Is there a simpler version of MegaSquirt® to only control extra injectors piggyback style?
A. You can use the standard MegaSquirt® EFI Controller to control extra injectors. • You wouldn’t need to hook up the coolant temperature sensor, if you didn’t want to, you would just set all the temperature dependent values to 100% (warm-up enrichments, cold accel enrich., etc.). • You don’t need to hook up a TPS, you can just set all the accel enrichments to 0, and hook a resistor from the input pin (#22) to ground (otherwise the CPU will see a climbing value and go to ‘flood clear mode’.) • You don’t need to hook up an oxygen sensor, just set the EGO step size to 0%. • For the air temperature sensor, you would just hook a resistor across the pin (#20) where the sensor would normally connect. This resistor could have any value from the sensor curve (in the sensor section of the manual) to approximate whatever temperature you think appropriate, or you could use a potentiometer to tune the extra fuel with a single knob. There aren’t substantial differences in between tuning a piggyback
