<'95 OBD (or whatever) serial/USB cable, need to connect my Celi to a carPC Options

[quick_5hifter]

Hello everyone!

Last couple of weeks I've been setting up a car PC for my Celica.
The car is a '95 ST202 with the non-VVTi 3sge engine (129kw/175 HP).
The car PC will be permanently installed in the car, so I've been thinking of connecting it to the car somehow, to be able to use it for diagnose and stuff.
I need to know if that is possible for the pre'96 Celicas, if there is any cable available, along with some software. I've done a couple of diagnoses so far, in a specialized garage, so I'm sure the under-hood connector is good for something
If you think / know it isn't possible, do you recommend changing my ECU with some '96+ ECU that runs OBD2? Is it possible to replace the ECU only?
Would it be possible to connect my PC to some "piggy-back" ECU or should I go for some stand-alone engine management system?

PS: I know that I could buy some diagnostics kit for Toyota (including a tester/mini-computer that is specially designed for diagnostics) along with the cables required, but that would cost a fortune so it's out of discussion.

PS2: Didn't find any answer for my questions by using the "Search" function.

Thank you for your time and possible answers!

[mkernz22]

If you got a '96 + ECU, you'd have to change a ton of the wiring in your car as well as convert your engine to OBDII. Too much of a hassle.

[quick_5hifter]

Ok, thanks, it's good to know. So one out, three to go :

1)original ECU (pre '95)
2)piggyback
3)standalone.

Which one is possible and/or better to connect to a car PC? (not easier and cheaper)

This post has been edited by quick_5hifter: Feb 16, 2011 - 9:23 AM