Folks,
I've been getting the P0420 and P0430 "Catalytic System efficiency below threshold" codes for both banks. I've reset it a few times but it comes back after 50-60 miles. I've changed all 4 O2 sensors (my 100 has around 168k miles so thought it would be a good idea in any case). I've also cleaned the MAF sensor but no change. I had installed the EMSPowered exhaust (not the midpipes) last year as the outer cover of my muffler had peeled off.
I have an OBD Bluetooth device connected so can see real-time values on the Torque app on my android ph. I read that the waveforms of the post cat O2 sensor volts should be relatively flat where as the Pre cat ones would be wavy. I'm finding both sets to be wavy on both banks.
From whatever I've read, both Cats failing at the same time is rare - or indicates some upstream problem. I'd like to figure out whether I have an upstream problem and/or whether the Cats have failed. I can look at the fuel trim and other real-time info on the scanner - but what should I be looking for? What else should I be doing in terms of diagnostics?
Lastly, anyone have good experience with any aftermarket Cats on the 100s? The OEM ones are for over $1200 a piece. I saw one direct fit from Magnaflow - any other I should consider?
I've been getting the P0420 and P0430 "Catalytic System efficiency below threshold" codes for both banks. I've reset it a few times but it comes back after 50-60 miles. I've changed all 4 O2 sensors (my 100 has around 168k miles so thought it would be a good idea in any case). I've also cleaned the MAF sensor but no change. I had installed the EMSPowered exhaust (not the midpipes) last year as the outer cover of my muffler had peeled off.
I have an OBD Bluetooth device connected so can see real-time values on the Torque app on my android ph. I read that the waveforms of the post cat O2 sensor volts should be relatively flat where as the Pre cat ones would be wavy. I'm finding both sets to be wavy on both banks.
From whatever I've read, both Cats failing at the same time is rare - or indicates some upstream problem. I'd like to figure out whether I have an upstream problem and/or whether the Cats have failed. I can look at the fuel trim and other real-time info on the scanner - but what should I be looking for? What else should I be doing in terms of diagnostics?
Lastly, anyone have good experience with any aftermarket Cats on the 100s? The OEM ones are for over $1200 a piece. I saw one direct fit from Magnaflow - any other I should consider?
