Making Hypermiling easier with Buttons
 

http://bp1.blogger.com/_2A3Fl4I3bzo/...0/IMG_0486.jpg
I installed a toggle switch to turn on the radio, a toggle switch to turn on the computer and fuel pump/injection, and a push button starter switch. I used a 40 amp auxillary headlight relay to reduce the current through the computer power switch, the stereo toggle is a 20A switch, and the starter button is a heavy duty one, so no relay was needed there.
Here are the switches exposed; the start button is where the cigarette lighter should be.
http://bp0.blogger.com/_2A3Fl4I3bzo/...0/IMG_0488.jpg
I had a couple of people ask how the wiring is done, and if you could do it differently, so here you go! More details are on my blog.
http://bp0.blogger.com/_2A3Fl4I3bzo/...ortWiring1.JPG

http://bp2.blogger.com/_2A3Fl4I3bzo/...ortWiring2.JPG

thats cool, but whats the point?

Cutting off electrical accessories saves fuel and killing the fuel pump/ECU during coasting will do the same.

Following Johnny Mullet's comment, you can kill the ecu and accessories while coasting with the key. With buttons, you can avoid risk of locking your steering column while rolling, reduce wear and tear on your lock cylinder and ignition switch, and eliminate the radio shutting off every time you restart your car. (most cars' ignition switches remove power from the climate control and radio/windows while starting to ensure an easy start. Killing the radio is unnecessarily annoying when it's a small one with little electrical load)

Yep i got plans for a engine kill switch mounted on the shifter for easy EOC, and may do a start button near the shifter too..

Well the starter motor already has a relay inside it.. that smaller cylindrical lump on the side.

I'm really anxious to start using mine... still getting a baseline for this car's OEM economy before I change anything about how I drive or how the car drives.
I hopefully won't have to use the start button too often; this little car is super easy to bump-start, and I just replaced the transmission mount to make sure it's ready!

Oh, I know, but I wanted to make sure anyway - I didn't use my DMM to test the current through that wire - I should have.
Another 40A relay with a 5A button was what I was going to try, but O'Reilly's discontinued the line that carried the one I wanted, so I went with the Heavy Duty version - a big brass button.

The person who had my car before me installed a push button ignition. They were trying to make the civic into a tuner, but did not get very far. I have one toggle switch for the entire electrical system and then a momentary push button for the starter.

The system works well for EOC. I get up to speed and flip the toggle switch to kill the electrical. I then turn the electrical back on to power the odometer. When it is time to start the engine, I just push the starter button.

I have no idea how the person wired it, but it seems to work well and I have seen no ill effect in the 4 months I have had the car.

I would not want to kill the ecu all the time, as modern ecu's have a learning feature, and are probably not as efficient compared to if you have been driving a whole day or two with no interruption to the ecu's memory. Turnin off the engine @ key isn't cutting all the power to the ecu. I used to do that to get rid of check engine lights when I overboosted my srt-4. I would get the WOT power back with a reset, but the car ran ugly on both the streets and the highway for a few minutes everytime. I dont know how you did your mods. However i DO have an injector cutoff that is installed, and who knows if its really making a difference I plan to make it all automatic with vacuum switches that open/close when throttle is released.