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Hey guys. Something that I've always felt about my G37 is that it's a lot quieter than other G37s that I've driven and sat in. In fact, it's gotten so quiet over time that I just about want to say my cats are clogged. Reading the live data on my scan tool, not only do the rear O2 sensors not flucuate(they remain at 0.280V), but the CATEMP readings both read 0. On top of that, any time I go WOT, I get a burning smell that comes through my AC vents. I will attach a photo of the O2 sensor and CATEMP dataset. Does this appear like my cats are clogged?
That’s not a great method to check, but your rear 02s should move, but they will move a lot slower than the front ones.
Best way to check is by actually inspecting the inside of them with a boroscope through the front 02 sensor hole.
Another way of testing is a good 5-10 minutes of hardcore driving should yield some glowing cats. You should be registering catalytic temps either way and these are located in the A/F sensor(pre cat).
Another way of testing is a good 5-10 minutes of hardcore driving should yield some glowing cats. You should be registering catalytic temps either way and these are located in the A/F sensor(pre cat).
The FSM says that the A/F sensor should read approximately 2.2V, which they both are, but since the cat temps aren't being read correctly, does this mean both my A/F sensors are bad?
The FSM says that the A/F sensor should read approximately 2.2V, which they both are, but since the cat temps aren't being read correctly, does this mean both my A/F sensors are bad?
I confirmed that the sensors read temperature so it's a possibility, I do notice the FSM doesnt talk about the cat temp diagnosis.
One of the things you could do is loosen both sensors and with the car on, carefully unscrew them bit by bit.
You should see I believe higher voltages as it unscrews since it should detect higher oxygen content.
Slower responses to these voltages is what you want when you delete cats to avoid a CEL.
At the same time bad sensors might act lazy as well. FYI
Two easy ways to check for plugged catalytic converters:
• Do a few wide open throttle runs, all the way to 7,000 RPM. Does it have the same acceleration? If it does, then the are probably OK.
• Look/record your MAF data while doing the wide open throttle test. If should be more than 250 g/s or 108 lbs/min
Also, if your scanner can't read/update the display quickly, you won't see some/all of the quick changes.
Bottom line: If you don't have any codes, your cats are good CARB/EPA have made sure of that.
Now, go for a nice drive and enjoy your G
Does this look like clogged cats?
