Kill switch how-to

[lightblaze]

Originally Posted by Clev

Oh, excellent idea! Does doing this trigger the Check Engine light?

Based on the thread, I decided to wire my relay switch to the cam sensor. I have a '97 Geo Metro. It was quite easy actually. I thought it was so easy I must doing something wrong. Here's what I did.

I found the cam sensor wires by locating them at base of the distributor box. Mine had a white and black (if I remember right). I carefully removed the black protective casing and spliced the white wire carefully and tied the two open ends to two 18 gauge wires that I simply connected to a 12v, 20 amp black rocket (?) switch (less than $5) on my dash. It works fine and I haven't yet seen the check engine light come on. I used wire connectors and black electrical tape.

[cassey37]

I drive an automatic and I noticed today that DFCO doesn't kick in unless I am going 45+ mph. Thinking about that, on an automatic, the torque converter has to be locked or the engine will die. Keep the safety in mind with any mods - would hate to loose power steering/brakes at "just the wrong time".

[steffen707]

Originally Posted by dcb

That's a nice writeup bbjsw10,

I had an injector kill switch on a metro, problem was it wouldn't shut off cleanly. I switched to the camshaft pickup trick (disables ignition) and it is a much cleaner transition to off and restarting, and maybe I can reuse that fuel on relight . You could kill both too with the right combination of relays, that would be more like what happens when the key is turned off.

If the ignition switch is left alone and while driving you just cut spark to the spark plugs, will the injectors keep firing and dump fuel into the intake?

If they do, that can become really bad for the oil and gas mileage. lol

[lsemple]

OK I am doing the engine kill switch, I don't think I will use the clutch pedal to kill the engine as sometimes when I come to a stop I need the clutch pedal...


So i've decided to mount a switch on my shifter knob.

Now, for killing the engine, I was going to use the injection system, but since I have a fuel vaporizer system on my PCV system, the engine will still be getting a fuel source and possibly running. So, I would like to use the camshaft position sensor. The Fuel pump sounds like it might give a delay to my kill / restarting operation.


my Car is 1993 Honda Civic Si, and I've only found a Crank position sensor which is inside of the distributor, according to autozone, and the USDM.



I am not sure if this would do the same thing,. I don't want to damage the engine. Is it ok to open this circuit ?? And, should I Momentarily open this circuit using a Momentary switch (and a relay), or do I need to keep it open using a non-momentary switch ?


Thanks I will be waiting for some answers.

[steffen707]

Originally Posted by lsemple

OK I am doing the engine kill switch, I don't think I will use the clutch pedal to kill the engine as sometimes when I come to a stop I need the clutch pedal...


So i've decided to mount a switch on my shifter knob.

Now, for killing the engine, I was going to use the injection system, but since I have a fuel vaporizer system on my PCV system, the engine will still be getting a fuel source and possibly running. So, I would like to use the camshaft position sensor. The Fuel pump sounds like it might give a delay to my kill / restarting operation.


my Car is 1993 Honda Civic Si, and I've only found a Crank position sensor which is inside of the distributor, according to autozone, and the USDM.



I am not sure if this would do the same thing,. I don't want to damage the engine. Is it ok to open this circuit ?? And, should I Momentarily open this circuit using a Momentary switch (and a relay), or do I need to keep it open using a non-momentary switch ?


Thanks I will be waiting for some answers.

I'm fairly certain your car being a 93 civic won't get fuel if you inturrupt the black ground wire that supplies the main relay. That stops the fuel pump and the fuel injectors from getting a signal from the ecu to fire. I did this same setup on my 92 civic, should be the same.

[lsemple]

Originally Posted by steffen707

I'm fairly certain your car being a 93 civic won't get fuel if you inturrupt the black ground wire that supplies the main relay. That stops the fuel pump and the fuel injectors from getting a signal from the ecu to fire. I did this same setup on my 92 civic, should be the same.

Right, but my main problem with this is that I have a fuel vaporizer which delivers fuel vapors into my PCV hose. So, the engine will still be getting fuel.
(now that I think about it I wonder if I could run only on fumes. might burn out the engine though),


anyways, this is why I need to use a different wire, like the crank position sensor.


I would love to be able to mimic exactly the electrical circumstances that take place when I turn the key back a notch to the ACC position, then back to the run position. This way the car will be ready to fire back up when I release the clutch pedal in 5th gear !

[steffen707]

Originally Posted by lsemple

Right, but my main problem with this is that I have a fuel vaporizer which delivers fuel vapors into my PCV hose. So, the engine will still be getting fuel.
(now that I think about it I wonder if I could run only on fumes. might burn out the engine though),


anyways, this is why I need to use a different wire, like the crank position sensor.


I would love to be able to mimic exactly the electrical circumstances that take place when I turn the key back a notch to the ACC position, then back to the run position. This way the car will be ready to fire back up when I release the clutch pedal in 5th gear !

Correct me if i'm wrong fellow ecomodders, but the fuel vapor you're referring to is not going to keep the engine running. The amount of vapor is so minute, that when you shut the injectors off, the engine shuts off.

[lsemple]

Originally Posted by steffen707

Correct me if i'm wrong fellow ecomodders, but the fuel vapor you're referring to is not going to keep the engine running. The amount of vapor is so minute, that when you shut the injectors off, the engine shuts off.

also,

"I'm fairly certain your car being a 93 civic won't get fuel if you inturrupt the black ground wire that supplies the main relay. That stops the fuel pump and the fuel injectors from getting a signal from the ecu to fire. I did this same setup on my 92 civic, should be the same."




OK perfect, I think you are right about this one, I just like to be absolutely sure about things before I go and start working away and wasting time.

So there is a relay under the hood of my car called "ECU", is it ok to interupt this relay like you said via the "black ground wire", or amy I thinking of the wrong system ?

Thanks again for your help.


Also, second question, why don't people just interupt the wires leading to the ignition on the steering wheel? I had a look at them they are fairly heavy guage, but with a big enough relay and long wire, it could be done.



so,

[steffen707]

Originally Posted by lsemple

So there is a relay under the hood of my car called "ECU", is it ok to interupt this relay like you said via the "black ground wire", or amy I thinking of the wrong system ?

Thanks again for your help.


Also, second question, why don't people just interupt the wires leading to the ignition on the steering wheel? I had a look at them they are fairly heavy guage, but with a big enough relay and long wire, it could be done.

Oh boy, first I suggest getting a manual for your car from an auto parts store, or download the actual factory manual online in pdf format.

The relay you want isn't under the hood, and its not called an "ecu" relay, the ecu stands for engine control unit, often called ECM or engine control module. Its the brains that run the engine and have every sensor hooked up to it.

The relay you want is called the "main relay", and its either on the driver or passenger side of the car up by the dash. On 88-91 civics it was on the driver side, on my 97 civic its on the passenger side. Not sure about 93s though.

You don't want to cut the ignition wires because the car will still inject gas into the engine, although briefly I suspect. Also you don't want to cut those wires because they are big, its more complicated to run a huge relay and wires to shut the car off this way.

its much easier to inturrupt the black ground wire of the main relay.

[lsemple]

OK thanks, I know which relay it is I was playing with it the other day. I just mis-understood your question.



ok so this is my goal.

going to get a 12V 2pST relay, and a 2P2T rocker switch (on-off-on),



I will be putting the relay on the clutch pedal switch and connecting it to 12V accessories power, so when the clutch is depressed the relay is deactivated (the clutch pedal switch is a normally ON switch <normally closed>).


the 2p2t rocker switch will turn my engine-cut-off circuit On or Off, or Disabled.


when the circuit is DISABLED, the clutch pedal switch resumes normal operation via the one of the poles on the relay (prevents car from starting when in gear), and the Engine Kill circuit is shorted out.

when the circuit is OFF (center position of switch), nothing works (anti-theft device),

when the circuit is ON, the other pole on the relay (relay is activated by the clutch pedal), will cut power to the MAIN RELAY which will kill the engine !.


So driving down the road, I can press the clutch pedal all the way down and it will kill the engine, I can start it by releasing the clutch pedal.

I can drive normally by not pushing the clutch all the way in.


I might have another momentary push button bypass switch also which can allow me to flip the toggle switch from ON to Disabled without killing the engine OR use the clutch pedal without killing the engine. This push button will be on my shifter knob.


EMAIL ME if you would like this circuit diagram, I think I have it mastered.

THought I would share my thoughts