I'm not using a TSX ECU, I went with an early RSX ECU because it was most compatible with the Insight body wiring, and was drive-by-cable. The RSX ECU has no EGR output, unfortunately. I might be able to repurpose another output, but it depends on how it's controlled. PWM? 0-5v? Probably not just on/off.
Manual control might be fine. Maybe leave the valve open or at a fixed duty cycle below, say, 750mbar - that would be very easy to program.
At 0 degrees advance it appears the valves close slightly early - fueling values are lower than at 10 degrees advance. 10 degrees gives the highest fueling values at low MAP, suggesting it's the crossover point where the valves are opening late enough to get the most air in with minimal exhaust dilution. Hondata suggests to use around 30 degrees advance at low load on these engines to get some hot EGR effect. At 40 degrees the engine starts to stumble at low load operation, and fueling falls dramatically - MAP is definitely higher, but combustion quality seems to suffer.
I put a physical stop in to prevent more than 40 degrees advance, as I believe around 45-50 the high speed cam profile can cause valve/piston collision, and it seems with this intake/cam combo, having more than 40 degrees of advance doesn't provide any more WOT power.
0 degrees: -3.9% fuel
10 degrees: peak fuel
20 degrees: -2.2% fuel
30 degrees: -14.2% fuel
40 degrees: -30% fuel
I haven't had my car on a dyno yet. With my crude record keeping of fuel economy back and forth on my commute, I have not noticed any significant fuel economy difference between 10 degrees and 30 degrees advance, and perceived a slight reduction with 0 cam advance (early valve closing). I do notice that 30 degrees advance has significantly more exhaust noise (or maybe I'm hearing it from the intake?) than 10 degrees, so I've been driving around with 10 degrees intake cam advance.