Faulty O2 sensor?
09-13-2012, 12:46 PM
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Faulty O2 sensor? I recently scanned one of the first few startups of my finished setup - 5.3 turbo/T56. In observing my O2 voltages, I noticed that B1S1 and B2S1 were reporting vastly different values. B2S1 averaged roughly 900mv at idle whereas B1S1 averaged between 150-300mv at idle. Is one of these sensors faulty? If so, which one?
Thanks for the input. Still learning here. I can post the scan tonight when I get home if needed.
Thanks for the input. Still learning here. I can post the scan tonight when I get home if needed.
09-14-2012, 10:43 AM
#3
Easy... switch them and scan again. If the readings follow the sensor it is bad. If they stay the same, you have another issue and both sensors may be good.
Don't buy new sensors until you do more testing, many times they are fine
Don't buy new sensors until you do more testing, many times they are fine
09-14-2012, 12:32 PM
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I will post the log tonight when I get home. Which one would be faulty, the low values? what is the operating range of a working O2 sensor, rich to lean? Thanks
09-14-2012, 02:53 PM
#5
An operating oxygen sensor will switch between about ~100 and ~800mv as the computer crosses back and forth across stoich (14.63ish:1 AFR). I personally get my cars to idle in the lower mv range (leaner) to reduce exhaust fumes.
Usually a bad O2 sensor sits still at a certain mv or makes odd switches. Basically if the sensor stays below 100 or above 800 for an extended period of time, depending on your tune, you usually have a problem. In most Open Loop, Speed Density tunes, O2 sensors are ignored. For a MAF tune, they are used to adjust fuel through LTFTs or STFTs. I have seen slow to switch O2s cause issues too. Until you post a log, its just a guess though.
Usually a bad O2 sensor sits still at a certain mv or makes odd switches. Basically if the sensor stays below 100 or above 800 for an extended period of time, depending on your tune, you usually have a problem. In most Open Loop, Speed Density tunes, O2 sensors are ignored. For a MAF tune, they are used to adjust fuel through LTFTs or STFTs. I have seen slow to switch O2s cause issues too. Until you post a log, its just a guess though.
