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ROM reprogramming


Fanta
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You know - has there ever really been any attempt at taking a ROM chip and changing some diameters and putting in in place of the stock one in the stock ECUs?

 

And yes, I'm well aware that nobody has ever decoded our ECU coding. Just musing over the thought ( and also somewhat amused that a tuning method used since the 80s has been more or less skipped in this car group and we went from piggybacks to stand alones lol )

Edited by Fanta
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A few people have played with the standard ECU in Australia. A friend use to run a modifed ECU in his car before going to MPI, As far as i know it just had the boost cut eliminated and better mapping for higher boost.

 

Someone also copied a ROM from Fueltronics and burnt some more that were solderd onto the factory board. Not sure what changes it made but apparantly you had to run Premium gas in it all the time. There was a thread on Austarion about it.

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i did some searching a few years back but came up empty on another chip to replace the stock unit. I had a paper copy of the hex dump file. I know a guy that works with hex dump stuff on other cars and he puts it into excel and does plots of the data. since ours only controls fuel it should be fairly simple. I couldnt find a socket but i didnt really spend too much time messing around with it before i dropped the change on a megasquirt. If someone has a digital copy of a hex dump file from any years i can give it to my friend and see what he can do to decode it.
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just for starters the chip is solder'd in , you have no serial port info from the ecu, and no way to make changes on the fly

 

Well - I was reading an article and some tuning shops unsolder them etc

 

Thinking about it - Starion76's roommate would program ROM chips for arcade terminals they had in their house off a pc.

 

And its not trying to make 486 out of 286 - but it couldn't hurt to look at a method of programming the ECU's instead of using piggyback for those who aren't going standalone.

 

Plus if anything - it opens up a new option of tuning our cars ( since piggybacks sometimes aren't the most accurate depending on what you use )

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Just go MPI.

 

http://failblog.files.wordpress.com/2008/04/woodenjack.jpg

 

What are you planning? Remapping to enrich the mixture? then you still have bad fuel distribution because of the wet manifold.

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just for starters the chip is solder'd in , you have no serial port info from the ecu, and no way to make changes on the fly

 

 

your best bet is to remove the chip and solder in a connector so you can have a remote mounted chip on a piggy back board. or just a connector so you can run the hex dump off a laptop. The way it works is actually really simple. If you look at it as if it were a graph it just takes the parameters input and references a point. Once decoded im sure it would be very easy to work with but the problem is finding a chip. The chips were mitsu pieces and i wasnt able to find any cross reference on them. its also not out of the question to convert the stock ecu over to driving 4 injectors(pre 87 style) but it would be batch fire and no info i have found links the injector pulse with any sort or timing to the piston position. I lost my picture archive but i can crack an ecu open of you want the chip numbers. i remember is started with MD :)

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Just go MPI.

 

http://failblog.files.wordpress.com/2008/04/woodenjack.jpg

 

What are you planning? Remapping to enrich the mixture? then you still have bad fuel distribution because of the wet manifold.

 

the whole point of me wanting to know about the ROM programming is to accurately tune a TBI car

 

piggy backboards - hmm - the 88/89 do have daughter boards.

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For the time and money invested as well as the posiblity to realy screw your ECU while desodering the chip. I have to ask WHY? For the price run megasquirt if your looking to tune it. We know more about it and it's got way more options. Since it's fule only you could run megasquirt 1 im sure you can Ebay one for 50-70 bucks. For blanks and someone's time with the chip reader your going to spend 40 bucks.
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For the time and money invested as well as the posiblity to realy screw your ECU while desodering the chip. I have to ask WHY? For the price run megasquirt if your looking to tune it. We know more about it and it's got way more options. Since it's fule only you could run megasquirt 1 im sure you can Ebay one for 50-70 bucks. For blanks and someone's time with the chip reader your going to spend 40 bucks.

 

87 ecu's are plentiful enough...

 

why? I find both amusing and sad that compared to every other car affeciando group, even from the 80s - have their ECU's decoded yet we don't?

 

Also - what if someone doesn't want to bother doing a harness and such?

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Most of the other's you are refering too were based off of something else in that line for the later models and the early models were very simplistic. They also have a much larger following and user base. There components are still avalable. Chances are Mitsu made the chip just for this ECU.

 

As for the harnes just buy one then. Got mine for 45 bucks I think.

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  • 8 months later...
I pondered with this idea quite a bit. I expect that the ROM could be dumped, but to do any changes you would have to solder in a chip that overrides quite a bit of lines. It sure would be interesting though.

 

I need to bring myself back up to speed with what people with the FC's and other cars of the 80s do - but you're pretty close.

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I'm all for this. According to the link you posted the chip is a 27C512. That is the same chip my 89 2.2 Chrysler uses in it's computer. It is a 27SF512 right now which is re-flashable. I had the ECU board socketed so the chip can be removed. I can make change to my fuel, timing and various other things using programing from DCAL and Mopar Chem. I don't see why this technology can't be applied to the mitsu ECU. I am still learning and a novice but there are others that have added to the factory code to do some amazing things. I don't think that a MPI conversion with the factory ECU would be out of the question either. Check this link out to see what can be done,

http://www.turbo-mopar.com/forums/showthread.php?t=22703

 

Bob

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The problem is... our hold up isnt the ECU at all... Over 300 at the crank is as easy and safe as turbo, fuel pump, header, cam and turbo. Youll get no more out of our cars with a reprogrammed chip as the 2 injectors and the crappy intake are generally going to be a little rich all the time for safetys sake. Then your back in the game of using more air and timing to scavenge that fuel into usefulness, which is exactly what your trying to do with a reflash anyhow.
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  • 4 weeks later...

Technosquare does this, and has been doing the ecu for quite a while. They are the USA distributor for Techtom, which has been making Japanese ecu tuning tools and hardware for a long time.

 

http://i219.photobucket.com/albums/cc103/vprtech/technosquarestarion.gif

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Technosquare does this, and has been doing the ecu for quite a while. They are the USA distributor for Techtom, which has been making Japanese ecu tuning tools and hardware for a long time.

 

http://i219.photobucket.com/albums/cc103/vprtech/technosquarestarion.gif

 

HHHHHHHHHHHHHHHMMMMMMMMMMMMMM!!!!!!!!!

 

I am very interested in this.

 

Technosquare is in Torrence which is a suburb of LA. I may be in the LA Area in late Fall this year.

 

From your above link Starion 1988-1989 G54BT FUEL A175BTR64 $295 for reprograming the fuel maps.

 

According their website some of these guys are the MITSU ECU guru's from Japan.

 

Hell, I'm going to call them tomorrow and look into this.

 

For What It's Worth.

 

KEN

 

Chris - one HUGE ATTABOY :ylsuper: :thumbsup: if this is something doeable and it meets the needs of the Starquest community.

Edited by Starfighterpilot
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