Kill switch questions

[r3tic]

I have a 1999 civic lx and I am wondering the best method of installing a kill switch. I'd prefer to not kill the gas pump as seen on another thread in this forum because it is not an instant kill. I'm open to suggestions.


Thanks

[suspendedhatch]

It's not an instant kill because there is residual fuel pressure in the lines. When you shut off your car normally, this residual pressure remains for several hours until it feeds back into the charcoal canister.

You could kill the ignition but it's a higher amperage circuit so a relay is required. It would be identical to an alarm's start kill relay, the only difference is that you're putting it on the ignition wire and using a manual switch to control the relay instead of a ground output from the alarm.

[theholycow]

I'd like to hear this too...I want to install one in my 2008 VW Rabbit.

[DRW]

Kill the injectors.
I don't know how it is on your car, but my car uses a common ground for all 4 injectors. One wire, one switch. The injectors only see 12 volts and low amps, so no relay is needed. Just make sure you wire up the switch with male/female plugs located in a convenient spot just in case the switch fails you can plug the injectors back in.

[theholycow]

I would definitely use a nice connector, since I want it to be easy to return to stock. Good idea on the common ground, both my vehicles use a common ground on all injectors.

Would killing the injectors throw a code?

[GasSavers_bobski]

Originally Posted by suspendedhatch

When you shut off your car normally, this residual pressure remains for several hours until it feeds back into the charcoal canister.

The charcoal canister stores fuel vapor from the gas tank. It has nothing to do with the fuel pump, injectors or liquid fuel lines.
Residual pressure is supposed to remain in the lines as long as possible, to help with starting... there's a check valve in place to help with that. Unfortunately, the check valves aren't perfect, and wear out with time, allowing pressure to bleed back through the fuel pump to the tank.

Originally Posted by suspendedhatch

You could kill the ignition but it's a higher amperage circuit so a relay is required.

Not really. You just need a switch that's rated properly for the power draw. I can't speak for other makes, but r3tic's Civic would throw an ignition system error code if you cut power to the distributor.

Originally Posted by theholycow

Would killing the injectors throw a code?

Again, I'm familiar with Hondas mostly, but in all likelyhood, yes.


So... What's wrong with flipping off the existing ignition switch, anyway?

[theholycow]

Originally Posted by bobski

So... What's wrong with flipping off the existing ignition switch, anyway?

It's connected to a lot more things than just the engine.

[suspendedhatch]

Good call on that first one bobski. Something didn't feel right about it when I posted it.

Cutting the ignition on a Honda doesn't throw a code but it makes your battery light and engine light come on just like you've stalled.

I recommend a relay over a high amperage switch for reliability and also so you're not spiking the circuit every time you cut the ignition. You can buy a pre-wired base for the relay that already includes the diode, or you can wire it yourself. It's cheap and easy insurance.

[r3tic]

I'd rather not use the inition switch for a couple of reasons. First of all, there is always the chance of turning the key back too far. Secondly, I have only owned two Hondas, 95 Del Sol and this Civic, but the key sits a little looser in the ignition than with my Del Sol and I'd hate to cause any additional wear and have to replace the ignition.

The injector kill seems to be the best method, is there anyway to find out if this would throw an error code without actually cutting wires? Or is there a method that would not throw a code?

[GasSavers_RoadWarrior]

Look see if you have an ASD (Auto Shut down) relay, play with that.

I've heard that on some vehicles, when they flood and won't start, pushing the gas pedal right to the floor and cranking cuts the injectors. Could find what sensor/switch inputs trigger that and fudge them.