Results are a little confusing when comparing all categories of emission.
So which pollutant would be considered worse?
Your system passed both test, with or without the EGR, as I inform my customers.
Your testing showed a slight increase in CO and HC and a decrease in NO.
So is it better for the enviornment, if that is the only goal?
Another factor to consider is if the activation of the EGR without ECM control causes the O2 to read a different mixture and then while driving, will actually cause the system to adjust the AFR, creating more polution then it would have if you didn't activate the EGR.
So the real question is, are you helping or hurting by doing what you think is helping?
Sort of like buring up an entire forest while trying save the spotted owl habitat.
Did it really help?