Question Strange behavior of O2 sensor
- Thread starter LFMarm
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If you switched sensors and the problem continued, I would assume it is the wiring / molex connector.
[Added : I hadn't read all of the threads and just realized that you had already replaced the wiring. Very odd].
- brett
[Added : I hadn't read all of the threads and just realized that you had already replaced the wiring. Very odd].
- brett
SavageSeaCow
Contributor
I have had this issue twice recently and both times it was caused by a pin in the molex on the rebreather side actually breaking because of corrosion. I assume the intermittent nature is the slight movement of the pin pieces separating and then coming together with shifts in position. When the issue is constant I’m more inclined to hit it with the deoxit but when it’s intermittent there is probably a mechanical aspect too.
I had a similar issue on my Kiss Spirit. Had a single sensor suddenly drop to about 1/2 the expected reading while diving. If I changed orientations it would come back to full reading in line with the other 2 sensors (most of the time).
After disassembling the unit I 'played' with the wire harness and could replicate the issue if the right combination of sensor tilt and wire bend was held. Deoxit did help temporarily, but the issue returned. I also tried moving the position of the sensor...and the issue returned on that same sensor.
I do have a theory that the electrolyte was drying up a bit, so it would shift around and not fully cover the deteriorating anode when in certain orientations. I'd see the drop when in trim (so the sensor was 'sideways') and the issue would almost always disappear when I went vertical (membrane down, connector up). I did do this 'trick' a few times on 2 or 3 shallow dives before the orientation change wouldn't reliably get it back. At that point I concluded it was a non-recoverable sensor issue and replaced it. The sensor was getting near a year of use and a month or two away from the factory 'use by date'.
Two examples of the behavior are below (2 seperate dives).
After disassembling the unit I 'played' with the wire harness and could replicate the issue if the right combination of sensor tilt and wire bend was held. Deoxit did help temporarily, but the issue returned. I also tried moving the position of the sensor...and the issue returned on that same sensor.
I do have a theory that the electrolyte was drying up a bit, so it would shift around and not fully cover the deteriorating anode when in certain orientations. I'd see the drop when in trim (so the sensor was 'sideways') and the issue would almost always disappear when I went vertical (membrane down, connector up). I did do this 'trick' a few times on 2 or 3 shallow dives before the orientation change wouldn't reliably get it back. At that point I concluded it was a non-recoverable sensor issue and replaced it. The sensor was getting near a year of use and a month or two away from the factory 'use by date'.
Two examples of the behavior are below (2 seperate dives).
Very interesting. I just wonder now if I happened to test 2 sensors both showing the same issue. More testing needed.
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