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glkuntz · 02-25-2015

[QUOTE=Okiedoke;220729]I changed out the O2 sensors, engine oil, and went to the smog place recommended by my mechanic with the engine hot and I passed!! I don't think the O2 sensors did anything for NOx. The 25 MPH measurement actually went up from 459 PPM to 519 PPM. The average is 223 PPM. If anyone knows why my NOx is still so high and how I could get it down, I'm really curious to know. All of the other measured numbers are all below the average.

I think what made the difference is not anything I did to the car but in the values entered for the smog test! The previous smog place put "CORVETTE" instead of "CORVETTE ZR1" as the Model. They also entered this as a "California" instead of "Federal" car in the Certification field. Entering these values correctly actually raised the NOx MAX levels from 545 PPM to 757 PPM (for 15 MPH) and from 502 PPM to 696 PPM (for 25 MPH).

I'm curious how the smog guy got away with using Federal instead of California certification. It's a Ca car is it not? The 49 state Federal standards are no doubt less strict than Ca. which is potentialil why the Max limits were higher, about what they used to be in Ca.

I sure hope you actually get your registration and that I can convince a local guy to do the same.

Gary

02-25-2015	#79
glkuntz Join Date: Jan 2011 Location: Northern Calif Posts: 16	Re: Passed! Passed! Passed! Woohoo!!! [QUOTE=Okiedoke;220729]I changed out the O2 sensors, engine oil, and went to the smog place recommended by my mechanic with the engine hot and I passed!! I don't think the O2 sensors did anything for NOx. The 25 MPH measurement actually went up from 459 PPM to 519 PPM. The average is 223 PPM. If anyone knows why my NOx is still so high and how I could get it down, I'm really curious to know. All of the other measured numbers are all below the average. I think what made the difference is not anything I did to the car but in the values entered for the smog test! The previous smog place put "CORVETTE" instead of "CORVETTE ZR1" as the Model. They also entered this as a "California" instead of "Federal" car in the Certification field. Entering these values correctly actually raised the NOx MAX levels from 545 PPM to 757 PPM (for 15 MPH) and from 502 PPM to 696 PPM (for 25 MPH). I'm curious how the smog guy got away with using Federal instead of California certification. It's a Ca car is it not? The 49 state Federal standards are no doubt less strict than Ca. which is potentialil why the Max limits were higher, about what they used to be in Ca. I sure hope you actually get your registration and that I can convince a local guy to do the same. Gary Last edited by glkuntz; 02-26-2015 at 01:18 AM.