Can I do this to shutoff engine when leaving the car? - A robbery for example

[jvictormp]

I've seen these chinese PKE - suppose it stands for Passive Keyless Enter - systems people use to unlock the car when approaching like 2-3 meters to it. Obviously our Ms wouldn't need that, specially when you have comfort access, which is my case.

https://pt.aliexpress.com/item/10050...archweb201603_

But here in Brazil you may be surprised in a light signal with a guy pointing a gun to you to take your car.

In that case, I want to give the car with the key fob and step away in peace if needed, but I need to have something in my pocket that shuts off the engine as soon as I get far from the car.

So what if I used one of that PKE system output signal that locks the car, to (instead) actually shutoff the fuel pump?

I don't know, maybe put a second relay between the fuel pump relay and the pump itself. When far from the car, that second relay would be de-energized by the PKE, and the pump would never turn on, or would instantly turn off if running.

When close to the car, the relay would energize, and let the system work like it is supposed to.

You guys think that it's possible? Maybe electronically dangerous?

[jellydoughnutt]

I remember years ago when I drove a Honda Civic si with the b16 and lived in a pretty grimy part of town. I had a friend of mine that had his for three weeks... then he walks outside to see his si gone and it scared the crap out of me. I installed a toggle switch that was connected to the file pump. I had the switch cut out and placed sticking out of the middle console behind the front seat. Any time I would get out of my car I would reach back, flip the switch and the car would be disabled.

This would work in your case if you cover one item. How will you get communication remotely to your car if it’s driving away? You will need some sort of cellular communication tied to you vehicle to disable from such a long range.

[jvictormp]

It's not that it need to receive a command to disable the output.

It monitors the presence full time. Whenever you're around, it's on. The right moment it doesn't detect the key presence, it turns off.

[Cyberdemon]

I see what you're getting after - but my immediate concern with attempting to intercept a signal (For example, to turn the fuel pump off) would likely starve the engine for fuel but not necessarily tell it to shut down properly. It may not be that big of a deal, but I'm also thinking "what happens if your secret key just has a dead battery or interference and you then starve the engine for fuel while driving normally".

This is a situation where I would just say isn't it better to just have the car insured and not risk the guy with the gun rolling 5 feet, having the car shut off, and then having him chase back after you to go "what the f*** did you just do?"

[Asianoak]

Originally Posted by jellydoughnutt

I remember years ago when I drove a Honda Civic si with the b16 and lived in a pretty grimy part of town. I had a friend of mine that had his for three weeks... then he walks outside to see his si gone and it scared the crap out of me. I installed a toggle switch that was connected to the file pump. I had the switch cut out and placed sticking out of the middle console behind the front seat. Any time I would get out of my car I would reach back, flip the switch and the car would be disabled.

This would work in your case if you cover one item. How will you get communication remotely to your car if it's driving away? You will need some sort of cellular communication tied to you vehicle to disable from such a long range.

I did a similar kill switch install on an exes car. But we took it one step further. We got an actual switch from a junk yard for an option her car didn't come with, then wired that as the kill switch. Super OEM in look, and 100% effective. Just am idea for anyone wanting a kill switch

[jvictormp]

Originally Posted by Cyberdemon

I see what you're getting after - but my immediate concern with attempting to intercept a signal (For example, to turn the fuel pump off) would likely starve the engine for fuel but not necessarily tell it to shut down properly. It may not be that big of a deal, but I'm also thinking "what happens if your secret key just has a dead battery or interference and you then starve the engine for fuel while driving normally".

This is a situation where I would just say isn't it better to just have the car insured and not risk the guy with the gun rolling 5 feet, having the car shut off, and then having him chase back after you to go "what the f*** did you just do?"

You got a point. I'd also put an "override" switch in the trunk, in case the key had a dead battery. Would stop the car by the side of the road, and switch the override on. Then go home without that protection, replace the battery and turn off the override switch again.

Okay, problem#1 - it could turn off the engine in a corner or something. That's bad, but I think I would take the risk.

Okay, problem#2 - I could have that problem you said about having the guy chasing me, but I can run fast as a bullet (actually would bet against his aiming habilities)

Or I could combine the relay with a timer-off.


EDIT:
Insuring the car costs about 10% of vehicle value a year. And worst, the manual E9X M3s have gone rare and overpriced (like usd 45k), and insurance companies would pay not the market actual value, but a fixed price (usd 25k)
Not a good deal.

[Cyberdemon]

Originally Posted by jvictormp

You got a point. I'd also put an "override" switch in the trunk, in case the key had a dead battery. Would stop the car by the side of the road, and switch the override on. Then go home without that protection, replace the battery and turn off the override switch again.

Okay, problem#1 - it could turn off the engine in a corner or something. That's bad, but I think I would take the risk.

Okay, problem#2 - I could have that problem you said about having the guy chasing me, but I can run fast as a bullet (actually would bet against his aiming habilities)

Or I could combine the relay with a timer-off.


EDIT:
Insuring the car costs about 10% of vehicle value a year. And worst, the manual E9X M3s have gone rare and overpriced (like usd 45k), and insurance companies would pay not the market actual value, but a fixed price (usd 25k)
Not a good deal.

Buy a gun or get a GPS tracker?

[InnerBlueSkies]

I'd either go with a gun or this. It's illegal in America because it violates the rights of would be criminals.