Custom Immobilizer

[Ryan]

So I have been thinking for a while, and I want to install a custom immobilizer. I want to put a switch in my starter circuit, preferably relay operated, because I don't want to run what, 30 amps, through my cabin, or make the wire too long....

Looking at the wiring digram, I could just put the switch into the ignition wire I can't imagine thats a terribly high current wire, it will be just a 12v bias, right? Ijust looked harder, it seems the ignition switch actually closes a 12v circuit allowing a coil to be charged to pull the starter acutator (I don't know the right names?) Does someone with better electrical system knowledge than I know which circuit I should be bustin' into?

I would want to run it somewhere, not sure yet, somewhere hidden obviously and away from the steering column... and make it a little inconspicuous switch, like the valet switch for alarms. I was thinking up by my dome light

Opinions? Where do look for the ignition wire under the hood? Anyone happen to know the colour?

starter page
http://www.mx-3.com/manuals/showimg.php ... _G-033.gif

What is the S terminal for? I think thats the one I will want, no?

[lazzer408]

Hook it to the cas or ignition trigger at the ecu.

[Ryan]

Got an idea what colour that wire may be? Or how I could find out? I don't wanna go hacking at random... for obvious reasons...

[lazzer408]

year, make, model, engine?

[Ryan]

1993 Mazda Mx-3 B6ME SOHC

[lazzer408]

Ignition trigger (output) is pin 1G (green/white), CAS (input) is 2E (white) and 2G (Orange). I'd go with the CAS. That way your injectors arn't firing. You can also disconnect the Light Green wire at the airflow meter. This will cut the main relay and nothing will have power once you release the key (from start).

Aw this car is batch fire injection? I didn't know that. My '94 is sequential.

[Nd4SpdSe]

Could always disable the fuel pump too

[marcdh]

Could always disable the fuel pump too

Yep this way they think they have the antitheft beaten, then the engine dies I think it will confuse them more, otherwise they will look for your switch until it starts.

[lazzer408]

The airflow wire switch will cut the pump as soon as the key is released.

[Ryan]

Could always disable the fuel pump too

I like this idea. Easy access to wire in a switch. Its accessable from the back seat, no? under that silver plate?

[Nd4SpdSe]

Yep this way they think they have the antitheft beaten, then the engine dies I think it will confuse them more, otherwise they will look for your switch until it starts.

Exactly!

I like this idea. Easy access to wire in a switch. Its accessable from the back seat, no? under that silver plate?

Actually, it's accessable on top of that silver plate Also, if you look by your ECU, there's a relay right there, that's thge fuel pump relay, you can go there too

[Ryan]

So say I hide this switch in the backseat, what if someone hits it while I'm driving?

Duh the engine will die, but will it damage anything?