I have a TRD ECU but...

[Rasteirinho]

I think the chip that is fitted is for high duration cams since it belongs to an old Gr. A rallycar.

The chip is fitted over a socket so i can change it.

What i would like to know is if there's available chips for TRD ECU but with softer maps...

Thanks...

[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.

[Rasteirinho]

Hi Jani,

You're right, the P/N is that and it has a top board where the eprom is fitted.

Mine has a sticker with a "1" marked.

I will try to read it using WinOLS, i don't know if i need any kind of checksumm after the modifcations.

Well, considering that i will understand the maps... I've some knowlegde about Turbo Diesel mapping and Honda Petrol engines mapping...

[firehawk]

If you manage to read the contents of both EPROMs into image files, could you send them to me as well? I'd be really interested in seeing what the code looks like and would like to disassemble the program code and analyze it. From that, I should be able to figure out the memory locations of the maps.

IIRC, one EPROM was a 2 kilobyte 2716 and the other one a 1 kilobyte 2708.

By the way, did you get the TRD map selector switch with the ECU? We never had that on ours.

[Rasteirinho]

Nopes, I had only found the ECU.

I thought it was only one eprom with maps (the one fitted to the socket).

I will read it and then send it to you...

[firehawk]

Hmm, the ECU we had used two EPROMs - both were socketed on the top board. From what I was able to find out, one apparently contained all the executable program code and the other one contained the maps and other data. I should have a few photos of the board on my home PC - I'll post them when I get back home from work.

It could be that on later revisions of the ECU the EPROM containing the program code was soldered directly on the board.

Edit; Ok, I remembered incorrectly - the program EPROM (2732 marked '001') _is_ soldered to the board. So in order to dump an image, it would have to be soldered off the board and socketed.

[Rasteirinho]

That ECU is similar to mine...

So, if i want to edit the maps i have to read the eprom that's soldered to the board?

What information is in the eprom that is fitted to the socket (the one with rally marked).

[firehawk]

The actual maps are most probably stored in the socketed EPROM chip ("RALLY4") but it would be very difficult to know exactly which address they're located on within the image. In order to find this out, we'd need to disassemble and analyze the actual program code which the ECU is running and figure out how it accesses the maps. And to be able to do this, we'd also need an image of the program code, which I believe is on the other EPROM ("001"), soldered on the board.

[robokill]

Rast there is one guy here who can map an eeprom. I don't know what his price is but he build his own trd computer.

R.hellenbrand

His name is Ron. He is on this forum. You can ask him what to do in your case? But why run a TRD computer? Its all hard coded which kinda sucks. You can't modify much

[Rasteirinho]

Well, i don't know if i will run it especially because my engine is almost stock...

However, as i found this ECU "abandoned" at my work place, i decided to bring it home before the cleaning lady send it to the garbage.