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Discussion Starter · #1 ·
I was fiddling with my new Ulktra Gauge and found there are two active O2 sensors.

Does my Base Solstice even have two O2 sensors ?

When I displayed the graphs one seemed to be erratic.



The Ultra Gauge Manual has the following on these sensors.



The Ultra Gauge did not list ant DTC or pending DTC.

Additional info on this issue(?) is more than welcome
 

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AFAIK pretty much all modern cars have 2 x O2 sensors. One before the cat and one in or after it. It allows the ECM to adjust to how well the cat is operating. In our case we have a wideband O2 before the cat (IIRC) and a narrow band in it.
 

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Discussion Starter · #3 ·
Thanks TS. Is the "erratic" graph something I should be worried about ?

I checked the Ulrta Gauge Wideband O2 sensors and they are all inactive.

Below the whole list of Ultra Gauge sensors for my Solstice. As you can see 2 are active



Below what the user manual has to say about the Wide Band O2 sensor.

 

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I am not an expert on this, but a quick google pulled up the following: (Troubleshooting Wideband O2 Sensors)

Looks like the graph on the left is your narrowband sensor (AKA: all is cool)

Many late-model imports such as Honda, Toyota, Volkswagen and others use “Air/Fuel” (A/F) sensors rather than conventional oxygen (O2) sensors to monitor the exhaust gases coming out of the engine. What’s the difference? An air/fuel sensor can read a much wider and leaner range of fuel mixtures than a conventional O2 sensor. That’s why they’re also called “wideband” O2 sensors.

Another difference is that A/F sensors don’t produce a voltage signal that suddenly changes on either side of Lambda when the air/fuel goes rich or lean. A conventional O2 sensor will produce either a rich reading (0.8 volts) or a lean reading (0.2 volts) when the fuel mixture changes. An A/F sensor, by comparison, produces a changing current signal that varies in direct proportion to the amount of unburned oxygen in the exhaust.
 

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The front O2 is seeing the direct results of combustion. It sees the firing pulses of the engine as individual spikes. The nice smooth curve on the back end is good.

LOL

Find something else to worry about my friend.
 

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In our case we have a wideband O2 before the cat (IIRC) and a narrow band after it.
Only the GXP's have a wideband, the 2.4's only have narowband.
 

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I just looked up the O2 sensors for a friends 2.4 and the parts catalog showed two O2 sensors.

Red has data from two sensors from his 2.4
 

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They both do have two, what he said was that the 2.4 has two narrow band, the 2.0 has one wide and one narrow band.
 

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Discussion Starter · #11 ·
The front O2 is seeing the direct results of combustion. It sees the firing pulses of the engine as individual spikes. The nice smooth curve on the back end is good.

LOL

Find something else to worry about my friend.
Thanks Rob. I am glad this is normal.

But why should one see the individual pulses ? The engine is idling at 830 RPM. So the graph should be on fat blob of white between 0.1 and 0.8 :)
 

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I do not think those are individual exhaust pulses, I think they are the short-term fuel trim working back and forth around the target value
 
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