Timeline for Shouldn't my post-cat O2 sensors (lambda probes) be reporting varying numbers?
Current License: CC BY-SA 3.0
20 events
| when toggle format | what | by | license | comment | |
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| Feb 16, 2017 at 2:49 | answer | added | user25936 | timeline score: 0 | |
| Sep 28, 2016 at 8:26 | comment | added | Zaid | Re: "the probes pre-cat are varying substantially" what is the range of voltage output you see? | |
| Sep 26, 2016 at 22:37 | comment | added | andrewb | @Zaid agreed, though I suspect it's warm vs hot idle. I can run the readings again under a cold/warm idle if that's helpful at all. | |
| Sep 26, 2016 at 12:49 | comment | added | Zaid | Thanks, will take a look at it later this evening. Things look a bit different than a couple of weeks ago for sure | |
| Sep 26, 2016 at 12:38 | comment | added | andrewb | @Zaid done as requested, at hot idle | |
| Sep 26, 2016 at 12:35 | history | edited | andrewb | CC BY-SA 3.0 |
Removed superfluous headings on readings
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| Sep 16, 2016 at 9:28 | history | tweeted | twitter.com/StackMechanics/status/776714462715863040 | ||
| Sep 15, 2016 at 20:31 | answer | added | Zaid | timeline score: 5 | |
| Sep 15, 2016 at 13:32 | comment | added | Zaid | Could I trouble you to get a screenshot of the Analog 1 page as well? It should look something like this | |
| Sep 15, 2016 at 13:26 | comment | added | Zaid | By hot idle I meant that the engine's reached steady operating temperature. A small correction to make - rich voltages should be closer to 0.9 V. | |
| Sep 15, 2016 at 13:01 | comment | added | andrewb | @Zaid How would you define "hot idle"? | |
| Sep 15, 2016 at 12:59 | comment | added | andrewb | Interesting, so it might be behaving correctly then? I had been idling the engine for about 5 minutes or so when I took the screenshots, so not cold, but not after a proper drive. | |
| Sep 15, 2016 at 12:56 | history | edited | andrewb | CC BY-SA 3.0 |
added lambda integrator readings; added 105 characters in body
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| Sep 15, 2016 at 12:56 | comment | added | Zaid | Also, I think the O2 heaters are active. Were these readings taken with the car just started or at hot idle? Hot idle, Analog 2 should give a more complete picture of what's going on | |
| Sep 15, 2016 at 12:55 | history | edited | andrewb | CC BY-SA 3.0 |
added year
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| Sep 15, 2016 at 12:53 | comment | added | Zaid | The pre-cats should vary between 0.1 and 0.9 V, that is expected. The post-cats should be stable and read slightly richer (closer to 0.1 V). Are you confident you selected the right engine for your E46? It's just that I'm not used to seeing INPA setup to show pre-cat O2's on the left and post-cats on the right side. | |
| Sep 15, 2016 at 12:51 | answer | added | SteveRacer | timeline score: 3 | |
| Sep 15, 2016 at 12:51 | comment | added | Dalton D | Actually, it depends on the year of your BMW. In early OBD-II systems the post-cat o2 sensor signal hardly fluctuated (if at all). They weren't actually meant to monitor the fuel control. Instead they were only meant to monitor the efficiency of the catalytic converter. See here autodiagnosticsandpublishing.com/feature/o2-sensor-testing.html | |
| Sep 15, 2016 at 12:49 | comment | added | Ben | that seems pretty close to a reference voltage. check your wiring first. on a working rear o2 at operating temp i'd expect around .7v at idle. the waveform shouldn't switch like a front non-afr sensor would. | |
| Sep 15, 2016 at 12:25 | history | asked | andrewb | CC BY-SA 3.0 |
