Mm unfortunetly its not so simple... The engine is in a 1988 MR2 NA has a large port 16valve 4age, I know the smallport (slightly different ECU) uses a system called the TCCS(Toyota Computer Control System), which is a form of OBDI.

Quote:
OBDI is not a standard. While most people refer to cars that aren't OBDII as OBDI, there were no specifications set forth as "OBDI". Cars not manufactured to OBDII spec were not required to adhere to any rules as far as the design of ECU communications. Each manufacturer was free to create there own way to 'talk' to the ECU.

The mr2 isnt really even OBD1 except for its ability to have a check engine light and save error codes... very old school. We dont even use an OBD reader to get codes. You just jump two terminals in a small black plastic box labeled "DIAGNOSTIC" and the engine light blips so many times to tell what code it is.

 

The 4age got the TCCU in 1986. No OBD-I Toyota has an OBD-II compliant diagnostics port.
All OBD-I Toyota TCCU's use a propriatary Vetronhix scanner for the one data port in the diagnostic port.
Without the scanner (about 6 grand for the cheap one), all information must be logged by hand through the DLC<s>.



Toyota calls it OBD-I in their own service manuals.

 

Hmm then i wonder why guys are having so much trouble. Im going with megasquirt there are laready write ups onhaw to do it all for my car.