[Piwoslaw]

Originally Posted by Diesel_Dave

I'm more familiar with larger diesel engines, but I've never, ever seen any data showing a fuel economy benefit from EGR in a diesel

I don't remember where I read it (maybe here?), but in a diesel increasing EGR only works up to a certain point - first it reduces NOx without compromising performance, but then everything starts to fall apart.

Originally Posted by Diesel_Dave

(with all the same engine settings otherwise)

Exactly!

Originally Posted by Diesel_Dave

I know for diesel trucks there are a lot of sims, chips, & programers to remove EGR in such a way that the other engine settings are negatively affected. There are probably similar things out there for the TCI engine. You might want to look into them, but be forewarned that there's a lot of crap out there too.

I believe this is what the OP is attempting to do: cut EGR while emulating sensor readings for the ECU's sake to make it think everything is OK. I wonder what the effect will be? Since the ECU will think that the intake air is partially emissions, the fuel dosage/timing will be changed accordingly, compared to an intake charge of clean air.