I was not talking about killing the ECM, but interrupting the signal that goes to the ECM, like from the ignition switch, or from ECM to the injectors.
Questions About a Simplistic Theft Protection System Idea
- Thread starter Cdn17Sport6MT
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The Fuse panel in my new toyota has two relays for the EFI - one for the MPI and one for the GDI. I wonder if someone makes a normal square automotive relay that has an additional input - to otherwise dirupt it. Like a double pull - single throw - except one of the doubles was a screw terminal on the top or something.
You just need to interrupt the 12V signal to the relay and it will not function. Every relay has an input that’s always hot, that’s the one you need to interrupt. That would probably be the easiest.
Here is a much simpler and safer solution to help protect your vehicle. Just hook this up to interrupt the 12v feed to the fuel pump or fuel pump relay. It can be installed under the dashboard to minimize the wiring run or in the trunk/spare wheel area for greater security. It won't affect any other settings (i.e., ECM & Radio memory)
Remote On-Off Security Switch
Of course, this will not deter the real organized crime car theft rings that steal vehicles in 30 seconds like repo. men with tow trucks that lift the drive tires.
Remote On-Off Security Switch
Of course, this will not deter the real organized crime car theft rings that steal vehicles in 30 seconds like repo. men with tow trucks that lift the drive tires.
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I was going to reply that I would avoid anything operated by a remote, but I see the relay also has a manual switch on it. I think that’s a pretty good device and a pretty good find.
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Right, I think 85 is the "on" pin to the coil, but to interrupt it I need to mess with the factory wiring, which I don't like to do. I would prefer to add something between the 4 factory pins in the panel and the relay, rather than cut factory wiring.
Yeah, I would not want to cut factory wiring either. I would probably use a relay socket. Solder relay feet to the wires so that they can be inserted into the fuse box. It would not look great, but would be dead easy to revert back to stock.
Something like this
If the OP is OK with just using a manual switch, I'd suggest wiring in a SPST on-off switch to interrupt the (-) polarity ground wire at the fuel pump assembly's pigtail. That would prevent having to cut any part of the larger permanent chassis wiring harness and eliminate the potential for a short on the 12V (+) hot leg.
You can even get stealthy and source a factory-like ON-OFF switch that goes in the dash (like an OEM fog light switch) and hide the security switch in plain sight!
You can even get stealthy and source a factory-like ON-OFF switch that goes in the dash (like an OEM fog light switch) and hide the security switch in plain sight!
Simplistic? You mean like the It's my car scene from the movie Death Wish 3?
Thx to All for having answered. The idea of dummy dashboard switches - say even in a logic pattern of some having to be on vs some off... or mebe just a single switch - that has intrigue. The idea of having it start but sputter is an interesting one, too. What intrigues me about the Littelfuse is that a bolt, in essence, is used to complete the circuit. Now yes, it may be possible to jam a screwdriver in there to complete the cct... mebe... but what thief carries around a bolt in his pocket? Also, said "switch" could be flush with the floor... easily missed, even under a flap of the floormats?
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The problem with splicing anything into one of the main voltage wires, such as the battery cable or starter cable is the high current that flows though them. Adding any type of switch or a connection to these simply adds another voltage drop and a failure point. High current connections do not like voltage drops.
Any dirt, corrosion, moisture or not secure enough connection and you can have a big voltage drop or sparking. Neither is good for the electronic in your vehicle.
And since that switch you want to use, will be used often and located under the carpet somewhere, it will be susceptible to dirt, moisture and pure mechanical wear. It's not a good solution for what you want it to be used for. Plenty of better and more reliable solutions were listed for you.
I agree that it should not be used for high current...
