# DFCO and exhaust gasses



## NBrehm (Jun 27, 2011)

Theoretically yes, it cuts of the fuel. No fuel, no combustion, no combustion no emissions. It won't help you on an emissions test though, the car has to be moving. Even if it is a dyno type test they test under load.


----------



## obermd (Mar 3, 2012)

Thanks - Denver uses road side emissions tests and if you pass three times in the six months prior to one month before a required emissions test you don't have to go to the dyno.


----------



## NBrehm (Jun 27, 2011)

Just out of curiosity why are you worried about it?


----------



## obermd (Mar 3, 2012)

I'm not. I was just curious. I've only had to take one car in for a dyno emissions test since the road side testing started in the early 2000s. That was my wife's car and she never drives past the road side testing trucks. One of the reasons I started tracking my fuel economy back in 1985 when I got my first car to to detect engine combustion issues. These will also show up as reduced fuel economy. I guess I've been hyper-miling for quite some time. This is how I know I have always beaten the "combined EPA" estimates and almost always beat the "highway EPA" estimates.


----------

