[ike84]

The push button start actually isn't too challenging if you understand how the ignition switch works. Here's a breakdown of it.

There are 2 12v supply wires coming into the ignition switch(aka "line" in electrical speak) The switch itself is a wiper switch, meaning that as you turn the key out makes contacts with progressively more outputs (aka "loads")

The first and second positions send voltage to the ignition controlled circuits.

The third position sends voltage to the starter solenoid, but only while you have the key all the way over.

Let go of the key, the starter kicks off, but the ignition controlled circuits stay on.

Turning the key all the way to the left and removing it then kills the voltage throughput and shuts everything off (mostly, but that's a different discussion)

So, to mimick this, you need two switches.

The first is a locking switch (push button#1) to control a relay powering the ignition controlled circuits.

The second is a momentary switch (push button #2) to control a relay powering the starter solenoid.

To actually do this you need to completely disassemble the steering lock, removing the ignition switch, key cylinder with inductor ring, and the transponder receiver. Leave the ignition switch connected to the wiring harness and turn it to the 2nd position (all circuits on). Splice in your latching switch relay to the two 12v supply lines (fat red eyes going to terminals marked 30 on the ignition switch). This way, when the latching switch (#1) is open, everything is off. When the switch is closed, everything turns on. Run a wire from the load on that relay to the line on the second relay, and from there to the ignition wire (the fat yellow one). This second relay is then controlled by a momentary switch (push button#2). This way, you have power coming into the relay when the first button is pushed, and then you send voltage to the starter by holding down the second push button.

But wait! What about the transponder?! Easy... Put your key in the lock cylinder. Then tuck it up and out of the way in the dash. Or you can locate it somewhere so that you can easily remove the key. Or, if you're slick (which you obviously are since you've made it this far!) splice a locking microswitch in line with the induction ring wiring and then hide the switch somewhere in the car. Have you seen back to the future? Biff's car had the same thing! (Ish).

You must realize something here. What I've just described bypasses nearly every anti theft feature of the car. No steering column lock, no key, no transponder. Just push push go. BUT, I'm not worried about it. First, no one steals Porsches. Or even tries. Because any good car thief knows that they can't. But what about the idiots? They break my window and then what? Start pushing buttons, hoping they can figure out the ignition sequence, only to find out that the fuel pump won't work if the inductor ring is disconnected by the microswitch, all the while the damn alarm is going off? Whatever idiot finds himself in that position will then get to see what a KelTec KSG looks like...

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