Ok, 50k ohms it is, for rx and r2. I did some bench testing. With a 16.2v supply the pin went high at about 14.9v. That should translate to any injector signal that is 1.3 volts or more below system voltage registering as "injector open".
With 50k on two of the transistor leads, it will be pretty well isolated and should prove reliable.
It will also allow the strongest signal for the saturated injectors (the majority of vehicles have saturated as far as I can tell), whereas the resistor patch attenuates the signal for saturated injectors.
And it seems to be operating within established parameters.
So I like this solution now
Coyote, I'll ship this guy to you so you can play with it. You are short a guino so this works out pretty nicely
