I was wondering if theres a circuit in the obd1 ecu that i can add a simple immobilizer to?
For example a resistor of certain value that is wired under dash hodden that would prevent it from starting
Or running.

There are unused pins on the harness that could be used for immobilizer circuit?
I dont know exact layout of the ecu but just throwing the idea outthere

 

How would you match it to your key?

 

Not a key
A resistor of specific value as a key.
Instead of using a kil switch use a resistor
I know its not as effective as oem immobilizer but maybe if programmed on the chip
It can prevent the ecu from powering up if the resistor is not plugged in

Just thought it was a possibility to make it harder to steal ecus.

 

NepTune has a more elaborate anti-theft feature for OBD1 ECUs. Check it out.

 

I second that, but someone can still steal your ECU and reprogram it. There's really no way to avoid getting your ECU stolen short of riveting it to the floorboard.
On a side note I'd suggest an RFID chip kit for general theft protection, you can connect the module's output to a relay that intercepts a power wire of your choice. Easy to hide, difficult to hack. You can get a universal programmable RFID kit like Pass Tag for under $100, or a more expensive one for about $250. There's probably a way to incorporate that in the ECU, but they won't know until they steal it anyway.
I embedded my chip in my hand, because I hate carrying keys.

 

You can also make a pretty good rfid setup using Arduino if you are so inclined. I've seen some pretty sweet home-brew antitheft setups in the last couple of weeks while looking around for new project ideas.

This one is my absolute favorite:

http://b.leppoc.net/2011/04/23/operation-lo-jack/

 

Arduino FTW.
And rivet the ECU to the floor.

 

There are lots of things you can easily do...usually multiple layers will help confuse thieves.

#1 - Unplug the dizzy (no spark)
#2 - unplug the dead end connector on the drivers side shock tower (powers the injectors)
#3 - install an inline switch to the power on the main relay, the fuel pump or the output from the ECU
#4 - pull the ECU fuse

...and the list goes on

An immobilizer is to make sure the key in the ignition is the key thats supposed to be there, so if you arent programming a key, then its just a simple solution you need like above

...do the above AND get Neptune RTP

 

Is it possible to emulate obd2 immobilizer? Because we can order chiped keys from honda.

 

You could, in theory, install an RFID circuit in the ECU to intercept certain functions.
But if you need to ask how, you're not qualified to do it.

 

immobiizers are like the easiest thing a theif can defeat...im just having a hard time understand why you are so hung up on this particular idea when there are so many easier to do?

 

Im not hung up.
Why do you assume that thia is the only thing i have in my arsenal
I just wanted to see if we can make the obd1 ecus harder to steal
Yea you can bolt it down
But most likely it they cant steal it they will destroy it.

If they steal it and sell it then find out its not working chances are it might show up on the forum somewhere

 

Ooooh....you are worried about the ECU getting stolen, not the car?

Didnt realize that...

 

But what ever mod to the ecu board can allways be put back to stock. Any smart person with a solder gun. Way better other mods can be done.

 

Here's an idea:

Using an rfid circuit like the one in the link I posted above... make some sort of simple rfid device using an Arduino. Mount the reciever somewhere in the center console. You carry a card/chip in your wallet. Program the arduino so that when it sees the chip it outputs 5V. You'll need to run that to a relay that can then switch on a 12V output. Wire that output to one of the inputs on a NepTune equipped ecu.

In the NepTune software, you can use the anti-theft feature. It has an and/or setting, so you can set it up so that it requires the gas/brake password and/or a selectable input to start. Select the input that you wired the relay to. The car will not start unless you get in it with your wallet (or whatever you attach your rfid chip to) and/or use the password.

Use the stamped metal cover that cam with the obd1 cars over the ecu. This should keep any thieves from being able to get at the connectors to unplug the ecu and replace with one to get the car. To secure it, use breakaway security nuts (like the ones that hold your ignition switch to the column):


or maybe

 

security nuts are for girls, weld that **** to the floor =D