Very interesting that GM found ASDF to produce cleaner emissions in the S10. In some masks ASDF is a function of IPW to prevent commanded on times less than injector is capable of and is implemented without 1X signal. In these cases ASDF is not implemented during most operating conditions. It's noteworthy that GM resorted to hardware solution in 7427. I'd love to have more time to investigate the hardware relationship between the 1X input pin, memcal configuration, and limp mode fueling.

The list of unused pins has been pretty consistent in all of the models I've looked at. A11,A13, B6,B7, B11, B14, E7, F4,F5. Checking multpile vehicles to see if this list can be shortened might be a worthwhile approach.