Im trying to figure out how to make a circuit that takes an negative injector pulse (0-16ms from a car engine) and converts it to a 0 to +7v signal for the vehicle consumption indicator to monitor. It would have to be adjustable because the injectors will be 3 times the size of the stock injectors. It would have to have very high impedance to not screw up the injectors pulse. Injectors are normally between 1 and 16 ohms.

I will be logging the injector pulse and 0-7v signal with an oscilloscope to get the calibration soon. It should be a straight line. The older cars used an airflow plate with a 4khm: position sensor (part of the mechanical fuel injection) to give the 0-7v signal to the consumption indicator with this curve.



I believe the curve should actually be linear to the injector pulse because the airflow plate looks like this ( The voltage curve almost fits the contour of the "bowl")



The airflow past the plate has to be linear to supply the correct amount of fuel to the incoming air.

This circuit is built into the stock computer. Problem is i am installing a standalone fuel and ignition computer so i can tune the car. Losing this functionality sounds dumb but is a helpful thing to have.

I was thinking of using a CD4066 chip but im not very good with circuit design yet.

Anyone have any ideas how to do this?