Great security system idea!
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Senior Member
Joined: Oct 1999
Posts: 6,621
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Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
Great security system idea!
My friend has a slow burn fuse wire into his car. If he doesn't bypass it then the dies after like 3 minutes driving. How do I build one of these units? I think it would be great for insurance since the car would be stolen since it moved.
------------------
, Jon (350 TBI!)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)
------------------
, Jon (350 TBI!)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)
- Holley 670 TB unit w/ 1/2" spacer/adapter
- Edelbrock RPM vortec intake
- 350ho 330hp vortec crate motor
- 8" harm. balancer
- Stewart stage 2 water pump w/160 thermo
- SLP tri-y headers to full 3"
- Rebuilt trans w/ SLP shift kit
- Centerline 16x8's all around
- 36/24 mm sway bars
- Full poly bushings, even motor mounts
- SLP LCA and panhard
- Alston SFCs
- Edelbrock 3 point STB
- Global west steering brace aka wonderbar
- Eibach pro kit springs
- Bilstien high perf. struts and shocks
- All this and I still have AC
Member
Joined: Jul 2000
Posts: 461
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From: Warrenton, VA U.S.A.
JPrevost,
I agree with your idea, but not for the same reasons.
I designed and built my alarm system that is reliable and simple. After living many years in Central America, I was very aware of car hijackings (person with a gun forcing the driver to get out of a running vehicle and stealing it). While the risk is less here in the U.S., it is a possibility nevertheless. My circuit addresses that possibility, and also to the scenario of just a regular theft. Often, a vehicle will be stolen in a “safe” area, where the chances of being detected or noticed are small. Since my alarm will not activate until a predetermined delay, the idea is to have the person drive a short distance (in my case, I have it set for 40 seconds), at which time the alarm will activate and deactivate the vehicle. I would hope that would be in the middle of traffic. Now the thief has two choices, stay with a disabled vehicle (possibly in the middle of traffic with people looking at him) that is making a lot of racket and try and fix it (and hope the police do not come), or get out and leave. Of course, the latter is what I expect (human nature).
The first vehicle I did this to was my Toyota Land Cruiser FJ40 in 1985. It was carburated, so I simply had a fuel solenoid in line with my fuel line, wired to a latching circuit. With the solenoid off, fuel would not flow to the carburetor. The solenoid is normally off (valve closed). When the engine was started, it would run for about two minutes, because of the fuel in the float bowl, and then stop. So every time I started the engine, I’d have to press a hidden switch to latch on the fuel solenoid. After several weeks, this became habit, so I rarely forgot to do it. If so, it’d just sputter a little and I’d then remember to turn it on. If someone tried to take the vehicle from me, I’d turn on another switch to latch the solenoid off. The thief would get in and drive away. 1-2 minutes later and the vehicle would be “out of gas”. I should have wired it to automatically latch the solenoid off whenever the door was opened, because having to press a switch during a stressful situation would not be as reliable.
With my ’91 Z28, I designed a better circuit that works similar. I made my circuit so that it would activate, or begin the delay to turn on the alarm, any time either door is opened or the engine started. The door will pulse it to begin the delay, at which time I’ll press the reset switch. Since the door only produces a pulse (vice continuously “on”), the door can remain open as long as I want with the car running (e.g. to check my mail) as long as I hit the reset switch. Since starting the car will also pulse it to being the delay, any time I start the car, I have to press the reset switch to keep it off. If someone forces me out of the vehicle with the engine running to steal it, opening the door will being the delay. If I am forced out of it with the engine off, starting it will also start the delay, provided they do not find the reset switch to stop the delay (not likely).
I am not going into detail about the specifics of my system, but after the initial 40-second delay, the alarm will make a unique racket and flash brake lights in a unique manner. The engine will still operate, but in a severely degraded mode. This will happen for about eight seconds. The purpose of this degraded mode is to allow the person to drive out of traffic safely, and not suddenly left in a vehicle without power steering and brakes, possibly in the middle of traffic. Then, the final cycle will disable everything and continue making a racket and flashing the brake lights (hopefully alerting passerby’s/police (could I be that lucky?) in a manner that draws attention. Once the delay begins, the only way to restore normal operation is to activate the reset switch. There is another hidden switch that resets the last two cycles. Disconnecting the battery will not reset it. It’ll turn everything off, but once power is restored, the problem will resume.
The whole idea is to draw attention to the vehicle. The last thing a thief wants is attention. When I first put the circuit in, I would sometimes forget to hit the reset switch. 40 seconds later, the car would being it’s routine. On more than one occasion, people would be looking at me from all locations! I didn’t want to settle for the standard alarm sound because no one pays attention to it anymore. Well, after a couple embarrassing moments, I modified the circuit so that a Sonalert™ would sound (softly!) ~20 seconds into the delay to alert me that the alarm is imminent, and if I don’t hit that reset switch soon, the car’s going to stop…
I couldn’t do the fuel solenoid trick like I did with my FJ-40 becaue I have TPI. But there are numerous ways to make the engine run roughly, yet not die completely, to allow for a safe stop.
Of course, there’s always the scenario of a hijacker getting into the car with me and forcing me (kidnapping) to drive it until he is satisfied that there is nothing wrong with the car, and then drive off. But then anytime the door is opened, it’ll begin the delay.
One of the keys to this system being secure is having the reset switch well hidden. This is where a good imagination comes in handy. There are several types of switches that can serve as a reset switch. When I had my FJ-40 (in Central America), I had another alarm armed by a magnetic which I would pass over a reed switch. There was nothing visible to the eye because the reed switch was behind the window. That worked well until one of the kids that “watches” vehicles (it’s a third-world/cultural thing) while you are away from it correctly guessed how I disabled the alarm. This kid would always “watch” (“guard”) my vehicle (to keep it from being stolen in exchange for a gratuity) while I went into the local supermarket, and he noticed how I would always pass my hand over the same area every time I returned. I guess he noticed the small magnet on my key chain (smart kid!). I subsequently changed that switch to by an RF remote system. Another possibility would be a touch circuit. Two pieces of metal that are touched by your finger will complete the circuit. That could be two screw heads mounted on insulated material.
To answer your question specifically about using a 3 ampere slow-blow. It sounds feasible, but you’d probably have to experiment with different ratings to see which value will work, to give you the amount of delay that you want. Don’t be surprised to find some values close to the rating of the motor to work for many minutes.
I’d imagine that you’d have to splice a 3AG (1.25 x 0.25 glass) fuse into the line, since I’ve never heard of an ATC (automotive blade type) type fuse being available in a slow blow rating. I would imagine the fuel pump would be a good device to start with. Once the fuse blows, the pump stops, stopping the car.
One problem I can see doing it that way is that you’ll have to make a device that will not only latch it on and off (short the slow blow fuse to take it out of the circuit), but also automatically latch it off whenever you turn the car off. If it doesn’t automatically latch off whenever the car is off, and you used a simple on/off switch to bypass the slow blow fuse, you would have to remember to turn it off every time you turned the car off. Myself, it would not only be a hassle, but I would not trust myself to always remember.
To use a latching circuit, I’d do it using an SCR, relay and push button switch. The relay would short out the slow blow fuse to remove it from the circuit for normal operation. If the relay contacts do not short out this fuse, then it will open after a short delay. Then all I’d have to do would be to press this hidden push button every time I started the car to keep it from timing out and disabling the fuel pump. It would be latched off automatically every time the ignition is turned off.
NOTE: Ensure that the wire you open from the fuel pump is AFTER the oil pump switch. On my ’91, the wires go along the left side kick panel to the pump, so pulling up the carpet there would be a good access point.
Before you cut any wires, I would suggest that you test the circuit first. GM used an in-line fuse for my ’91, so that’d be a good point to test. Remove that fuse and substitute a slow blow fuse to determine how long it’ll run for any fuse you are considering. Just short the two sides of the fuse until you are ready to time it. Also determine HOW the vehicle is running run just before the fuse opens. There may be a reduction of voltage because of the resistance of this slow blow fuse. It may or may not be significant. Test it and see. If there is, it’ll cause the pump to run a little slower (and hopefully not cause it any damage). Testing a couple times should not cause any damage.
I know this is a long post, but you did ask...
I agree with your idea, but not for the same reasons.
I designed and built my alarm system that is reliable and simple. After living many years in Central America, I was very aware of car hijackings (person with a gun forcing the driver to get out of a running vehicle and stealing it). While the risk is less here in the U.S., it is a possibility nevertheless. My circuit addresses that possibility, and also to the scenario of just a regular theft. Often, a vehicle will be stolen in a “safe” area, where the chances of being detected or noticed are small. Since my alarm will not activate until a predetermined delay, the idea is to have the person drive a short distance (in my case, I have it set for 40 seconds), at which time the alarm will activate and deactivate the vehicle. I would hope that would be in the middle of traffic. Now the thief has two choices, stay with a disabled vehicle (possibly in the middle of traffic with people looking at him) that is making a lot of racket and try and fix it (and hope the police do not come), or get out and leave. Of course, the latter is what I expect (human nature).
The first vehicle I did this to was my Toyota Land Cruiser FJ40 in 1985. It was carburated, so I simply had a fuel solenoid in line with my fuel line, wired to a latching circuit. With the solenoid off, fuel would not flow to the carburetor. The solenoid is normally off (valve closed). When the engine was started, it would run for about two minutes, because of the fuel in the float bowl, and then stop. So every time I started the engine, I’d have to press a hidden switch to latch on the fuel solenoid. After several weeks, this became habit, so I rarely forgot to do it. If so, it’d just sputter a little and I’d then remember to turn it on. If someone tried to take the vehicle from me, I’d turn on another switch to latch the solenoid off. The thief would get in and drive away. 1-2 minutes later and the vehicle would be “out of gas”. I should have wired it to automatically latch the solenoid off whenever the door was opened, because having to press a switch during a stressful situation would not be as reliable.
With my ’91 Z28, I designed a better circuit that works similar. I made my circuit so that it would activate, or begin the delay to turn on the alarm, any time either door is opened or the engine started. The door will pulse it to begin the delay, at which time I’ll press the reset switch. Since the door only produces a pulse (vice continuously “on”), the door can remain open as long as I want with the car running (e.g. to check my mail) as long as I hit the reset switch. Since starting the car will also pulse it to being the delay, any time I start the car, I have to press the reset switch to keep it off. If someone forces me out of the vehicle with the engine running to steal it, opening the door will being the delay. If I am forced out of it with the engine off, starting it will also start the delay, provided they do not find the reset switch to stop the delay (not likely).
I am not going into detail about the specifics of my system, but after the initial 40-second delay, the alarm will make a unique racket and flash brake lights in a unique manner. The engine will still operate, but in a severely degraded mode. This will happen for about eight seconds. The purpose of this degraded mode is to allow the person to drive out of traffic safely, and not suddenly left in a vehicle without power steering and brakes, possibly in the middle of traffic. Then, the final cycle will disable everything and continue making a racket and flashing the brake lights (hopefully alerting passerby’s/police (could I be that lucky?) in a manner that draws attention. Once the delay begins, the only way to restore normal operation is to activate the reset switch. There is another hidden switch that resets the last two cycles. Disconnecting the battery will not reset it. It’ll turn everything off, but once power is restored, the problem will resume.
The whole idea is to draw attention to the vehicle. The last thing a thief wants is attention. When I first put the circuit in, I would sometimes forget to hit the reset switch. 40 seconds later, the car would being it’s routine. On more than one occasion, people would be looking at me from all locations! I didn’t want to settle for the standard alarm sound because no one pays attention to it anymore. Well, after a couple embarrassing moments, I modified the circuit so that a Sonalert™ would sound (softly!) ~20 seconds into the delay to alert me that the alarm is imminent, and if I don’t hit that reset switch soon, the car’s going to stop…
I couldn’t do the fuel solenoid trick like I did with my FJ-40 becaue I have TPI. But there are numerous ways to make the engine run roughly, yet not die completely, to allow for a safe stop.
Of course, there’s always the scenario of a hijacker getting into the car with me and forcing me (kidnapping) to drive it until he is satisfied that there is nothing wrong with the car, and then drive off. But then anytime the door is opened, it’ll begin the delay.
One of the keys to this system being secure is having the reset switch well hidden. This is where a good imagination comes in handy. There are several types of switches that can serve as a reset switch. When I had my FJ-40 (in Central America), I had another alarm armed by a magnetic which I would pass over a reed switch. There was nothing visible to the eye because the reed switch was behind the window. That worked well until one of the kids that “watches” vehicles (it’s a third-world/cultural thing) while you are away from it correctly guessed how I disabled the alarm. This kid would always “watch” (“guard”) my vehicle (to keep it from being stolen in exchange for a gratuity) while I went into the local supermarket, and he noticed how I would always pass my hand over the same area every time I returned. I guess he noticed the small magnet on my key chain (smart kid!). I subsequently changed that switch to by an RF remote system. Another possibility would be a touch circuit. Two pieces of metal that are touched by your finger will complete the circuit. That could be two screw heads mounted on insulated material.
To answer your question specifically about using a 3 ampere slow-blow. It sounds feasible, but you’d probably have to experiment with different ratings to see which value will work, to give you the amount of delay that you want. Don’t be surprised to find some values close to the rating of the motor to work for many minutes.
I’d imagine that you’d have to splice a 3AG (1.25 x 0.25 glass) fuse into the line, since I’ve never heard of an ATC (automotive blade type) type fuse being available in a slow blow rating. I would imagine the fuel pump would be a good device to start with. Once the fuse blows, the pump stops, stopping the car.
One problem I can see doing it that way is that you’ll have to make a device that will not only latch it on and off (short the slow blow fuse to take it out of the circuit), but also automatically latch it off whenever you turn the car off. If it doesn’t automatically latch off whenever the car is off, and you used a simple on/off switch to bypass the slow blow fuse, you would have to remember to turn it off every time you turned the car off. Myself, it would not only be a hassle, but I would not trust myself to always remember.
To use a latching circuit, I’d do it using an SCR, relay and push button switch. The relay would short out the slow blow fuse to remove it from the circuit for normal operation. If the relay contacts do not short out this fuse, then it will open after a short delay. Then all I’d have to do would be to press this hidden push button every time I started the car to keep it from timing out and disabling the fuel pump. It would be latched off automatically every time the ignition is turned off.
NOTE: Ensure that the wire you open from the fuel pump is AFTER the oil pump switch. On my ’91, the wires go along the left side kick panel to the pump, so pulling up the carpet there would be a good access point.
Before you cut any wires, I would suggest that you test the circuit first. GM used an in-line fuse for my ’91, so that’d be a good point to test. Remove that fuse and substitute a slow blow fuse to determine how long it’ll run for any fuse you are considering. Just short the two sides of the fuse until you are ready to time it. Also determine HOW the vehicle is running run just before the fuse opens. There may be a reduction of voltage because of the resistance of this slow blow fuse. It may or may not be significant. Test it and see. If there is, it’ll cause the pump to run a little slower (and hopefully not cause it any damage). Testing a couple times should not cause any damage.
I know this is a long post, but you did ask...
Junior Member
Joined: Dec 2000
Posts: 11
Likes: 0
From: Texas
Find the main elecric feed to your distributor...splice into it and put a switch in the middle....hide the swtich...guess what when the switch is off the car will act like it has a dead battery...just have to hide the switch well thats all.
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