So you want to learn more about EFI theory, ECUs, or just stuff in general. This is intended to be a place to put links to stuff worth reading. Hon Data's website - tons of good information, much of it very aplicable considering they use stock ECUs as the base for their standalone http://web.archive.org/web/20250925104144/http://web.archive.org/web/20250925104144/http://www.diy-efi.org// - started out with a heavy slant towards domestics but has a WEALTH of good knowledge and tons of very smart individuals on the mailing list http://web.archive.org/web/20110910002838/http://web.archive.org/web/20110910002838/http://www.efi-tuning.org// - a site dedicated to tuning mostly GM and Bosch (BMW,etc.) ECUs http://www.eci-multi.org - PGMFI's equivalent for DSMs. http://www.sdsefi.com - a commercial vendor of standalone engine management systems that has a tech section with every article worth reading twice http://www.howstuffworks.com - a great site with many quality articles on automotive related topics, as well as a ton of information on the scientific theory behind the operation of things. Tons of pictures, fascinating redaing. http://www.bgsoflex.com/megasquirt.html - The Mega Squirt is a homebrew DIY fuel injection computer that is pretty well documented and has full schematic. http://www.bgsoflex.com/mjl/mjl_edis.html - Mega Jolt is a prtially complete system for controlling ford EDIS modules https://www.msextra.com - Mega Spark is a DIY system for controlling spark standalone using a 6AL or similar to drive the spark itself.