OBD2-USB interface for tuning the car?
 

Hey folks. I've been looking into this MPGuino thing and scangauge, and I'm wondering something. Can you use a PC to OBD interface to adjust the settings of your ECU? Tell it to run lean and all that? Obviously you'd only want to make small changes to the existing settings, otherwise you could screw things up like crazy!

Is this possible?

You really have to know what you are doing to accomplish this, but it can be done. I knew this guy who could reprogram your PCM and other modules to do what you want it to do and disable certain features like autolocks, DRL's, seatbelt chimes, etc.

I have been trying to find him for a few months now and nobody knows where he is working. I would love to see how he could tweak my PCM.

there are projects with certain cars to accomplish this. Subaru's have a large following at openecu.org for doing this, although there has been speculation that these guys stole most of their work from other companies that sell subaru tuning software/hardware.

Like said previously, you need to know what you're doing. Each ECU has completely different software so there is no single place for ignition timing/fuel trim etc. in every ECU.