The Spark EFI project is a flexible, fully featured Engine Management Systems (EMS aka ECU) based on the low cost and open source Arduino and STM32 platform. It provides the firmware and software components that make up an engine management system, all provided under open licenses. Spark EFI boards are speeduino software compatible. This repository has speeduino software customized for SparkEFI boards.
The Speeduino firmware online manual can be found at: https://wiki.speeduino.com
Pre-made Spark EFI units/boards are available from a number of official resellers
In addition the manual referenced above, Speeduino has a large and very vibrant community of people to help out with your setup or any questions you might add.