Screen-shots of the calibration tables/constants.
The first table is the VE compensation, where you see that the effective VE is reduced for use in the fueling calculations based on a 35% reduction due to EGR contamination.
Some of these calibration tables are misleading in that some aren't used in my application, and the fact that only part of this VE compensation table is actually used in my application due to the type of hardware operation the factory provided. My particular EGR system did not incorporate a duty-cycle (DC) type of EGR controller. Some other vehicle models did.
http://i702.photobucket.com/albums/w...EGRscreen1.jpg
In the next shot you can see how one of the fuel injector constants is adjusted for EGR-on operation in order to compensate for some of the fuel adders during transients. Most of the gains aren't used in my application since there was no way to apply them directly to the EGR flow.
http://i702.photobucket.com/albums/w...Rscreen2-1.jpg
Below you can see some of the qualifying thresholds for EGR operation. I added some of the closed-loop qualifiers as well. The EGR only functions in closed-loop.
http://i702.photobucket.com/albums/w...Rscreen3-1.jpg
Only about 80% of the EGR information is shown here. When active, EGR has a hand in a great many ECM functions via checks and compensations.
Note, there is no PE threshold compensation for EGR-on in this calibration, nor do I commonly see one. That means that the vehicle will go into PE Power-Enrichment more often when running the EGR. The lower power output produced combined with more TPS% and more MAP - manifold pressure requires that this be the case. AE - Acceleration-Enrichment is also activated more, and more often with the use of EGR.
You should try to compensate for these conditions when trying to gain MPG while using the EGR.