[cRiPpLe_rOoStEr]

Originally Posted by Stubby79

Obviously, if it's burning oil or running terrible and putting out unnecessary levels of exhaust/emissions from running rich or whatever, it's not doing anyone any favors.

They often point out how a new car puts out less emissions than an older car...and, of course, in some ways, no matter what you do, it will be relatively higher, but I'm of an opinion that a lot of that comes down to maintenance and how people won't (pay to) fix a $500 car. So they keep on driving it while it's blowing oil, coolant, or excessive fuel out the tail pipe. It has the potential to be much cleaner, not it's fault it's not been given that chance.

Let's consider newer engines with sequential fuel injection get an effective decrease on unburnt hydrocarbon emissions compared to carburettors and earlier EFI setups with a continuous fuel flow. Sequential fuel injection is also easier on the catalysts. On the other hand, looking at both the viability of retrofitting SFI to an older engine once it requires an overhaul and the lower footprint of keeping its bodyshell instead of looking for a brand-new car which is supposedly "cleaner" on the long run, sometimes it's better to keep a beater and eventually performing some upgrades instead of going into the new car market for a debt that would be greater than the environmental claims. And even some engines with an ancient design may still be suitable to upgrades which will keep them up to the current emission regulations at a lower expense, considering port-injection won't require particle filters which are becoming more common even on gasoline engines due to the widespread of direct injection.