On my 2014 accord sport of which has now 6k miles, I drive a lot of times with Econ mode turned on unless I'm feeling like hot rodding it a little. I notice that it seems like I always have that foul smell from the catalytic converter when I get on it hard with Econ mode off. Is it normal for a lot of buildup from driving with Econ mode on or is it my car is still new and still breaking it in. Any insight would be great, anyone else have the same thing? Thanks

 

Carbon has nothing to do with it, when you go Wide Open Throttle (WOT), the engine computer switches into "Open Loop" and typically enriches the mixture to "full rich" (which is what you smell when following a car with a marginally small engine struggling to get up a long hill). Just a trait of the beast.

 

Ahh so it's just a strong mix of gas and air making that God awful smell lol, thanks

 

Gas doesn't smell as good as it did in the old days!

Not a good idea to smell gas. When I was a kid I'd clean my bicycle chain with gasoline! In the house.

 

It doesn't seem to me that you should smell anything. I have a '14 Accord Sport with 17K miles on it and have never noticed any kind of exhaust odor and I have driven it pretty hard in all kinds of conditions. If it were mine I would take it in and let the dealer check it out. Also make sure you are using good quality, top tier, gasoline.

I drive with ECON turned on all the time and I don't think it matters as far as fuel air mixture is concerned. The only thing that changes with ECON is the throttle mapping, both modes (ECON on or off) provide exactly the same amount of power at full throttle but with ECON the throttle will be more linear between idle and full power instead of providing most of the power during the first part of the pedal movement. The ECON does make some other changes such as the way the climate control operates. I have been told ECON also changes the way the CVT operates but I can't confirm that because I have a 6MT.