WTB: "TMS15-NA" TechTom daugherboard (S15 N/A)

[CoZZm0]

hi all, hope this is OK to post (I still have my Nistune, but this is for an application Nistune doesn't supprt).

I'm looking for a fairly uncommon EPROM based board which was used for the S15 N/A ECU made by TechTom as far as i understand. The board i'm after is pictured in the attachment. I don't care what tune is on it or what ECU its in, i'm really only interested in the daughterboard itself. If you have one, or know someone that does, please let me know. cheers.

[Matt]

Try from GRID since those boards are used in the SR16VE/SR20VE ECUs also or also NZ EFI was where I got mine, for reverse engineering (not for sale) but haven't got around to it. We use S14 SR20DE ECUs with Type 5 board for these vehicles (few wiring swaps required)

[CoZZm0]

My application is for the SR20VE in this case. I’ve asked a few of the NZ guys and they only have the KBM50AA boards as that is what they mainly use. Thanks Matt.

[Matt]

KBM50AA is the equivalent (non techtom) from what I can work out 2 x 40 pin + 1 x 4 pin connector so should fit

[CoZZm0]

It does fit but there is a persistent knock sensor code 34 which is a known 'feature' of using that board. I actually have 2 of them sitting here but have held off fitting one at this point because the last time i plugged an ECU in with a board fitted the CVT did weird things and went into a 'limp' mode and i'm not sure if its related to the code 34 from the ECU. While i'm experienced at soldering, i don't enjoy desoldering 85 fine pitch joints, i'm sure you can relate.

Part of the issue i'm having is knock so i want to retain the factory knock control. I have done significant mechanical inspections and repairs to various parts of the engine/system to ensure its all up to scratch before i try and tune around it, however it is a 'known'/common issue with these cars when using the CVT transmission which regularly loads the car up below 2000rpm and down as low as 1300rpm on acceleration until you 'squeeze' it for it to vary the ratio to allow better acceleration.

Convert it to manual like everyone else does and there's no issue because people don't drive/accelerate below 2000rpm in a manual regularly.

I'll probably just end up using the KBM50AA board i have here as i'm getting varied information about whether the TMS15-NA board will throw a knock code or not.

[Matt]

Is the same issue as the board we used to base our Type 5 board from. They have a knock sensor fault code, so it needs to be disabled
http://nistune.com/docs/KnockGuideSR20.pdf

There must be something in the logic which is not getting passed through properly for the knock, and causes the problem, since the board has to mutliplex passing through passing through signals (switches like TPS idle, neutral etc) to the 'input port' on the ECU microcontroller as well as also using the same port lines for buffering and handling normal memory address accessing to the EPROM/NVRAM

Obviously techtom have figured out with their board, but their stuff is locked down tight which is why their stuff has not been reverse engineered

[CoZZm0]

Interesting to know it’s the same issue you face with other hardware. Thanks for that explanation Matt.

I have gone ahead and installed the fresh KBM50AA board I have today and the CVT seems to be behaving on the first drive so I’ll monitor it over the next week and make sure ‘all is well’ and move on from there. For now I have just done knock copy from the primary maps but looking at your guide I need to change the feedback flag too. Some of the other tables mentioned haven’t been identified in the ROM I have but I’ll look at the address files and see if anything else lines up. Great info, thank you.

The first ECU I tried, the soldering for the board was terrible and I think that was the issue all along. I am a lot more fussy so this install worked first go which I was happy with.

Thanks again for the info.

[CoZZm0]

Im sure you have the scrambler and descrambler info for the TechTom stuff? Given they use two very large CPLD instead of just the one small one that does increase the complexity for you.

[CoZZm0]

One last question, have you ever seen a board that looks like this (attached) for similar model ECUs.

I missed out on buying this ECU by about 10 minutes and its bugged me ever since as i've never, ever seen another board like it installed in any of the ECUs i've researched. Its an JN15 SR16VE N1 ECU (hence the 8 injector drivers). Seller could provide no information about it other than it came from a car and couldn't/wouldn't pass my contact details to the buyer so i could get more information, which i understand.

[Matt]

Im sure you have the scrambler and descrambler info for the TechTom stuff? Given they use two very large CPLD instead of just the one small one that does increase the complexity for you.

The CPLD will be 'lock read' so you cannot read those out, only put a logic analyser on the input and output lines. I don't even know the 2 x 40 pin pinouts for these to get started. One would assume maybe the 4 other lines are R/W, E logic

That picture one is very interesting, and gives a hint how it may work. It is using two 16 bit ROM chips, maybe one for each of the 40 pin connectors. It could explain maybe there is one CPLD for each ROM (but the CPLDs on your ECU are different amount of pins, so different type of CPLD)

There is epoxy over all the drivers and caps in that image, but no idea why

Looking at the silkscreen on the rear, appears the board could be an official JECS board. Wonder if there is also CPLDs on the other side. Yeah pity you couldn't get hold of that one

[CoZZm0]

Thanks Matt, i was referring to the often scrambelled ROM images of the chips on the techtom boards as opposed to the CPLD program.

Yeh i imagine the epoxy is because it was a 'race' ECU and they did that to ensure things didn't vibrate and break or something. i'll keep looking for it, but i wont be holding my breath.

[Matt]

scrambelled ROM images of the chips on the techtom boards

Some boards scramble ROM chips (JWT) but others like techtom for normal tuners are normally straight through (like the R33 boards) so the ROM contents might not be scrambled. When you read the ROM images, how did they look?

Usually with these boards I see only a couple of address lines scrambled, but really need to pull each address line up at a time (simulated ECU) and check the address lines on the chip to work how it is scrambled

[CoZZm0]

No problem, i found some info, related to some toyota stuff mostly but wasn't sure if it applied to nissan stuff as well. All good.

[CoZZm0]

Just wanted to double triple check that yours is not for sale Matt ? (yes i'm tragic and still looking for this crap..).

I emailed TechTom and they advised they sold their ROM board IP off years ago, they have no old stock and the company that bought the IP is no longer contactable despite their own best efforts. Also contacted the USA TechTom agent who used to sell the stuff and he doesn't do any of that kind of thing anymore. My own efforts to find one have proven unsuccessful despite finding the odd one for sale but already sold.

[Matt]

Sorry it is not. It's waiting for a rainy day to fully reverse engineer it.

Your best bet would be to find a chipped SR20VE ECU with it already. However that would be quite difficult also