Went ahead and tried the op amp circuit. I used a pair of 47k resistors instead of the variable pot. This should give me a 2.5V drop for the injector. From the tests in my driveway this seems to be about right.
I will drive it around a few days and hook the laptop back up to the ALDL to verify that the numbers track evenly. I can brake torque it in my driveway and the numbers are dead stable. I can go up to the point the back wheels start spinning and the gallons per hour seems about right with the amount of throttle I am giving it.
I will try it out in my metro tomorrow to make sure the circuit still works with every type of injector but so far so good
