Thoughts on adding a diff locker switch as an engine immobiliser? (1 Viewer)

[bart0]

Greetings all. In a bid to add a little extra security to my new pride and joy, I was considering options for a simple engine immobiliser. I've read a few threads about how to achieve this, with the simplest, i.e. less error prone, being to but power to the ignition with an immobiliser switch (as opposed to cutting the fuel pump?). I'm considering a way to have the default behaviour that ignition starts as normal, but for when I leave it for a longer time/higher risk area I can switch to have it immobilised. Would the turnable locker switch be a good option for this? I suppose any option A/option B switch would work, but thought the diff locker switch would look OEM and not be an obvious immobiliser.

Thoughts/downsides?

Cheers!

 

[Pascoscout]

So long as you can isolate a circuit through the switch that switches on and off a relay you could make it work. It would look factory but also might look odd if you have to turn the locker on to have it immobilized. That alone could draw attention to anyone who knows these vehicles. You could overcome that with a normally open relay (ie would be off when the switch was off).

 

[bart0]

Hi Thanks for your replay. Did not consider someone noticing the position of the diff lock switch. Maybe best to have an on/off type switch instead. I'll have to find and OEM one I can install.

 

[landtank]

A momentary switch works great. Years ago when I drove a company car they had kill switches installed that utilized the light horn switch. To start the car you had to pull the light stock toward you as to flash someone.

The switch for the circuit was hiding in plain sight.

 

[bart0]

Oh that’s a cool idea. I’m not an electronics person, but I assume this doesn’t affect the high beams in any way? And also assume this is just to connect the starter motor/ignition circuit, so once the car is running using the high beam stalk doesn’t affect anything?

Neat trick!

 

[Rusty Marlin]

My old pickup came with a hidden micro switch behind the in dash drink holder that killed the fuel pump.
Worked really well.

 

[Pascoscout]

Oh that’s a cool idea. I’m not an electronics person, but I assume this doesn’t affect the high beams in any way? And also assume this is just to connect the starter motor/ignition circuit, so once the car is running using the high beam stalk doesn’t affect anything?

Neat trick!

As long as you picked the right wires using the high beams would not impact anything once the car was started. I'd wire it to the circuit that goes from the ignition switch to the start solenoid. The circuit would only be energized when the key was in the START position so any other time closing your kill switch would do nothing as nothing was passing through that circuit.

 

[bart0]

My old pickup came with a hidden micro switch behind the in dash drink holder that killed the fuel pump.
Worked really well.

I’ve read about the fuel pump kill switch. How exactly does this work? Is there enough fuel in the lines to get the car started and drive a little way orr does it not start at all?

 

[Mark W]

I’ve read about the fuel pump kill switch. How exactly does this work? Is there enough fuel in the lines to get the car started and drive a little way orr does it not start at all?

It's fuel injected. So, no.

Mark...

 

[Mark W]

Greetings all. In a bid to add a little extra security to my new pride and joy, I was considering options for a simple engine immobiliser. I've read a few threads about how to achieve this, with the simplest, i.e. less error prone, being to but power to the ignition with an immobiliser switch (as opposed to cutting the fuel pump?). I'm considering a way to have the default behaviour that ignition starts as normal, but for when I leave it for a longer time/higher risk area I can switch to have it immobilised. Would the turnable locker switch be a good option for this? I suppose any option A/option B switch would work, but thought the diff locker switch would look OEM and not be an obvious immobiliser.

Thoughts/downsides?

Cheers!

You are only worried about it when/if the rig is left for a longer period of time. There are so many simple ways to disable the rig I won't even try to list them. No need to go to the effort of modifying/retasking any of the switches on the dash.
Pull the EFI relay. Pull the ignition fuse (or swap a dead fuse in...). Pull the coil wire. get the idea?

Sure a knowledgeable Cruiser Mechanic could figure out what you had disabled.

Disable more than one system. Given time, a knowledgeable Cruiser Mechanic could still figure it out.

Of course a serious thief could just back a slideback up to your rig and be gone in moments too.

There are probably more thieves using slidebacks than there are Knowledgeable Cruiser Mechanics out there stealing '80s

Mark...

 

[Rusty Marlin]

I’ve read about the fuel pump kill switch. How exactly does this work? Is there enough fuel in the lines to get the car started and drive a little way orr does it not start at all?

No fuel pressure was created, so it would just sit there and crank.
That truck energized the fuel pump at the ON or RUN key position, if you listened for it you could hear it whine then stop when there was fuel pressure. With the switch activated, the pump wouldn't turn on.

With the Toyota system, it should be as easy as switching one leg of a crank sensor to ground; if the crank sensor(s) don't see engine rotation the fuel pump doesn't fire.

 

[jonheld]

if the crank sensor(s) don't see engine rotation the fuel pump doesn't fire.

That depends on the engine. The 3FE fuel pump runs off the starter circuit.

As Mark mentioned, there's no such thing as an "anti theft" device. Only a device to confuse the knuckleheads. Personally, I like the idea of allowing the starter to crank and cutting off the EFI or fuel pump. This allows the truck to make noise.

 

[USMCDocJ]

A momentary switch works great. Years ago when I drove a company car they had kill switches installed that utilized the light horn switch. To start the car you had to pull the light stock toward you as to flash someone.

The switch for the circuit was hiding in plain sight.

Do you (or anyone else) have more info (i.e. schematics or a walk through) on how one would do this on a 91 with a 3fe? It's an elegant solution IMO.