DIY: Honda FIT Kill Switch

[Veen]

Originally Posted by marky899

Would it not be a good idea to just connect into the actual key switch wiring so when the Normally open witch is closed, it replicated turning the key to off mod and when released, it replicated turning it back on.

I may be looking into the key switch circuit for my car if the injector circuit doesn't work out. My biggest concern with key off is all the other systems it may kill. I doubt electronic key off would lock up the steering column but you can bet I'd test it thoroughly before hitting the road.

Originally Posted by Baltothewolf

Veen, I would recommend not continuing to kill your car with that method. Your vehicle is doing what is called 'dieseling' in essence, your car is spraying fuel and detonating it without spark. Very unhealthy. Go the injector method, it's tried and true.

Thanks for the head up Balto. With the extra toggle switch, it was easy to disable my kill switch so I didn't use it out of habit. Now I just need to figure out an injector or key off kill... and look into a cleaner product for the engine. I'm sure I added a little carbon build-up with the dieseling

[California98Civic]

Is there something so much different about a 2009 Fit's wiring compared to a 1996-2000 Civic that means you can't just cut the ground to the fuel injector relay? I did that five years ago on my 1998 Civic. The worst thing that has ever happened has been a switch failure after tens of thousands of uses. All the switch failure required for repair was reconnecting the ground wire with a buttsplice in the car and driving home using key off for engine off coasting. Took less than 5 mins to repair, and failure only happened because of my novice design flaws. Wire failed once. Switch failed once. I moved the wires so they would get less stress from the shifter knob's movements, and later I got a more robust switch. No new issues.

[Veen]

I'm not sure. I haven't really had a chance to study the FIT wiring. I really need to pick up a Haynes manual for the car. I am leaning towards cutting the injector circuit. Do you know how much current generally flows through that circuit?

[California98Civic]

Originally Posted by Veen

I'm not sure. I haven't really had a chance to study the FIT wiring. I really need to pick up a Haynes manual for the car. I am leaning towards cutting the injector circuit. Do you know how much current generally flows through that circuit?

I am not sure, but if you cut only the ground, that concern is less significant, which is why I chose to do it that way. Try only reversible tests at first. Often the wiring diagrams mislead a little, and we only discover that more components are affected after we have cut a wire. It can be easily repaired, but the wiring aystem in permanently marked, of course.

[marky899]

Im planning on doing this EOC mod within this next week. Just waiting for parts to arrive.

Im planning on dirupting the Crankcase sensor signal to cut the engine as it seems to be the simplest and best way for me to achieve what i want.

I have a question regarding wiring though. Im wanting to add a toggle switch inline with the momentary closed switch, so that when the toggle switch is in the off position the momentary switch will not be able to interupt the sensor singal. Im not 100% sure how to go about doing this because if its in line with the momantary switch and the toggle switch is off, then the signal will also be interupted this way, and thats not what i want. I want to be able to just make the momentary switch active or deactive.

thanks

[Veen]

Originally Posted by marky899

I have a question regarding wiring though. Im wanting to add a toggle switch inline with the momentary closed switch, so that when the toggle switch is in the off position the momentary switch will not be able to interupt the sensor singal. Im not 100% sure how to go about doing this because if its in line with the momantary switch and the toggle switch is off, then the signal will also be interupted this way, and thats not what i want. I want to be able to just make the momentary switch active or deactive.

Because you are interrupting the signal directly with the momentary switch, it will be difficult to also add a toggle switch. The only method I can think of is to add a relay.

Use a relay to interrupt your crankcase signal. The toggle switch and momentary switch in series would be used to apply power to the control (coil) side of the relay. You could do the same thing with a FET or transistor but a relay is probably simpler.

[California98Civic]

Originally Posted by marky899

Im planning on doing this EOC mod within this next week. Just waiting for parts to arrive.

Im planning on dirupting the Crankcase sensor signal to cut the engine as it seems to be the simplest and best way for me to achieve what i want.

I have a question regarding wiring though. Im wanting to add a toggle switch inline with the momentary closed switch, so that when the toggle switch is in the off position the momentary switch will not be able to interupt the sensor singal. Im not 100% sure how to go about doing this because if its in line with the momantary switch and the toggle switch is off, then the signal will also be interupted this way, and thats not what i want. I want to be able to just make the momentary switch active or deactive.

thanks

It might be simplest, but consider that the car's OEM switch probably cuts fueling at the injectors and the pump as the primary difference between "run" and "on." If you cut just the crank case signal, the car will probably run-on a little until it cuts fuel. Doesn't that mean fuel getting pumped into an engine not running very well anymore? Won't that mean possibly fouled plugs, and maybe a pligged CAT? Better to stop the injectors on a dime, by cutting their power, no?

[marky899]

Originally Posted by Veen

Because you are interrupting the signal directly with the momentary switch, it will be difficult to also add a toggle switch. The only method I can think of is to add a relay.

Use a relay to interrupt your crankcase signal. The toggle switch and momentary switch in series would be used to apply power to the control (coil) side of the relay. You could do the same thing with a FET or transistor but a relay is probably simpler.

I actually bought a 5 pin relay and a momentary off/on switch as i was originally going to do this mod via the injector fuse. I dont suppose you would be able to give me some advice on how i would have to wire the relay and everything in to do what you have suggested? I dont really have any idea where id start with relays.

Originally Posted by California98Civic

It might be simplest, but consider that the car's OEM switch probably cuts fueling at the injectors and the pump as the primary difference between "run" and "on." If you cut just the crank case signal, the car will probably run-on a little until it cuts fuel. Doesn't that mean fuel getting pumped into an engine not running very well anymore? Won't that mean possibly fouled plugs, and maybe a pligged CAT? Better to stop the injectors on a dime, by cutting their power, no?

Thanks for that suggestion. as mentioned above, i was originally going to kill the injectors by using a relay to disrupt the signal going to the injector fuse. But i have no idea where the injector fuse is on my car and from reading posts By 'bdc' in this thread http://ecomodder.com/forum/showthrea...-how-4356.html it convinced me to just go the route of the crankcase signal. According to bdc the ecu should cut the ignotion and injectors as soon as it senses a loss of signal from the crankcase to stop it causing damage.


Any other suggestions or advice is much appreciated though.

thanks

[marky899]

hey guys, so regarding my cam sensor.

it only has 2 wires. ive been told that one will be an earth wire and the other will be a signal/power wire.

Am i still able to plug EOC switch into this? Does it matter which wire i disrupt. Ground or live?

Cheers

[California98Civic]

It won't matter much. But I would choose the ground wire. You can test by disconnecting each wire and see if there is any difference in how the car shuts down.