I have a TRD ECU but...

[firehawk]

89661-AE851? Yeah, we had one of those on our AE82 FX GT racecar and the top board had an EPROM marked 'RALLY4'. It was mapped for 250cc/min injectors, 10.8:1 compression ratio, 304/7.5mm intake cam and 288/7.5mm exhaust cam. Basically what's on the TRD Bible for Gr.A rallycars.

We tried to find differently mapped EPROMs but couldn't find any. Some other people here in Finland with the same ECU had also the same 'RALLY4' EPROM as we did. I intended to extract both the data EPROM and the program EPROM (marked '001' in our ECU), disassemble the code and see if I could reprogram the maps myself but we sold the car and I didn't get very far with my project..

The CPU driving the TRD ECU is a Motorola MC6800 clone by Hitachi so there should be plenty of tools available for hacking around with this now over 30-year old CPU. The other big chip on the board is a HD6821 PIA and its datasheet can be easily found on the net. The rest is just glue logic.