TonyB_GT4 wrote:If I read this right, you can not reprogram your ECU, so you are going to design and build your own?
You are either very clever (with too much time on your hands) or extremely brave
Maybe I'm just a little mad
TonyB_GT4 wrote:With the amount of time, money, and R&D, that go into aftermarket ECU's, how come you are not considering buying one? (Sub 1k) I would have thought that it would make economic sence? Or are you just after a challange?
To be honest there aren't any aftermarket ECUs that suit my appllication. I drive a Toyota Soarer which uses a Karmen Vortex AFM which does not present the same kind of signals you would get from a hot wire device or map system. Also the ECU controls the gearbox so a straight aftermarket device just isn't available. I specifically want to re-map both the inection and ignition system as well as altering such items as rev limiter and top speed limiter ( jap import so 180kph max). The gearbox control features 2x patterns (econ & Power) but they aren't very different. This offers me the opportunity to program a far more agressive gearbox map for the power setting suitable for track or fast road use
ScoobieWRX wrote:
I applaud you for what you want to do, but i have to say as an ex-electronics development engineer it's no mean feat, even with schematics not only of the board but for each of the microcontrollers you're going to transplant.
You have to know what each leg of the controller does, i.e. input or output, what each of the functions are and which through hole on the board, where the controller is going to sit, is each of the legs connected to, unless you have absolutely full step by step instructions or have bought a ready to assemble/solder ECU kit.
Equally you can get converters/adapters for your controllers that fit onto where the old controllers went and you place your new controller on that, then program it but even so the adapter has to be board/controller specific. Otherwise i see a lot of soldered wires coming off each of the controllers legs to different components on the board, and that may get messy.
I can see wher you are going with this and perhaps I didn't make the plan very clear (I would agree that replaceing the controllers would be a nightmare). Remember that these controllers are hardly what you would call 'state of the art' more 'state of the Ark'. The particular controller I'm using has 2x main boards the one in the picture is the digital board which contains no less than 3x CPUs which I believe are 8500 based controllers - but as they are Denso marked chips, no-one is quite sure whcih variant. The other is the Analogue board which contains such things as the relevant driver circuits for Inector drive, Ignition coil drive, Baromertic equilisation, filters and interface circuits etc. This is not al that technical and can be plotted out without too much difficulty.
The conventional way of altering these ECUs (such as TomTech) is to unsolder the processor and remount it on a separate daughter board. It is not too difficult to dump out the Rom code (internal and unalterable) to an external EEPROM, and then get the chip to use the external data. The downside is that many of the original pins are used as I/O for measurement etc, which become address and data pins once set to external memeory mode. Thus you must either find a way of replacing this lost functionality or simply replace the dynamic readings with static date in the ROM chip at the appropriate memeory location.
My solution is to fully map and understand the operation of the Analogue board whcih will be retained. The Digital board will be replaced completely with a new unit, designed to interface correctly to the existing analogue board. The new digital board will run completely new code but designed to match the original functionality as closely as possible, but with the additional features I require. Given that the new processors I am using are many times faster than the originals, I'm not too concerned if my code is not as tightly integrated or as optimised as the original. Using the chips I currently have on hand gives me 16/32 bit capability with 40MIPS.
Using this method, I can incorporate any new features I want such as the different petrol & LPG maps, different gear maps and loads of realtime data logging.
If there was an easy and reliable way of doing this I'd probably take it. As it is the only available options are the likes of TomTech at about
Of all the things I've lost......
I miss my mind the most.
If at first youu don't succeed .................... Skydiving is NOT for you!
