EFI guys, any options for theft protection?

DionR said
That's exactly what I am talking about.

Can you do more than one table? Or is it one of 2 tables?

My first thought would be 3 separate tables. One standard one, one valet table with the rev limiter down to 1500 RPM and a no-start table with zero fueling. A lock signal uses the no-start table and a missing fob uses the valet one. So when you lock the doors, car won't start. If you toss the key to a valet (assuming the car doesn't have pushbutton starting) he/she could start the car but the missing fob would limit it to 1500 RPM.

Another option might be a full power table (red key) and reduced power (black key) for wife/kid/etc. But instead of a different fob, just use no fob at all and limit the RPM and/or reduce timing.

I have seen keyless entry and pushbutton start systems that use RFID tech. Not sure if it could be used though.

Cool stuff. The fact that MS can do table switching based on an input is enough. More than 2 tables would just be extra frosting on an already sweet cake.

Hmm, I know there are actually 4 tables in the computer, but I believe the switch function is limited to just 2. The other 2 are meant as blend tables for something like E85. So you really only have 2 main tables, but each table has a matching blend table that it would interpolate between depending on the percentage of E85 a flex fuel sensor would detect. I guess maybe you could kind of trick that with a switch though. If it just blends tables based off of some analog input (probably a 0-5V sensor kind of deal), you could just set up a switch to send either 0V or 5V, so it would effectively "blend" fully to one table or the other.

However, you might be able to get clever as the fuel and ignition tables can be on independent switches I believe, and each of those has the 2+2 table setup. So in a way you might be able to get close to what you are looking for. The valet mode could swap the ignition table between normal and heavily reduced timing for reduced power and the fuel table could switch between "start" and "no start" effectively.