fuel cut off switch - theft device

[GhettoPop]

want to make a fuel cut off switch as an anti theft device for my 90GT. read articles on the fuel relay under the drivers seat (black and green case) as well as the fuel inertia switch in the trunk (unsure of location). whats the best way to set it up? exacly which wire(s) do i splice into? do i need to add a relay? i'm guessing 16 or 18 gauge wire and a 20 amp switch should do????

[GhettoPop]

this seemed helpful:

http://www.veryuseful.com/mustang/te...nks-ign-ac.gif

[PKRWUD]

All you have to do is put a switch in the red/black wire going to the fuel pump relay, under your seat. Decide where you want the switch mounted, cut the red/black wire, and attach a wire to each end of the cut wire, and run them to the mounted switch. This will prevent the fuel pump relay from being activated by the ECM, or by any outside source, unless the switch you install is in the closed position.

[GhettoPop]

so i assume when i cut the red/black wire, i should cut out about an inch or two so a theft cannot just connect the wire I cut and bypass the switch. seems like the switch is very easy to bypass. i will try to run the two wires to the switch on opposide sides of the car

[PKRWUD]

If a thief tries to steal your car, and get's it to crank over, but it won't fire, I doubt they're gonna invest more time to trace the fuel pump circuit. The relay cannot be accessed without removing the seat, but the location of the switch is up to you. You could mount it in the trunk, and cut into the wire near the inertia switch, but then it becomes a pain for you. Not to mention it wouldn't take very long for someone to figure out you have a switch in the trunk, if they observe you coming and going for a day or two.

[7K331]

When my car was new & had to be left in a parking lot or if I left for a few days of vacation, I would just take the rotor out of the distibutor. So what if the theif figured out what it was, who carries and ignition rotor for a mustang in their pocket?

[Hozer 88GTConv]

What are the odds that the FP relay is on the pass strut tower. I haven't found manufacturer's specs as to when they switched the location. Or is it a either-or thing???

Anyway, great little trick to deter punks...

[HISSIN50]

Originally posted by Hozer 88GTConv
What are the odds that the FP relay is on the pass strut tower. I haven't found manufacturer's specs as to when they switched the location. Or is it a either-or thing???

Anyway, great little trick to deter punks...

from what i gather, it was in late 92 and 93's (for fox chassis cars). i figure it is about the time they switched to hypereutectic pistons.

oh, i can get to my FP relay with the seat in the car (88 GT vert).

on the cutoff switch, be careful. if your switch fails, your car will die right then and there. i prefer to do it passively, with an SPDT relay which only energizes if someone tries to start the car (otherwise running through the common and Normally closed terminals). while not bulletproof, the chance of failure is less (but one has to check it periodically, as if it fails, it is likely to not energize and not kill the FP. if the relay fails to energize, which sometimes happens as they age, the car will start).
this is the same idea as a starter kill on an alarm.

[Chris_H]

I actually tapped into the FP relay under my drivers seat, and ran it to the Painless switch panel I have in my ashtray area. Granted its not the most hidden place to put it, but I labeled it with "Nitrous" and labeled the rest of the switches as "Water pump" "Fan" and "Line-lock" The nice thing is, when the key is turned on, none of the lights for the switches come on, and so it looks like everything is off. If they really want to steal the car, they will take it, I just figured I would make it a little more difficult.

Chris

[mustangracer8590]

What i did was i spliced in to a yellow wire on the starter relay in the engine bay and ran a 16 gauge through the firewall into a switch