-school' types like me are starting to figure out the tricks we need to keep these newer vehicles running properly. I recently replaced the O2 sensors on my truck in an attempt to restore some of the lost mileage and performance (it has 95,000 miles now and has really lost a lot of zip and mpg over the last six months). The new sensors helped restore some of my missing power and mileage, but not as much as I'd hoped. It was an easy job, too, with the right socket.
I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?
FWIW, I have not read codes from the computer, but I have never had a CEL.
Please accept my apology. I misread your question. You state: “I still have my old sensors - are there any simple tests I can do at home with a volt/ohm meter to see if the old ones were still within spec?”. I am unaware of any simple test that will provide dynamic testing on the sensors. I have access to an environmental lab where I am able to bring the O2 sensors up to operating temperature where testing is most accurate. Some one else in the forum may have a test. I am sorry, but I do not.
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From: Easton, Pa.
First, you never test their resistance because the meter has a battery in it that will wreck the sensor.
The sensors are voltage generating devices.
You can get an indication of there activity by the 'back yard method' of measuring their output when heated with a propane torch.
The sensors are voltage generating devices.
You can get an indication of there activity by the 'back yard method' of measuring their output when heated with a propane torch.
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Agreement
Originally Posted by Bluegrass
First, you never test their resistance because the meter has a battery in it that will wreck the sensor.
The sensors are voltage generating devices.
You can get an indication of there activity by the 'back yard method' of measuring their output when heated with a propane torch.
The sensors are voltage generating devices.
You can get an indication of there activity by the 'back yard method' of measuring their output when heated with a propane torch.
I concur completely with you regarding the O2 sensors are voltage-producing devices only. To measure the voltage using the scope I had to use the 10X probe to reduce loading.