Wanted Non-functional, broken, dead KZJ78 ECU for reverse-engineering/possible alternatives (1 Viewer)

[Tigris]

Location

United States

Hi,

Many of you know that the KZJ78 ECU is a sore topic. These ECUs (AT version) are plagued with the leaky capacitors of the 1990s that caused great many of them to self destruct.

Being an obscure, JDM only offering, the KZJ78 ECU is now unobtainium. And if you would find a used working unit it would not be cheap. This has led meny to go the full mechanical route, which has it's pros and cons, of course.

I want to experiment with the possibility of hot-wire dumping the EPROM of a dead unit and then flashing it into some other, cheap and reliable ECU, matching the pinout. As far as I can tell this has never been done, yet.

I would be interested in any donations or reasonable prices for dead ECUs.

Let's make this happen!

Cheers!

 

[PAToyota]

I don't have any need for a KZJ78 ECU, but commend you for taking on the challenge!

 

[Tigris]

@PAToyota
I appreciate that. Yeah ever since I had to fix my own KZ ECU (which luckily was repairable), I've been thinking of a more reliable solution for myself down the road and the rest of the community, knowing that the electrolytic capacitors sourced by Denso at that period were simply just little time bombs ticking away lol.

I have some experience dumping EPROM via hot-wire or similar non-standard means, but never on a circa 1990s ECU. So I guess we'll see!

Cheers

 

[OGBeno]

@Engineer8000

 

[Engineer8000]

I assume the KZJ78 ECU uses a propriatary denso processor?

 

[Engineer8000]

I have some info on the fj62 ECU processor and it's instruction set, obtained from the Supra guys.

 

[Tigris]

Hi,
I believe they do, judging by the chips' designation from what I recall.

 

[Engineer8000]

I guess you could write some code to emulate the denso processor, above my head.

 

[Tigris]

I have some info on the fj62 ECU processor and it's instruction set, obtained from the Supra guys.

That could be very helpful as there might be some commonality between the 62 and 78 Denso ICs. I am still in the approach formulating phase. I was contemplating identifying the EPROM IC pinout, supplying slightly lower power in situ, and dumping it with an Arduino and a breadboard.
Of course, this approach is not guaranteed to work, but it's worth spending a few hours playing with. I have used similar techniques to dump and spoof immobilizer chips and similar copy protection circuitry before.

 

[Tigris]

I guess you could write some code to emulate the denso processor, above my head.

Actually I would try to avoid resorting to that as although it's doable, it is very tedious. I am hoping that once I get the hex dump, I can flash it into a slightly newer 3 plug cheap Japanese ECU (Think: Late 90s AT Corolla, Crown, or Camry) and match the 3 plus' pinout as necessary.

These ECUs can be had for $15 or so and share a great deal of commonality with the KZJ78 from my research.

 

[Tigris]

Of course, having the hex on hand could (with the help of a decoder on a PC) open the door for potential on-chip tuning, or, if the host EPROM size allow, selectable presets prior to flash. That would certainly be a neat thing to bring to these old diesels!

 

[Engineer8000]

So the code is stored on an eprom in those ECUs? Is it encrypted?

 

[Tigris]

The parameters are stored in an EPROM IC. That much I figured out though the chip ID. But I do not know if they're encrypted or not. I would wager that they are not judging by the era's practices but I don't know.

I know that the immobilizer ICs I encountered were unencrypted, and that would be the more likely place for the OE to encrypt.

Nowadays encryption is easy and cheap, but back then it was a costly feature to implement. Every encryption needs a decrypter onboard.

 

[Tigris]

I am currently deployed overseas and should be back in March so I have time to research this further. I have a fellow Mudder sending me a KZJ78 ECU for a recap when I get back. I am not charging for the job but I also can't use his ECU, or my working ECU for that matter, as a guinea since I run the risk of erasing the code or frying something, hence the need for a non functioning unit and the reduced supplied power to keep this readable yet calm.

We'll see. Thank you for your insights!

 

[bottombracket]

@Tigris you may want to reach out to Mick Wallin on Facebook or via his website 1hdfte .com.au

Mick builds stand-alone engine harnesses for 1HDFTE and 15BFTE, and I know he has done stuff with the 1KZTE. He’s working on a stand-alone ECU for FTEs.

Mention my name (Galen); he knows me. Feel feee to PM me here with any other questions.

 

[Tigris]

Bump

 

[Tigris]

Wondering if there were any available