Thanks. The analogread is all I have for pressure, I was going to assume linearity. Non-linearity is not a problem I had anticipated!
I also agree that the cylinder pressure should not significantly affect injection, I'm not going to worry about 10% effects.
My enclosure should arrive today
I have read that the "pilot injection" is a few us long, I could not separate it from the main injection last time I scoped it. So for my purposes I hope I can treat the injection as a single event. I'm thinking that running a scope whilst driving would be illuminating at this stage.
Redline is about 4500rpm; but I rarely exceed 2200 as peak torque is 184ft-lb at 1750rpm. Nice and relaxed!