California Smog Test

I'm having a severe problem getting my 1987 Nissan to pass the California Smog Test. For the second time in a row, I was required to go to a "Test Only" station. These stations are not allowed to perform any repairs and therefore when I failed, I had to take my car to another mechanic. The car is one of the last carbureted models manufactured by Nissan.

This mechanic worked on the car and made some adjustments to the timing. He also replaced the EGR valve. Unfortunately, although he is a licensed California Smog Mechanic, he couldn't sign me off for the smog test as I had to go back to the "Test Only" station.

The car passed the HC and CO tests easily but failed the NO tests by a significant margin. Assuming that the EGR valve was properly replaced and is working correctly now, is this condition something that replacing the catalytic converter might solve?

I'm having a severe problem getting my 1987 Nissan to pass the California Smog Test. For the second time in a row, I was required to go to a "Test Only" station. These stations are not allowed to perform any repairs and therefore when I failed, I had to take my car to another mechanic. The car is one of the last carbureted models manufactured by Nissan.

This mechanic worked on the car and made some adjustments to the timing. He also replaced the EGR valve. Unfortunately, although he is a licensed California Smog Mechanic, he couldn't sign me off for the smog test as I had to go back to the "Test Only" station.

The car passed the HC and CO tests easily but failed the NO tests by a significant margin. Assuming that the EGR valve was properly replaced and is working correctly now, is this condition something that replacing the catalytic converter might solve?

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Thanks in advance for any suggestions.

Gerry

Thanks in advance for any suggestions.

Gerry