To any body with experience with retro fit old school with new school and tuning the tachometer settings on hp tuners. This is what my problem is, and what I'm doing. I'm using the original 4 pulse tachometer that ran off of the distributor on the 1978 350 corvette. I'm using a 06 GTO LS2 and 4l65e platform dropped into the old 78 corvette. When in HP tuner with the setting on crank and res 3/3 high/low (24x crank) should create a 4 pulse signal as far as I'm told, but with all that set with the pull up and 1k resistor in place the E40 will not ground it out and create the pulses. Now with the setting in HP tuner set on frequency it at least moves the tachometer and grounds, but is about (analog) 2 pulses off and keeping in mind the tachometer is calibrated. What is your thoughts on this am I missing something, or is the computer bad? I have check all connections multiple time and the plug on E40 found everything in order.