Does anyone here or has anyone ever thought about putting a hidden toggle switch in as a kill switch? I was thinking about putting a toggle under the dash to stop anyone who gets ahold of my keys. Does anyone know how I can do this? I want it to it'll crank but not turn over. Thanks.

 

Well I can't give you the answer you are looking for... however I work on hotrods and streetrods a lot of the time including our own. No one likes a stolen car, so kill switches and other anti-theft devices are pretty common amongst those rides. I can only suggest a few decent places to be able to place a switch to stop the vehicle from starting, while still cranking...
1. As most rods I work on run EFI or electronic fuel pumps, you just either place the kill switch on the positive or negative side of the signal wire to the pump or pump ecu.
2. Another option would be like the do on the carb'd motors is place a switch between the signal wire to the ignition coil, however on a DIS (distributor-less ignition system), we don't run 1 coil, we run 8 of them, so maybe they share a similar ground or something. Maybe you could look into putting a switch inline with the ECU 12v power.
3. You could place a switch in the crank or cam sensor circuit which would also not allow the vehicle to start
4. And not least.... If you've ever had the plastic/leather cover off around your ignition cylinder, you will see a couple of wires going to it. Try unplugging the bottom one that clips into the ignition cylinder, I believe it's the ground, and if it's unplugged it will not allow the computer to read the programmed number in the key, and the vehicle will just crank all day long. Maybe you just elongate that wire, tie a switch into the glove box so you can lock it, and if that switch is open, the can crank for 20 min., but the vehicle will never twist over..... Ask me how I know...

Me personally.... I would go with no. 1 or 4, just for simplicity and no need to do a lot of engineering, all you doing in opening up a vital information line causing something to be missing from the equation. I really hope someone else chimes in, otherwise I'll try to help as best as I can. I know these Lexus are next to perfect as far as anti-theft, however if someone has your keys, that's all out the window. Just my 2 cents. Hope it helps... By any chance are you close to Carlisle or Mechanicsburg, I was just there for a Corvette show last month, those Turn pikes will make you go broke in a hurry...

 

Thanks man. I just always worried about something happening to my car. So whatever I can do to stop problems would be great This really helps me!


I'm out towards pittsburgh. but I'm only like 3-4 hours from carlisle. I plan on having my car there this year

 

FYI, crank and turn over is the same thing

Kill power to the fuel pump.

But your reason to installing a kill switch is a little odd, where do you normally leave your keys that makes you want to do this?

 

Actually these cars use a returnless fuel system. The fuel rail is still pressurized even after the car is off. If you put a relay on the fuel pump, they know because the car will start and run for a few seconds and then sputter out lol. If someone is really wanting to steal your car and notices the sputter out, then its an obvious give away that it's the fuel pump relay cut. Well...thieves that know how to diagnose a car will know lol. He can follow back to the pump relay and reconnect it. Granted this is probably above the skill level of most casual car thieves(the ones that steal by acquiring the keys instead of actually breaking in and hotwiring). The fuel pump kill will deter most that physically take your keys.

I highly advise against putting the kill switch inline with the crank / cam. Those are very sensitive signals that require shielded cables. If you hook up a extension wire going through a switch(all unshielded unless you buy the $$ ones) you will degrade the signals severely if your parts aren't up to par. This can cause random misfire and even loss of power if the ECU is missing timing data occasionally.

Putting the kill switch on the ECU is a possibility with one caveat. Everytime you pull the power to that ecu it also resets the learning curve on the ecu as well as a few logged parameters. I think it might also erase the clock, radio, and seat memory(it's been a while since I've done that so I'm not 100% sure on that one).

If you want the best option IMO, I would put the kill switch in line with the key transponder signal wire. If ecu does not pick up a key transponder signal, the starter will crank and crank but the ecu will never inject any fuel.