O2 sensor and fuel trim readings help?
08-12-2016, 08:02 AM
#1
O2 sensor and fuel trim readings help?
Guys i have run a scan on my 05 C6 and all looks pretty good, minor codes for HVAC but i knew that.
A couple of things i need some advice on though.
No codes or check light but STFT are ok down around 0/-+2
but LTFT are always down around -4/5 so a rich condition i guess but not to major.
But my HO2's are showing b1 sens1 switching around 700mv down to 65 fluctuating
b2 sens 1 switching between 750/800mv down to 50mv fluctuating
so a little on the rich side again i think
But what i'm a little unsure of is both b1 sens 2 and b2 sens 2 are fixed around 650/750mv not switching......
Is it normal for downstream no 2 sensors to stay fixed and are those numbers quite high?
No mods except for a Vararam intake,
Thanks in advance
Last edited by mazzerman; 08-12-2016 at 08:13 AM.
08-12-2016, 09:51 AM
#2
Drifting
Your downstream sensors will stay more steady. It means your catalyst is working. If both up & downstream were tracing the same, your cats are shot (or gutted, lol).
The trims may be compensating for the intake a bit.
The trims may be compensating for the intake a bit.
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mazzerman (08-12-2016)
08-12-2016, 10:01 AM
#3
Would be interesting to know if other folk have similar figures....
08-12-2016, 10:54 AM
#4
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St. Jude Donor '15
Normal O2 cycling for the fronts. It doesn't matter exactly where they end up. The point is they "switch" back and forth between rich and lean. All you can tell with narrowband O2 sensors is it's leaner than 14.7:1 (i.e. < 450 mv) or richer than 14.7:1 (i.e. > 450 mv). The exact degree is not something you can tell with any real accuracy with this type of O2 sensor.
It constantly swings back and forth between slightly rich and slightly lean. This is by design.
Fuel trims being those values doesn't mean it's rich or lean. It means it's having to adjust fueling by that % to make it NOT rich or lean. Those values are quite small. Nothing to worry about.
Not a clue on the rear O2 sensors--wouldn't worry about it though unless you're having issues.
Overall, nothing to worry about.
It constantly swings back and forth between slightly rich and slightly lean. This is by design.
Fuel trims being those values doesn't mean it's rich or lean. It means it's having to adjust fueling by that % to make it NOT rich or lean. Those values are quite small. Nothing to worry about.
Not a clue on the rear O2 sensors--wouldn't worry about it though unless you're having issues.
Overall, nothing to worry about.
Last edited by schpenxel; 08-12-2016 at 10:54 AM.
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mazzerman (08-12-2016)
08-12-2016, 11:03 AM
#5
Normal O2 cycling for the fronts. It doesn't matter exactly where they end up. The point is they "switch" back and forth between rich and lean. All you can tell with narrowband O2 sensors is it's leaner than 14.7:1 (i.e. < 450 mv) or richer than 14.7:1 (i.e. > 450 mv). The exact degree is not something you can tell with any real accuracy with this type of O2 sensor.
It constantly swings back and forth between slightly rich and slightly lean. This is by design.
Fuel trims being those values doesn't mean it's rich or lean. It means it's having to adjust fueling by that % to make it NOT rich or lean. Those values are quite small. Nothing to worry about.
Not a clue on the rear O2 sensors--wouldn't worry about it though unless you're having issues.
Overall, nothing to worry about.
It constantly swings back and forth between slightly rich and slightly lean. This is by design.
Fuel trims being those values doesn't mean it's rich or lean. It means it's having to adjust fueling by that % to make it NOT rich or lean. Those values are quite small. Nothing to worry about.
Not a clue on the rear O2 sensors--wouldn't worry about it though unless you're having issues.
Overall, nothing to worry about.
