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I know (well, pretty sure) that the passenger side O2 sensor is dead, as you can see in the data below. My question is "Does Bank 1 O2 sensor look OK, or is it dying?"
Your upstream O2 sensors “oscillate” between 200-800 mv’s if functioning correctly…the downstreams remain fairly constant between 600-700mv’s or so…your bank 2 sensor looks bad but it can be a wiring issue…if “stuck” low like that your PCM will be adding fuel because it thinks that bank is running lean…if you disconnect the sensor and you see 450mv’s (bias voltage) on the scan tool key on your wiring is fine.
Thanks. What about the Bank 1 sensor? I have really good activity for s little less than 5 minutes, then it suddenly goes high-ish, with periods of activity much more sporadic. Driving during this time was on a rural highway with normal traffic.
You’re probably using a cheap code reader to graph your upstream O2’s but the (blue) bank 1 sensors appears it is oscillating between 200-800mv’s…instructional video below you should watch…also a screenshot of my O2 sensors.
You’re probably using a cheap code reader to graph your upstream O2’s but the (blue) bank 1 sensors appears it is oscillating between 200-800mv’s…instructional video below you should watch…also a screenshot of my O2 sensors.
First off, thanks for the suggestion about unplugging the Bank 2 sensor and isolating the problem to the wiring or sensor; I'll do that tomorrow when I get home from work tomorrow.
Second, you're correct about using a cheap scan tool; it's served me well so far, but I know it has limits. I've attached a more "zoomed in" snapshot. Based on what I learned in the 1st part of that video you linked (thanks for that!), assuming my wiring's OK, I need to replace both O2 sensors. One because it's dead, the other because it's erratic and has periods where it goes comatose. Again, that's assuming my wiring is OK.
Or do I need to do something else? Also, is the fact that these O2 sensors are originals with almost 300k miles on them any factor?
Thanks again for all the help, and have a good one,
Mike
FYI, disconnected the O2 sensors, flat lined at 0.445 volts, so the harness looks to be OK.
Question: Is it OK to run the engine for a few thousand in-town miles with the O2s disconnected? I'm going to retire in May '24, and my plan is go through my C5 top to bottom, front to back, starting with a complete refresh of the near 300k mile engine. I think I'm beginning to burn some oil (she's leaking from the upper oil pan gasket and everything is a mess) and don't want to mess up a new set of sensors.
NO !!…not a good idea to run with the sensors disconnected because the upstreams control your fuel scheduling…the engine will then run in “open loop” and rely on other engine sensors…not a good idea !!
NO !!…not a good idea to run with the sensors disconnected because the upstreams control your fuel scheduling…the engine will then run in “open loop” and rely on other engine sensors…not a good idea !!
Fair enough; I figured you'd give me the right direction. And if both sensors foul out, well, that's not that expensive compared to an engine refresh.
Replaced my failed O2 sensor today, and this is typical of what my O2s were looking like on my test drive, nice and busy! The failed sensor appears to be full of soft carbon, but that could have been either the cause of the failure or a result of the failure (and bank 2 running really rich). In any case, she's back on the road!
O2 Dead, Dying, or OK?
