Making my own OBD 1/2 Cable for 95 Z

I am getting a laptop soon and would like to use freescan to sart, then move on to LT1 Edit. The cable prices i have seen are outrageous! Is there anyway i can make my own interface cable to work with my OBD 2 connector and OBD 1 computer? Even if i have to solder it in and i has to saty in the car that is no problem. Thanks in advance!

Yes you can! The circuit is very simple to build, if you know how to solder a bit. Most of the parts are available at Radio Shack Except for the MAX232 chip. I have at least 20 of those chips running around here. I can let these go for $3.00 each, including shipping.

I built the circuit from Andrews BM ALDL Page http://www.akmcables.com/aldl.htm. This circuit does work well. but it has way too many pieces for the novice.

So, I built another one based on a simular circuit for another purpose (If I tell you what, I'll have to kill you). Here is a link to the simplified schematic http://www.mulestomp.com/zapschematic.html
The diode is a 1N4148 or 1N914. The capacitors can be 1uf to 10 uf. This circuit needs a stable 5 volt power source. This can be obtained from a ps2 keyboard port.

Your new laptop MUST have a standard serial port! I bought a laptop 6 months ago and it didn't have one. I tried a USB/Serial adapter from Belkin, it didn't work. The software for PCMs out there is written to directly address the serial port in the computer.
The Belkin creates a virtual com device in windows.

So now I'm using an old Pentium 75 laptop for the free software.

Hope this helps!

Jon

I dont personally feel that $65 is outrageous, but to me its worth its weight in gold for what it enables you to do. Just think if you had a Mustang, I dont know of any real programming options for them under the $500 range.

You do not need an OBD II connector, you can slide the pins into the appropriate lead, or solder if you wish. I just keep using the pins and leave it in the car.

I built the first circuit for $12 and the second for $7. The price diference there is worth a little labor to me. These circuits are the same as the $65 cable. Used with freeaware this is hard to beat.