Making Hypermiling easier with Buttons
 

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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.
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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.
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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.

True; I'm not removing all power from the ecu; just removing the main power to it. Since I wired it from the ignition switch, it's exactly the same as shutting off with the key. Just like your stereo always has a power source to save your radio stations, the ecu has additional wires to save its memory.

Nice. I'm considering at least adding an engine-kill and starter button to the xB, so I can EOC more. I found wiring diagrams, now I just need the nerve to go ahead and do it. Granted, I won't go to the extreme you went, killing power to everything, but just being able to start and stop the engine easily would be nice.

Of course, I can't find actual information from anyone who has done the same to their box, and every time it comes up on a Scion forum, the idea is greeted with derision and accusations of rice, with no actual information provided.

Hello,

The switch I want would let me turn off the A/C when the windshield defrost is on. On my Scion xA, you can't have the fan blowing air on the windshield (only) w/o the A/C being turned on...grrrrrrrr.

Ever drive in an ice storm?! (You don't need no stinkin' A/C, that's for sure!)

I had that exact head unit in my 66 Vw Deluxe Bus in high school (burnt to crisp on day before High School Graduation) Last headunit that I was ever totally satisfied with.


Sorry, nothing useful to add to this thread :-(

I've suspected that the xB has this "feature" too. I use the defroster setting as sparingly as possible, as a result, even though I've never heard of it specifically. This is common to a lot of cars. Some let you disable it by simply turning off the AC, whereas others don't let you know that it's even on.

In the Subaru I had previously, I disabled the AC-with-defrost by taking apart the HVAC controls and physically breaking the tiny switch for the AC. It worked well like that. If it wasn't 200 degrees outside, I'd explore this in the xB.

I think ill move my switch to the ecu wire, good concept i skipped over, I went for injectors only on this car.

BTW i LOVE dics on xBz, there are lots of clubs out here in socal and one by one the ones who stayed with steelies are going to space dics just like your avatar there :)

Thanks. I get a lot of people asking me about them-- they don't seem to make a difference with FE, but they look great, which is fine with me.

I can kill the engine by turning the key back about halfway to fully off which leaves all the electronics alone, but I do slip every now and then and kill everything which is more annoying than anything. Buttons would be handy, but not necessary.

My car has that "feature" with the A/C on the windshield. Supposedly it dries the air which helps eliminate the minor condensation which is the fog, but it worked fine in my Focus that had A/C optional...

Yeah, exactly. If I really need the AC on to dry the air, I am entirely capable of turning it on manually. I never missed it after I disabled it in the Subaru, and the GMC I had before that didn't even have AC in the first place. At best, it's not that necessary.