Jinx,

Here are a few pointers:

1. Use Bosch Injectors: they are the best...hands down. You can get a kit to convert both your primaries and secondaries to Bosch style (universal) injectors.
www.k2rd.com

2. Don't tune overly rich. A lot of people think you should always tune rich with rotaries, but its really not necesarry. Remember, peak efficiency (in terms of BSFC) is reached with lambda is approx. 1 (i.e. A/F ratio of 14.3 to 1 or so).

3. Don't your time, or money with plug and play crap. Very rarely do these systems work better then true stand-alone EFI.

4. KEEP DIRECT IGNITION!! Coil on plug ignition is fundamentally better then a dizzy setup.... Even if you would be using an electronic distributor. Use a CDI box if necesarry.

 

I agree with the ignition. I will check out the site about the injectors. Thank for the tip!

 

i fall into the A) and C) catagories.

I've been doing chip tuning for years.. CA18, SR20, RB20, RB, 4G63, EJ20 etc engines.
I have 3x FD ECUs here which have aftermarket chips in them which I'm willing to play with a bit more also

 

matt rc, do you have an eprom reader? or can you borrow one?
I'm going to say it. if you don't want to contribute, shut the hell up! your guys are as bad as prolife activists.
It isn't going to hurt you, back off.

 

I apologize greatly for not taking much time with this as of late. I'm right in the middle of Physical Therapy for my damaged shoulder, in preparation for surgery. I've been thinking and tinkering constantly, looking at some older rom dumps that i have of some other performance chips. I've also been trying to adapt some Rom editing software to suit out needs. I will get back to this, I'm just working a bit slowly, as the therapy kinda wears you out and amplifies what pain was already there. I have not forgotten.
Go get em' Tweaked!!!!!!

 

I finally got a spare ECU. I should be cracking it open in the next week.

 

jinx22630, I do not know a lot but I am willing to help in any way. I was wanting do the same thing bt just do not know enough to do it(but maybe after majoring in electrical and mechanical engineering after High School).

 

Odds are you're not going to learn anything that would help you out with that in EE and probably hardly any at all in ME. You'd honestly probably be better off just leraning it on the forum. I too would be interested in if there was some way to come up with an informal write up on how to read the code and work on it myself. I am really interested in how these things are written.

 

It depends on what he wants to do within EE. If here wants to do microcontrollers/embedded systems, he
could learn a lot.


I've cracked open my spare ECU and checked the ROM number against those listed at:
http://www.16paws.com/ECU/bin-images/Rx7-ecu.lst

I have 277 and 287 ROMs in my spare ECU. Hopefully they are the same as the ECU that is actually in my car, but that link lists the ROMs for an '86 GXL as 275 and 285.

The part number on the cover on this ECU is N326 12 881C. Since the part numbers are the same for ECU with several different ROM versions, I'm going to take a SWAG and assume the there were a few bug fixes made. This would result in ECUs out there having different ROM #'s but not different part #'s (they would want any ECUs replaced to get the newest code). Included in this guess will be the assumption that higher number = more recent (bugfixed) version. This means I'll want to do my work on the 277 and 287 ROMs.

I've ordered this:
http://www.batronix.com/electronic/c...eprommer.shtml
programmer.

Next I need to order a couple of ZIF sockets for the ROM ICs (28 pin DIP package) and a bunch of blank EEPROMs.

 

What's your level of knowledge?

Do you know how to write computer programs? In assembly language?

Do you understand basic electrical principles? (Voltage, current, etc)

 

Datasheet for 2764 8kx8 eprom found.

http://www.microchip.com/1010/pline/...vices/27c6412/

 

Digikey part #s for low profile ZIF socket and UV-erasable EPROM.

497-1684-5-ND IC 64KBIT UV EPROM 100NS 28-FDIP $4.86000
A346-ND SOCKET 24PIN ZIF LO PROFILE $6.03

 

If anyone technically inclined can read Japanese, I would appreciate if they would take a look at this site:
http://www.romtune.com/

Babelfish gives me stuff like this:
"Simply, in the throttle position sensor, those which become the idle switch existence
Because it does not do, it detects idling in some wind, details are unclear."

which makes my head hurt.
(I wonder what Noam Chomsky would have to say about that sentence.....)

 

EE would not be completely useless, but I'm saying that this is more of an applied EE thing. I'd imagine it would make learning a much faster process but my point was more that you're not going to learn all about how the ecu works in EE 3xx or 4xx.

 

Actually, EE476 at Cornell is all about microcontrollers. They don't talk about ECUs specfically, but it covers that type of system: small computer, little RAM, programmed in C or assembly, responses to sensors are time-critical, etc.

So you're right that there's no courses specfically on ECUs, but you are going to learn all about how a system like that works.

The forum is good for learning about the engine that the ECU is hooked up to and for answering things like "What's the best why to tune spark advance?", but he's not going to find a good explanation of how a microprocessor works and what an EPROM is.

 

Just out of curiosity, do you guys have any idea what type of processor is in the ECU? I have programmed microcontrollers, and just looking at a pile of bits in a rom without knowing what hardware is processing those bits doesn't seem very promising. For example, the processor may not even be a general purpose off the shelf item. If it were, the data in the rom would just be a program that you might have some hope of decoding if you knew which processor you were dealing with. If the processor is a custom unit, the data in the rom might just be tables of information that could be very difficult to interpret. What plan do you have for testing your ideas? If its just changing data in the rom and seeing what happens, I think you have a long road ahead of you. If you had diagnostic hardware to log the inputs and outputs of an unkown processor you might stand a better chance.

 

Someone else has already established the processor to be a Hitachi 6303.

 

I know a little c/c++, pascal, basic, html, scheme nothing hardcore. I have been trying to learn x86 assembly
http://webster.cs.ucr.edu/AoA.html but school keep stop me(homework).

I understand basic electrical principles and what the components do. I just do not know how to use them to perform a task or job(like making a radio or something).

 

Yeah, and he's an engineer Interesting thread, I'm all for innovation

 

Sounds good.

The first thing you can do is familiarize yourself with this:
http://www.16paws.com/ECU/chips/HD6303.pdf

(I figure nows a good time to mention that I plan to GPL any code I generate during this project.)

Once my programmer comes in I'm going to read out the contents on my EPROMs and compare them to the images posted on that site. Then I'll start trying to disassemble the code.

I may also add a serial port for degubbing purposes. If I do, I'll post a schematics so people can duplicate it.

 

No problem, I found that site about a 6 month ago when I was doing a little research on the rx7 ECU. I have read most of it and did not understand some of the things they were talk about but maybe I should read it again. I have no problem with GPL issue. Free software is great

 

By the way, I'm still working on this!!!!! My PC that I had everything stored on, turned cannibal and ate itself.
So I'm having to start over again trying to comment out the Rom dissasembly. Makng progress though, I'm using IDA PRO to do the 8086 stuff. Its pretty cool, anyone interested should check it out.

 

Guys! You're doing a GREAT job! KEEP IT UP! I think all of us should pray for you!!!

I wonder why nobody really tried (and finished) a project like that taking in count that it is a 15-years old car... Sounds strange, isn't it?

And one more time thank you for your efforts!

 

jinx i also applaud for even the attempt to make a contribution for free to the rx7 community. the negative feedback here disgusts me.. hes doing something FREE that will help.. not a 700$ ECU.. ITS FREE.. and you take it and get it tuned JUST LIKE A HALTECH.. omg people how can you give any negative feedback. let the man do his thing and all of us without $500++++ to spend on a ECU can be happy

 

Which ROMs are you working on? (chip numbers)