Quote:
Originally Posted by jimmylomax
I'm not doubting or questioning the source of the cat efficiency losses. I guess I'm questioning the detection. I am wondering if the reason mine hasn't been throwing P0420 is because it takes at least 15 minutes of running without an engine restart for the OBD diagnostic to perform and fail the test before throwing the trouble code. I threw my OBDII scanner on yesterday and graphed my downsteam O2 and it seems clear to me I do in fact need to give whiskers a bath of acid. Here is a plot at steady load and speed at 60mph showing my downstream O2 all over the place (which I believe in indicate of a poorly functioning catalytic converter... EricMyCarguy indicated it should hold flat at 0.5v meaning o2 inside and outside exhaust is 1:1)
RE: measuring exhaust temp, I don't think most cars have that sensor - I meant with an infrared handheld gun.
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I think these are pretty interesting points and I think I will put the downstream O2 disply onto my UltraGauge on the dashboard. I am pretty sure mine jumps around too. But I am not surprised, since the car passess smog but is not as clean as new. Clearly, my unit is within tolerances tho not optimal.
My moments when the CEL has returned, and generally whenever it showed up, were NOT during EOC. They were after significant stretches of steady throttle. I do more of that in recent years on freeways than once upon a time because I have a 0.710 fifth, 3.25 FD, 15" rims (12 lbs), and 175/70-r15 tires... so it cruises flat ground getting remarkable FE... not much benefit to EOC in such conditions.
