Anti-theft toggle switch across electric fuel pump fuse ????

Hi

I wanted to make an anti - theft setup for my Chevy Express van , 

I thought about a battery disconnect , but when I tried that by taking off the battery cable overnight ,  once I put it back on and started the motor it ran poorly for 5-10 minutes while the computer re-learned  its codes , 

So I thought that I could just  take out the fuel pump fuse  and  put a toggle switch ( with another fuse) across the fuse box slot 

I seem to remember that you could buy a "Fuse with wires" to add a radio etc  , 

its a regular 2 spade fuse , 

Any reasons this would not work ?  

Thanks for your ideas

That would work. You could also interrupt the power to the starter solonoid. 

Neutral safety switch?

I assume the Express already has something like this somewhere, but on the old BMW I ran the Megasquirt's fuel pump power through a Ford (Ford-era Jag, actually, I think) intertia switch. It had an easy to reach reset switch which you could easily pull up to disconnect the pump, and as a bonus, it'd shut down the fuel pump in a wreck (again, I'm guessing the Express already has one).

I wonder whether the Express' switch is located somewhere you could just use it? I guess it might even be done in software, depending on what year...

I used to work with a guy a timer/relay for the fuel pump and a little pushbutton under the seat.  If you did nothing, the truck would run for 30 seconds and then die (fuel shut off). If you poked the button, it would run normally.  If you went looking for fuel, it had it and the pump was running and then would die.

I did this with my bug eyed sprite, that many years ago. Now I wouldn't bother, it also had the millennial anti-theft device---a clutch!

ProDarwin said:

Neutral safety switch?

I did that aeons ago on my Miata and wrote it up back when we used mailing lists to communicate. Just a switch inline with the neutral safety switch, hidden in the center console. The nice thing about this version is that it won't shut down the car while you're driving, it'll only keep it from starting again.

We found out years later that Mazda had left an easter egg in the car's design where the main relay would fail in a similar manner, amusingly leaving you stranded with a car that had been running perfectly when you turned it off. Oh, those kidders at Mazda.

thedoc said:

I did this with my bug eyed sprite, that many years ago. Now I wouldn't bother, it also had the millennial anti-theft device---a clutch!

You'd think. But some E36 M3head stole one of my cars with a clutch. Given how far the driver seat had been pulled up when the car was found, said E36 M3head could easily have been a millennial, not done growing.

I then wired in a hidden switch in the car that kills power to the fuel pump relay. I didn't want to have something I had to access under the hood. The car starts/runs for ~15 seconds.

Keith Tanner said:

ProDarwin said:

Neutral safety switch?

I did that aeons ago on my Miata and wrote it up back when we used mailing lists to communicate. Just a switch inline with the neutral safety switch, hidden in the center console. The nice thing about this version is that it won't shut down the car while you're driving, it'll only keep it from starting again.

Yeah, for a manual I prefer the clutch safety switch, and you can make it a momentary switch.  The nice thing about that is you can't accidentally leave it in the wrong position.  You just hold it while you crank with your other hand.

In reply to ProDarwin :

Those are very good ideas!

My father did this on his MGTD, and it got seriously tested. It would start and run about a minute on the fuel in the carbs. One day he gets a call from the cops"Why is your MG in the middle of the intersection of Grove & Clairmont?" which was just about a minute from where it was parked next to our shop.....No idea who took it, but they bailed quick when it quit.

ProDarwin said:

Neutral safety switch?

that's how I have my hidden ignition cutoff switch wired (my truck is manual-swapped from an automatic, so I had to jump those wires anyhow). 

I like to run kill switches through factory controls.  Often I'll get some switch for an option I don't have and use that to control the circuit I want to interrupt. 
 

one of my old cars had an extra switch that was redundant so I rewired it to interrupt the starter solenoid wire. 

on my truck it doesn't have rear windows so I bought a window switch panel from a 4-door and am going to use the window lock switch that it has (that I don't need) as a starter interrupt. 

I also use switches to trigger relays to do the same thing 

I wired the fuel pump relay power/signal to an old school floor mounted high beam switch. Put it under the pedals hidden under the carpet.

I had a 70 Impala as a daily driver in the early 2000s and worked in a neighborhood where that type of car was very popular with some nefarious people. Since the door locks were a joke I set up a kill switch. I wired a relay in to the starter selonoid. When the selonoid was powered the car started normally. Since I didn't smoke I used the cigarette lighter to power the solenoid. You had to push in the cigarette lighter to start the car. If I went in somewhere and was worried about the car I'd pull the lighter element out and stick it in my pocket. 

A toggle inline with the fuel pump trigger wire from the ecu to relay is a little more complex, but you can use a much smaller current rated switch and wiring.

I had ideas of a capacitance switch hidden behind a panel. Hold your hand over it and you can start the car. Or something similar with a magnetic switch.

Now days a RFID tag reader could do it either through a key chain or you phone even.