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Hi, i'm Dennis i'm from the netherlands and i recently modified my '93 Mitsubishi galant 2.0 V6. I swapped my engine for a 6a12tt VR-4 engine.
I also swapped the 4wd, i took a lot of scary nights because i had to cut out and weld back a big part of the bottom of the the car to get in the drive shaft and rear diff, but it went fine.
I was wondering if my Ecu is flashable, i'm all new at this so i'm very curious!

The MD number of my Ecu is MD180563, E2T38875 M, 3726, 007.

The number on the CPU is M37793E4TW, A238 3704, E092.

I hope somebody can tell me more about this, if more info is required, just ask!

Thnx and Grtz Malfie

The M3779x MCUs aren't flashable. Sorry

Gatecrasher wrote:The M3779x MCUs aren't flashable. Sorry

Hi, do you have any information about this MCU? Is it 8, 16bit, kind of 68HC12 or something different?

Here is a summary of what I know about the Mitsubishi/Renesas 7790 series MCUs

16-bit MCU, which can be switched in software to operate in 8-bit mode
84-pin PLCC package
103 instructions
Mask ROM or one time programmable EPROM.
A cousin of the 68HC11 architecture, but with many differences.

Used in various Mitsubishi Electric Automotive ECUs, as well as multiple JECS (Nissan, Subaru) ECUs.

Only sold to Japanese manufacturers. Possibly only MEA and JECS.

The only datasheet I've been able to find was posted by Calum Johnson of Calumsult. This was a 6-page partial datasheet for a 7790 MCU. He also has a pinout only for a 7791. Documentation is pretty much non-existant, and must be derived from other Mitsu/Renesas 7700 series MCUs. There are a lot of hardware differences, so this is not easy. Fortunately, the 7700 series software manual IS available. This has been invaluable in my dissection of this MCU.

My experience is with the 7793 and 7798 as used in the Mitsubishi 3000GT and Dodge Stealth. Specifically:

M37793E4TJ and M37793M4TJ. 2K RAM, 32K ROM. E in suffix = EPROM version and M = Mask ROM.

M37798E7TJ and M37798M7TJ. Unknown RAM (2K?) and 48K ROM.

The only way to enable reprogramming is by installing something like a Techtom daughtercard.



Unfortunately, this disables multiple functions on the MCU, as the pins are reassigned to communications with the external EPROMs. Those functions must be recreated via a device such as an FPGA. This is no trivial task.

I owe a LOT to Calum Johnson. His notes and explanations have provided invaluable help in this project.

This might be out of the topic subject, but instead of using the un-flashable M3779x MCUs, is it possible to flash an ECU off an EVO5/6/7/8 to run on this engine? (or other modifications/chipping). I found some fair priced EVO8 ECU on ebay and it will be nice if they can run with the 6A12 engine.

I noticed the major difference is that one is 4 I-cylinders and the other is 6 V-cylinders, so I am wondering if flashing the ECU can actually alter the pin-out.

Sorry if my question sound silly, but it was never clear to me what type of information the EPROM stores and if it's possible to change 4I to V6. I read a document on someone completely rewired an OBD1 car with OBD2, so I am sure it can be done, but there seems to be limited flashable OBD2 ECU with 6 cylinders.
Any suggestions?