Ignition kill switch
 

I need to figure out the best method for killing ignition power to the engine from a momentary switch. I'm looking to set this up to so I can coast with my engine off frequently. Do the coils or injectors share a common 12v source, or ground? Specifically, i need something that keeps my dash and odometer powered.

Re: Ignition kill switch
 

I deleted the double post.

What's the purpose of killing the engine? You'll lose your power steering doing this as well.

Re: Ignition kill switch
 

sorry for the double post. the purpose is to conserve fuel. its a pretty common tactic, in my case its just a matter of figuring out the right place to to install it. right now i do this with the key.

Re: Ignition kill switch
 

Did you know if your coasting with your foot off the gas the Civic will automatically cut the fuel off? I think over 2500 rpm. Sdaidoji knows more about this than I do, perhaps he'll chime in eventually.

Re: Ignition kill switch
 

Right now I am coasting in neutral with the engine off or sometimes on depending on how soon I will have to stop. I am coasting in gear only if i need to stop sooner and want to use some engine braking. I am virtually never at more than 2500 rpm at anytime driving the car. the exception is cruising at 65 which is about 2600 rpm. I usually shift before 2500 rpm.

i did find the answer to my question though on another forum. The injectors share a common 12v and a relay can be wired in there. This thread contained the details.

Re: Ignition kill switch
 

if you are turning the engine off with the key, i warn you that if it goes slightly too far, and you need to suddenly swerve the steering wheel will lock! Don't do it!

yes, it will cut off in gear, downhill, at 2500 RPM. Below that i do put in neutral. more than enough to get me these:

Attachment 90636

three times last week.

Re: Ignition kill switch
 

umm..wow.

how much of a difference does that make for mpg?

Re: Ignition kill switch
 

My usual is 32 to 35, but since temps are lower, no AC, and the traffic have not been bad, so 60-70 mpg on my morning commute = 39 mpg. Of course, lifting throttle or neutral when I can - driving is 90 % of all fuel economy :)

Ah, I don't brake in 96% of the corners, car can take them easily at posted limits :)

Small engine means momentum cars. Just keep it rolling and they delivers :) actually, this also helps driving fast :)

Stock 99,

Getting a scangauge or similar helps finding the best for mileage.

If I am entering a hwy, for example, I step in the gas - better reach steady state speed and keep it. Uses less gas than taking two days to reach posted limit (in small engines cars).

Re: Ignition kill switch
 

No... I mean how much mpg difference does the kill switch make?

Re: Ignition kill switch
 

As others have mentioned this is dangerous while driving

-no power steering (at speed this isn't that much of an issue
-no power brakes!!! this one is scary (happened to me when my alternator died, had to slam on the foot brake, which was super stiff and hardly did anything and pull the drift handle, to avoid rear ending another car while my engine cut on a steep downhill).
-steering wheel can lock

I can do this though because when I swapped my car to manual I grounded out the brake and clutch position sensors as well as the auto shifter... my car always thinks it's in park, since I left in the auto gauge cluster, lol. On the plus side I can start and Idle my car without stepping on the clutch or brake... on the down side since I leave my car in 1st while parking, if someone didn't know how to drive stick and went to start my car without stepping on the clutch it would lunge forward (most manuals won't start without the clutch depressed).

Ignition kill switch
 

I have yet to run out of vacuum on the brakes when coasting. This includes several times using the brakes. There is still a vacuum reserve when the engine is shut off. As for the wheel lock, A, that doesn't happen when you use a kill switch. And B, even with the key, you shouldn't be turning the key far enough to engage the wheel lock, and they you should the key right back to ignition once it's off. The technique is not for everyone, but I don't consider it very dangerous if you use common sense.

Re: Ignition kill switch
 

my brother thought he had only killed the engine. well, he simply went a tad too far. pretty expensive suspension damage, for the little savings he got...
i won't recommend...

no need to go that far... that could end up involving other people that does not have anything with your choice of doing it. See, i did it this morning again. it's plenty possible without doing engine kill. some less bright guy might read this and think it's OK... (that's the reason I can't agree, even if you can do it safely... Yeah, the kill switch will keep the wheel unlocked, so that's better than using the key.)

Attachment 90629

PS: Not cell phone, just a camera that can quickly turn on an shoot pics.