Had a buddy of mine ask me this at work and really didn't know how to tackle the answer so I figured I'd ask the good folks here for some insite.

Would downsizing the injectors (from 48lb/hr ones to 30lb/hr etc.) or decreasing the fuel pressure at the regulator help with his chances of passing smog?

 

I don't see how that would change anything unless the PCM is not tuned for the larger injectors.

-Dustin-

 

If its tuned for the larger injectors then no. One trick I hear of people doing is driving the car to smog with nothing but 1 gallon of denatured alcohol in the tank; I would never do it on my car though.

 

What are the numbers that he got on the last smog test. Different numbers need different responses.

Changing the injectors like suggested will make the engine run very lean which will drop the HC numbers but increase the NOx numbers. No one can tell you what's going to happen without more data...

 

This is about the responce I figured but I couldn't be sure. I just thought it was a wierd question, didn't really ask him for more detail...