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Tonyrodz
Resident Resident
New one installed--This seem better?
Tonyrodz's Tahoe Build Thread
- Thread starter Tonyrodz
- Start date
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Same as before, we don't need the Heater amp lines right now, need to scroll down to show both non-heater Bank x Sensor 1 readings. But if you can scroll down one line we should see one Heater value and both O2 mV readings on one screen.
Some good basic info on the sensors and fuel trims can be found here:
https://www.autoserviceprofessional.com/articles/7599-easy-air-fuel-and-oxygen-sensor-diagnosis
Excerpt:
https://www.autoserviceprofessional.com/articles/7599-easy-air-fuel-and-oxygen-sensor-diagnosis
Excerpt:
The oxygen sensor measures the amount of oxygen in the exhaust that is used in the combustion process.
For pre-catalytic converter oxygen sensors used for fuel control:
Less oxygen than optimal in the exhaust results in a signal voltage over 450 mV. This reflects a RICH CONDITION. More oxygen in the exhaust than optimal results in a signal voltage under 450 mV. This reflects a LEAN CONDITION.
Good oxygen sensors have even waves in the 150 mV to 850 mV range while ascending or descending within a 100 mS or less when the system is in closed loop.
For post-catalytic converter oxygen sensors used for fuel control:
Post-cat oxygen sensors, when good, feature a steady voltage usually between 500 to 700 mV. If it zigzags, the catalytic converter is highly suspect.
On some vehicles the rear sensor does have some effect on fuel control. For our purposes, it’s just good to know that when testing the sensor, the voltage should go up when the fuel mixture is rich and should go down when it is lean. Sadly there is no way of generically knowing what is an optimal post-cat oxygen sensor voltage. It differs by the manufacturer.
For pre-catalytic converter oxygen sensors used for fuel control:
Less oxygen than optimal in the exhaust results in a signal voltage over 450 mV. This reflects a RICH CONDITION. More oxygen in the exhaust than optimal results in a signal voltage under 450 mV. This reflects a LEAN CONDITION.
Good oxygen sensors have even waves in the 150 mV to 850 mV range while ascending or descending within a 100 mS or less when the system is in closed loop.
For post-catalytic converter oxygen sensors used for fuel control:
Post-cat oxygen sensors, when good, feature a steady voltage usually between 500 to 700 mV. If it zigzags, the catalytic converter is highly suspect.
On some vehicles the rear sensor does have some effect on fuel control. For our purposes, it’s just good to know that when testing the sensor, the voltage should go up when the fuel mixture is rich and should go down when it is lean. Sadly there is no way of generically knowing what is an optimal post-cat oxygen sensor voltage. It differs by the manufacturer.
Scottydoggs
Full Access Member
this is getting crazy now....ltft are the same as before, but mv look the same now.
im now thinking you have a injector stuck open on that side. smell your oil, see if its got a strong gas smell. sniff the oil on the dip stick.
you could also pull all the plugs on that side and see if one come out wet with gas or stinks of gas.
im now thinking you have a injector stuck open on that side. smell your oil, see if its got a strong gas smell. sniff the oil on the dip stick.
you could also pull all the plugs on that side and see if one come out wet with gas or stinks of gas.
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Tonyrodz
Resident Resident
It figures---I'm done for today. Tomorrow is another day. Funny how shit happens after something else was done.
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Tonyrodz
Resident Resident
The passenger side? So what if I don't smell a strong smell of gas? What else could it be?
After you get it warmed up next time, @Tonyrodz, in addition to the non-heater O2 values, show us the STFTs while it's running. It looks to me like you posted some older pics on that last one. And LTFTs will take some time to adjust after the STFTs are in normal range.
My point is that you showed 0% on both STFT values. If it was running then, in closed loop, eventually the LTFTs will come down to be closer to the STFTs. I think that one was an older pic, or the truck wasn't warmed up and running.
My point is that you showed 0% on both STFT values. If it was running then, in closed loop, eventually the LTFTs will come down to be closer to the STFTs. I think that one was an older pic, or the truck wasn't warmed up and running.
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Tonyrodz
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I just took those pics after installing the new o2. Maybe it needs time to adjust?
I added a little to my last post - please re-read. Take the fuel trim snapshot after it's been warmed up a tad, while it's running.
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