Nissan 370Z Forum - View Single Post

davidyan · 10-31-2010, 11:43 PM

Hi - i have a second car (a 00 Toyota Celica GT-S) that I use as a daily driver. The car recently failed smog twice, and I'm hoping to get some feedback. The car has 170K miles, has a smog certified intake and muffler. No other mods. I recently put on a new O2 sensor, PCV valve and Cat converter (OEM style, not a high-flow).

Anyways the first time in Sept, I failed due to high HC and high NOx - the HC was 181PPM vs. the 64PPM maximum allowed and the NOx was 1734PPM vs. the 477PPM max. Basically, i failed the tailpipe test miserably.

After failing the test, I put in new spark plugs (the other ones were iridium with 95K on it, changed the oil, and cleaned out the fuel system. I even overinflated the tires prior to the test. This is because they put the cars' drive wheels on a dyno type of device to simulate "real driving conditions" up to 2500 RPM. I've heard that by overinflating the tires, you reduce the load a bit which helps reduce the tailpipe results. I even got the car hot by driving high RPM on the freeway to make sure the cat would function well.

Long story short, I failed again - this time only on the HC at 75 PPM vs 64 PPM max - I was much closer to passing the second time.

Since I have a new converter, o2 sensor and everything is functioning properly, I don't know what else to do. Please let me know if you guys have any thoughts.

thanks

10-31-2010, 11:43 PM	#1 (permalink)
davidyan Base Member Join Date: Jun 2009 Location: CA Posts: 244 Drives: PG 370Z Sport 6MT Rep Power: 16	Failed CA Smog Test Twice Hi - i have a second car (a 00 Toyota Celica GT-S) that I use as a daily driver. The car recently failed smog twice, and I'm hoping to get some feedback. The car has 170K miles, has a smog certified intake and muffler. No other mods. I recently put on a new O2 sensor, PCV valve and Cat converter (OEM style, not a high-flow). Anyways the first time in Sept, I failed due to high HC and high NOx - the HC was 181PPM vs. the 64PPM maximum allowed and the NOx was 1734PPM vs. the 477PPM max. Basically, i failed the tailpipe test miserably. After failing the test, I put in new spark plugs (the other ones were iridium with 95K on it, changed the oil, and cleaned out the fuel system. I even overinflated the tires prior to the test. This is because they put the cars' drive wheels on a dyno type of device to simulate "real driving conditions" up to 2500 RPM. I've heard that by overinflating the tires, you reduce the load a bit which helps reduce the tailpipe results. I even got the car hot by driving high RPM on the freeway to make sure the cat would function well. Long story short, I failed again - this time only on the HC at 75 PPM vs 64 PPM max - I was much closer to passing the second time. Since I have a new converter, o2 sensor and everything is functioning properly, I don't know what else to do. Please let me know if you guys have any thoughts. thanks