Hi there guys, my car has a high knox i believe that is what they called it. it blew 3 times the amount of - NO PPM that it could. 1246. I just recently swapped the exhaust back to stock from long tubes. I threw a code P1133 which is bank 1 sensor1 driver front 02 sensor i changed the sensor and unhooked the battery for 1 hour and i started the car and the ses light is still on. How can i fix this and could this be the reason i am not passing smog ? The car was great before i swapped it back to stock exhaust.
thank you.

 

what other mods do you have?

 

Is 1 hour long enough to reset the PCM? I'd try resetting it by pulling the fuses with the key on method and see what happens. P1133 is supposed to illuminate the MIL on the second consecutive ignition cycle it sees a failure. Note: All the readiness tests will be reset too, so you'll need some miles/drive cycles on the car before bringing it back in for inspection, unless they're just doing the sniffer.

 

NOX is formed when combustion temps exceed 2500 deg. If I remember correctly from my previous life, as an emissions repair tech. You should be on the verge of pinging. I take it those readings where at cruise on a dyno? Do you tune it yourself? If you do take some timing out of it where they run it for the test.
PS Thats the whole purpose in life for an EGR system. To lower combustion temp and therefore reduce NOX.

 

I only have a lid k&n 160t catback etc. I only got the fans tuned and my shift points raised ands my rear 02's deleted. No i didnt tune it myself. Yeah i guess i have only driven the car 250 miles since i got the new clutch in it and with the stock exhaust. but everything was great before i put the stock exhaust back on it. Im so confused.

 

I had High Nox in my 92 camaro, my timeing (sp?) was off... could be your prob..

 

I dont think you can clear the code by pulling the fuses.It has to be cleared with a scanner.
The 02 failure probably isnt the cause of the hi NOX. Unless its leaning that bank pretty bad. It almost always caused by too much timing and/or an inoperative EGR system. In your case its probably removed, right?
First fix the code. Then scan it to see if the fuel trims are in line.
Then have your tuner take about 1.5 or 2 degrees of timing out of it where they test it. Light load, RPM/MAP. In the timing tables there's alot more timing dialed in under light load than there is under WOT.

 

Yeah high NOx is likely too lean. Check your AFR if possible. Log o2mv as a guesstimate.
Yeah as edcmat-l1 says might be too much timing.

Maybe flash a stock tune in to pass dependent on your mods.