1992 Toyota Corolla Q&A

1992 Toyota Corolla Question: It will not pass the california smog test plus there is no check engine light on

I want to fix it myself -
Answer 1
What is the reason for the failure of the smog check? -
Answer 2
what are the numbers?? O2 CO2 CO HC NOx, I need to know the numbers at both 15 & 25MPH. also, are there any mechanical/compnent failures indicated on yoi VIR. -