flex fuel

What do I have to do to my 93, 3.1 liter lumina, to make it flex fuel, do I just get a new computer and put in a sensor or is it much more complicated than that.

flex fuel? I'm not familiar, please ellaborate. Do you mean e85?

Flex fuel cars can run on a wide ratio of ethanol blends or straight gas, or any combination your tank might end up with, a sensor determines the octane level of the blend and changes feedback parameters accordingly to control timing, knock, etc.

Their fuel system is completely different, as far as I know. Everything has to be able to withstand the degradation that ethanol can cause, from o-rings to injector pintles. I don't know for sure, but I can't think of any reason why you'd want to go to that system, unless you have a line on a supply that's cheaper than gas.

The few things I've read about GM flex fuel cars made them sound like they have maintenance problems.

This should give you an idea of what would be necessary to run E85, which in turn means that this kind of work is the least that would be required to run the various fuels.

http://www.westbioenergy.org/reports/55019/55019_final.htm

Its a GM 60°V6 vehicle, and you can read all about E85's corrosion factor on a stock gasoline system. Pretty interesting stuff, I thought.

Well I know that chevy made some 93 luminas flex fuel, so my brother said that thay might all be compatible with alcohol they just need some sensors, and a computer. I can get e-85 much cheaper that gas so it would be worth is if I could make it flex fuel.

I'd think that if you had a E85-compatible car, you'd already have the entire system. I don't think GM would partial something like that, due to costs to outfit a regular gasoline vehicle with E85-compatible components being too much. If your entire fuel system can withstand E85, I would assume that yes, all you'd need is the ECM and the octane sensor w/wiring. But again, I think if you need to add the computer and sensor you probably don't have the rest of the components (different materials in the lines/injectors/etc).

I don't doubt that E85 is cheaper. When I was in MN in August, E85 was $1.75 and regular was already hitting $2.25. It'd be nice and while the long-term costs might offset the work required, you're in for a LOT of work and money in the short term.