Immobilizer / Anti-Theft / Kill Switch

[cycleguy55]

I've been thinking about adding an electronic immobilizer, but concerned about another electronic device that could fail and leave me stranded. My thoughts therefore went to mounting a simple switch somewhere on the car I could flip when parking it. I have locking hood latches, so mounting it somewhere under the hood somewhere seems like a reasonable approach. I have read where others have mounted them under the dash so they're readily accessible and therefore more likely to be used.

What are people using? Pros and cons of different devices and/or locations?

[twobjshelbys]

My car had a manual battery shutoff switch with a plastic key. Served the purpose. Since the batteries were right behind the seat it was easy to reach. I've seen others mounted on the dash.

PS. I don't think I've ever heard of a Cobra being stolen from a parking lot while at lunch... They're just not the kind of cars thieves jack.

[patrickt]

Most thieves can't drive a stick anymore. If you have a MSD unit, the box is wired to enable a "kill switch" with the existing wiring. Mucho simple. And if you really want to discourage someone from driving off with your car, get a quick release hub and take the steering wheel with you.

[cycleguy55]

Originally Posted by patrickt

Most thieves can't drive a stick anymore. If you have a MSD unit, the box is wired to enable a "kill switch" with the existing wiring. Mucho simple. And if you really want to discourage someone from driving off with your car, get a quick release hub and take the steering wheel with you.

Nothing that I can see in my instructions that specifically identify a switch other than the ignition switch. The only logical place to connect a switch would be in the circuit from the ignition switch (small red wire). Cut that and route it through the kill switch to kill the MSD input from the ignition switch.

Best place to install the switch? Under the hood? Under the dash?

[patrickt]

Originally Posted by cycleguy55

Nothing that I can see in my instructions that specifically identify a switch other than the ignition switch. The only logical place to connect a switch would be in the circuit from the ignition switch (small red wire). Cut that and route it through the kill switch to kill the MSD input from the ignition switch.

Best place to install the switch? Under the hood? Under the dash?

The MSD instructions show you that grounding the white wire, or purple wire, through a switch will act as a kill switch (the color depends on how your distributor is installed). It's simple and easy.

[cycleguy55]

Originally Posted by patrickt

The MSD instructions show you that grounding the white wire, or purple wire, through a switch will act as a kill switch (the color depends on how your distributor is installed). It's simple and easy.

Not in 6AL instructions. If you can find it you're a better man than me. https://documents.holley.com/6425.pdf

I'll check the instructions for some of the other MSD boxes.

Edit: Found the reference in this document, which supposedly also applies to 6AL. Seems odd this isn't in above-referenced document if it applies to 6AL. https://documents.holley.com/6430.pdf

THEFT DETERRENT
The MSD provides the opportunity to easily install a theft deterrent kill switch (Figure 4).
White Wire Trigger
When using the WHITE wire to trigger the MSD, install a switch across the magnetic pickup VIOLET wire to ground. When the VIOLET wire is grounded, the vehicle will crank but not start.
Magnetic Pickup Trigger
When using the mag pickup to trigger the MSD, install a switch to the WHITE wire and the other side to ground. When the WHITE wire is grounded, the vehicle will crank but will not start.

[patrickt]

You know I remember that now, it seems MSD included the instructions in some instruction sets, but not in others. Anyway, it will work. Try it.

[cycleguy55]

Originally Posted by patrickt

You know I remember that now, it seems MSD included the instructions in some instruction sets, but not in others. Anyway, it will work. Try it.

BTW, I totally agree most of today's criminals would have a problem with a Cobra: 1) manual transmission; and 2) carburetor instead of fuel injection - especially if a cold start.

My ignition box is actually a Summit Racing box, supposedly built by MSD. The MSD 6AL and Summit instructions are almost exactly the same, so I'd expect the kill switch wiring would work the same way, but I've reached out to Summit to confirm. Thanks for the info, BTW.

Not asking you to give away any secrets, but - best location for switch?

[patrickt]

Originally Posted by cycleguy55

Not asking you to give away any secrets, but - best location for switch?

Anywhere that is easily reachable under the dash, while you're sitting behind the wheel, and doesn't draw attention to the fact that you're doing it.

[1795]

My ERA had a battery disconnect switch in the trunk near that battery. It was keyed so that you could take the key with you and attach it to your key chain. Since the trunk would be locked it would also be a deterrent.

[ERA174]

I connected the white wire from my MSD 6al to a toggle switch mounted on the dashboard, easily accesible in an emergency . The kill switch looks the same as the other toggle switches and no switches are marked as to their function, hidden in plain sight. If you want to go all James Bond stealthy with the switch, use a magnetically actuated reed switch. I did this on a truck I had when I worked in a bad part of town. I mounted the reed switch behind the head liner which controlled a relay that killed power to the electric fuel pump. The magnet was hidden in the driver sun visor. When the sun visor was up against the headliner it would actuate the reed switch, killing the fuel pump. So, if the truck was hot wired it would start and then die when the fuel in the system was depleated due to the fuel pump kill switch rendering the pump inoperable. The sun visor/headliner location would not work in a Cobra, you would have to locate it some other place. The bottom line is, have sufficient insurance to replace the Cobra if it is stolen. If someone really wants to steal it you probably can't do anything to stop them.

[twobjshelbys]

Originally Posted by ERA174

If someone really wants to steal it you probably can't do anything to stop them.

As they say, "Locks just keep honest people honest".

All of these solutions really won't prevent someone from stealing your car if they really want it and have time. They just slow them down and cause them to move on to one they can get quicker.

You don't need to make Fort Knox. Choose whatever solution minimizes your inconvenience as it will be all that is needed.

[TLHanna]

My Backdraft has the electrical cut off that may or may not stop a theft but I added an alarm that will raise hell if the car moves and has a real time GPS locater that sends me texts and emails if the car is moved. Might not stop it but I'll find it if it's ripped.

[dallas_]

I put an under dash switch for my fuel pump. If they can get it started, they won't get far.

[Unique427]

Trunk mounted Flaming River Battery Disconnect (next to battery).

https://www.flamingriver.com/index.p...s014/FR1046LED

Single point Battery disconnect AND alternator cutoff switch available from Flaming River too.

Beyond that and a battery powered GPS locator if thieves want the car they will get it.