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Thread: Funny adventures in electrical engineering

  1. #101
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    Not a bad idea, however I'd need a 7m-gte pcm to extract the data from. There IS a file already posted on the net (courtesy of supramania forums) but I didnt see a schematic... without the schematic I cant track back from the injector drives to the code that calculates injector timing... I could assume, but I think it would be messy in the end and nothing would come of it without the PCM in hand or a good schematic.

    That PCM also uses a different chip, same as the 1UZ and likely later 4a's, so I'd like to get this bluetop stuff off my plate before changing around my setup for something else... actually I'd love to sell a prototype run of bluetop boards to recover my investment in dev tools, but I wont be advertising those until I can offer some real tuning options (however complicated) and have tested my dev PCM on someones actual car.

  2. #102
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    Sooooooo, some people may remember the thread about the 20V ignition multiplexer and stuff, and part of that was to be a tach emulator. Prodah-G loaned me a GTS gauge cluster and I started work on the tach drive emulator, blew up my development processor and then got pissed with the process. That's on hold right now because I like hopping from project to project and seeing immediate results, so I did this:

    Donated from a crashed SC400 in salt lake city, UT (along with harness, ignitors and AFM! about 100$ all in! Utah is americas wrecking yard, I swear)


    Peeking under her skirt, apparently some chips are now missing? were those the microprocessors with tasty toyota secrets hidden inside?


    Oh there those chips are!



    So code from both micros has been pulled from the chips and pushed onto git, along with preliminary disassemblies. This micro has a LOT less documentation than the last, so it will take longer to reverse engineer, but rest assured 9000RPM is simply a matter of diligent effort now, and not just a pipe dream.

  3. #103
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    1UZ update: slowly disassembling away.. this PCM is far more complicated, and far less documented on the micrprocessor side, so results do not manifest as quickly. I seem to be spending a lot of time simply re-hashing toyotas code on the bench trying to see what it is doing to the micro. rest assured that it IS coming along though. anyone who wants to pitch in can download IDA 4.9 (free!) and check in at github where all the resources are ready to go
    https://github.com/sparkiedk/Toyota-PCM-hacking

    4A-GE bluetop questions: while the spark tuning can be accomplished by hacking at that 3d table, the fuel algorithm is basically pulsewidth=(magicalconstantssupermath)*AFM_angle. this doesnt leave much in the way of specific cell tuning, though gains can be had on modified motors by simply increasing/removing the AFM angle limiter in the code (it's a lookup table). What i was thinking of adding was an Alpha-N (*shame*) post-calculation tuning table, and I wanted some opinions:
    is 8x8 enough? the way the RPM value is stored doesnt lend itself to 16 level RPM resolution nearly as well as 8 level.
    do you want additive/subtractive pulsewidth (if so - how much? what resolution? if 100us a bit is okay it's dirt simple to get ? 12.7 ms of tuning)
    or do you want ratiometric tuning, as in a multiplication of the calculation output against a 0.xx to 1.xx number?

    keep in mind I could add ALL OF THE ABOVE, and make it sing and dance and play trombone, but it's not a fast microprocessor. table lookups require interpolation (3d table lookups require three interpolations!) and multiplication is slow, like 7us slow. More importantly I've never tuned an alpha-N car before, what is it like? is 16x16 or higher required to get a good tune, or would 8x8 work well enough (especially as it's sort of riding piggyback to the factory ecu) to get some good tuning done?

  4. #104
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    I would definitely get on top of this, but the best I can do is program an arduino. The first time someone showed me how to even program a simple PIC... I just smiled and nodded and took in only half of what was laid down. Knew I should have taken electrical instead of mechanical.

  5. #105
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    Just re read this whole thing. I'll do it one more time and hopefully have it all figured out

    Just wanted to say thanks and keep up the good work. Pretty excited about what you're doing here!!
    Mat 83 GTS Hatch 87 GTSR5 Coupe
    Quote Originally Posted by KingSpence View Post
    If only I put the same amount of effort into my schooling as I do my car. Education is important, but racecar is importanter.
    Stuff I'm Selling
    IG Mattyballz86

  6. #106
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    Thanks for the encouragement. I just found the rev limiter in the 1uz code (6602 RPM for this particular SC400 PCM) so the science is definitly still plodding along. not too much work is getting done to the bluetop PCM because I dont have a test mule to validate my work so I can go ahead with board manufacture.

    ...that and the 1UZ is more exciting anyways.

  7. #107
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    If I had a 16V I'd let you tinker with it.

    I wanna do a 16V swap at some point for my SR5

  8. #108
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    I have a couple ecu's collecting dust somewhere lol

    Currently running a 16v bluetop with exten$ive work done and would love to increase teh rev limiter on this b**ch.

    Car is stored till spring

  9. #109
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    ..that and the 1UZ is more exciting anyways.
    Much more exciting. Get er' figured!

    Also, where do you buy this stuff out of Utah from?
    1JZ 1984 Celica GTS
    1UZ 1981 Corolla sedan
    ? 1972 Celica race car

  10. #110
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    Quote Originally Posted by Prodah-G View Post
    I have a couple ecu's collecting dust somewhere lol

    Currently running a 16v bluetop with exten$ive work done and would love to increase teh rev limiter on this b**ch.

    Car is stored till spring
    Aye, this IS the problem. Mr. E has also been a supporter (albeit forum quiet) of rad bluetop science, but alas his ride is also napping while the salt flies.

    extensive work eh? cams, with cam advance? because then I'd love to see if you're running into the load limiter at high RPM. a table controls the total load value (read: AFM angle) and it increases for a few thousand RPM before levelling out, meaning that your ALLOWED torque drops with RPM, much like the factory torque curve. this can be removed to allow the PCM to hose the motor down with the fuel it deserves. you'ld know it's happening for sure if when you lift throttle a bit it gets faster at high engine speed (oxy sensor corrects lean condition when not WOT)

    Ken, you got a running 16V that can be used for testing right now? or is the engine on a stand somewhere?

    Quote Originally Posted by clay72 View Post
    Much more exciting. Get er' figured!

    Also, where do you buy this stuff out of Utah from?
    there's a u pull it yard call Tear-A-Part in salt lake city, i go to SLC occasionally for work, so I always make sure to take a stroll through the yard. there's a 2$ admission fee but it's usually worth it. I buy a walmart tool kit and return it when im done, costs about a buck in currency exchange on my credit card and it's totally worth it to have the right tools on hand.
    Last edited by Sparkie; 01-31-2014 at 08:29 AM.

  11. #111
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    Stock cams and springs right now due to budget restraints on the last round, but it's on the short list along with a small turbo....

  12. #112
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    Update: ever wanted to know what the 1uz injector net dead time works out to? here yah go!
    Click image for larger version. 

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    and the factory table it is generated from:
    Code:
     5.9608  2512
     8.0000  1568
    10.0392  1024
    12.0000   800
    14.0392   544
    16.0000   432
    Happy megasquirtin!

  13. #113
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    And because I love yah guys so much, base timing 3d map, unscaled and somewhat confusing, the only thing that IS scaled correctly is the timing values.

    I gotta deal with some offsets and load isnt really a sensible number anyways, but here's a start. infer what you will about our precious V8
    Click image for larger version. 

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    Click image for larger version. 

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    and the same surface as the above (yah, theyre the same) in an isometric view.
    Click image for larger version. 

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  14. #114
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    Wow. Just read through this entire thread.

    This is awesome! History being made here at DK!

    Keep up the great work!

    EDIT: Wow, haven't posted here in a long while. LoL
    Last edited by The VidKid; 02-13-2014 at 11:35 AM.
    - TVK -

    "There's A Vid In All Of Us!"
    "Do You Know How I Fix Rusty Cars? I Buy A New One." - Ben (Soulibrium)

  15. #115
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    thanks for the feedback!

    you good at programming at all? still looking for volunteers to get some source diving done.

  16. #116
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    Quote Originally Posted by Sparkie View Post
    thanks for the feedback!

    you good at programming at all? still looking for volunteers to get some source diving done.
    I'm pretty well versed in several computer programming languages (Well, used to. It's been a few years since I coded anything useful), but nothing involving electrical circuitry at this level. I don't think I would be much help. LoL.

    I've dabbled in Assembly and it's not an easy language to learn. Isn't it like 1 or 2 levels above binary? I'm very impressed you're able to read, code, and debug with it.
    - TVK -

    "There's A Vid In All Of Us!"
    "Do You Know How I Fix Rusty Cars? I Buy A New One." - Ben (Soulibrium)

  17. #117
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    Assembly is about a step or two above 1's and 0's, all assemblers now (and for like the last 30 years) will be intelligent about names and addresses, so it's not as if you have to manually punch in addresses for all your variables - simply name a place of ram and it will be that name subsequently. as for the machine itself, it's rather simple: this processor has 3 16 bit registers the code farts with regularly: X, Y and D. D can be accessed as 8 bit registers A and B (D=A:B). anything you do will consist of loading, storing or mathing on these registers. there's also a 16b stack pointer and a 16b instruction pointer which behave in the expected manner. add to the mix special function registers (with homebrew documentation) and 700 bytes of RAM and 16k of ROM and you have a fuel injection computer!

    the 4a-ge computer is a real gem, it only has accumulators X and D (A:B) and 192 bytes of RAM, and 4k of ROM, and it can't divide (they use a table, creatively).

  18. #118
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    Interesting. Very interesting.
    - TVK -

    "There's A Vid In All Of Us!"
    "Do You Know How I Fix Rusty Cars? I Buy A New One." - Ben (Soulibrium)

  19. #119
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    1987 Corolla GTS Hatch | 1985 Corolla GTS Coupe | 1987 Corolla GTS Coupe | 1992 Tercel CE | 1992 Paseo | 2003 Corolla CE | 1974 Corolla 4 Door | 1978 Corolla Coupe | 1979 Corolla Hatch SR5 | <3||||||1990 Miata |||||| <3
    I like Toyota's wanna fight about it?

  20. #120
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    Quote Originally Posted by pitobread View Post
    that is one cool rare part, and basically exactly what I'm building, but without the driver control box.

    though at that price I can build 6 of my prototypes, and mine are "open source" if you understand motorola assembler

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