I know this topic has been covered more than once. I even got some of my info for this from a thread started by Darcane. So thanks for that! I just thought I might share the process and results from my finish installed EOC kill switch.
Aside from wearing out the ignition cylinder one of the main issues with keying on and off to kill the engine is the trip meter shutting off momentarily, sometimes for 3 or 4 seconds. My guesstimate is that there is about a mile or 2 unaccounted for by the time i get to the pump. Therefore a kill switch is super handy.
I don't have factory wiring diagrams for my civic so without some help and research from others here this part would've been a little trickier. I originally planned to simply intercept the ground wire for the fuel injection relay. My thought was in doing so I instantly cut fuel to the engine, get a clean shut down and keep the ECM powered so not only is the car ready to restart right away but my trip meter continues to run during the period when I'm engine out. Turns out this wasn't going to work. The main Fuel Injection relay in the 7th gen civic feeds a second relay as well as powers the immobilizer in addition to the fuel injectors and a whole host of other sensors. In short what this means is if i cut the ground to the first relay I would kill power to the immobilizer causing me to potentially have to key off and on to reset. So the trick was to intercept the injector circuit after the immobilizer so as not to upset it.
As it turns out this yellow and black wire was the one I wanted.
That wire is found on a grey 20 pin connector behind the glove box and directly in front of the ECM
I simply cut and spliced a couple new wires into place and ran them to an on/off switch on the driver's side, being careful to route them safely so as to avoid any sharp pieces of metal. These are hot wires after all. Now I'm not a fan of hacking into and modifying original harnesses. I see butchered messes entirely too often. I tend to avoid modifying a good harness whenever possible, but when i do connections are *always* soldered and heat shrunk to be as clean, safe and reliable as possible. It's a little extra work, but anything worth doing is worth doing right. I also used wire a couple gauges larger to run to the switch, I had some similar gauge wire in the shop from other wiring harnesses I've disassembled, but it was just as easy to bump it up a gauge than to accidentally run something too small. Better safe than sorry right?
For the same reason I dislike hacking into original harnesses I also don't appreciate irreparable damage to interior panels and dashes. I found a good attaching point on the throttle pedal side near the obd 2 connector to mount a simple L bracket. Some quick drilling and painting and the bracket was ready to bolt in.
The switch is a simple LED on/off, i ordered 10 off ebay for .99 shipped from china. (Honestly have no idea how they do it) Key on and if the switch is on I get a blue indicator light come on with the rest of the dash lights, telling me the system is hot and ready to start.
Flip the switch off, kill the engine and the indicator goes out.
Having used it all day I can say the functionality is seamless, works just as intended with no CEL after the next startup and no immobilizer problems. It's really pretty awesome to have an alternative to keying on and off continually. Thanks for reading along and let me know what you think!
