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Thread: Funny adventures in electrical engineering

  1. #121
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    Nov 2012
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    Still plugging away at the 1uz PCM, however work is slowing things down. Here's a little suprise, there's a MAP sensor inside the PCM, sensing atmospheric pressure. So I guess that means it's NOT a MAP sensor, because it's not sensing manifold pressure, but it's basically the same part.



    The little hole that the arrow points to is so air can get at the sensing element, which is under a clear cover of all things.

    The PCM needs this value as the karman vortex AFM fundamentally senses air speed, not density rate, and the chemistry of combustion requires knowledge of the actual mass of air inside the engine. The measurement from this sensor, along with the air temp sensor are used to compensate the AFM measurement to get a mass flow value.

    and on a side note I've figured out most of the fueling algorithm, however the oxygen sensor corrections have eluded me thus far. Most recent update is hit to Git(hub) and volunteers are always welcome!

  2. #122
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    Dec 2012
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    Kamloops BC
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    Crazy stuff, some of this goes right over my head haha but I appreciate all the time and effort that's going in to this.

  3. #123
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    Nov 2012
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    haha! thanks. currently no time or effort is going into it though: I gotta get my car running on the same PCM. I have a commit to git sitting on my work computer waiting to be synched, but thats about it until the car is done. might be winter before I finally get the CPLD properly set up to run this one externally.

    come to think of it though I need to get my hands on a stock bluetop to test my older work with.

  4. #124
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    Nov 2012
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    So it's that time of year again: I've been working hard, spent lots of money and we have results! My supra runs happily on the modified PCM. Next up is to enrich the mixture a little and raise the rev limiter to say 7500ish



    You can see but a single flywire patching the one part of the micro I didn't understand when I spun the boards - the PORT B control lines. Toyota uses the read strobe to measure the state of the /IDL signal. The USB cable is functional and I had extensive data logging from the PCM for testing (too much, it overloaded the micro).

    Anyways, after a little tweaking I should get cracking on the ignition multiplexer, because it's winter and I shouldn't be winding the V8 up to 7500 RPM on summer tires in the snow - that's just foolish. I had it out with the revs limited at 2000 RPM and it was STILL sliding.

  5. #125
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    Aug 2009
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    Shemale lover
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    Quote Originally Posted by Sparkie View Post
    because it's winter and I shouldn't be winding the V8 up to 7500 RPM on summer tires in the snow - that's just foolish.
    What? Is that not exactly when you should be doing that?
    BCWORKS

  6. #126
    Join Date
    May 2006
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    Campbell River
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    Yeah, your valves aren't going to float themselves!

    meh, Toyota probably goes way overboard on spring pressures.

    Also, do you have a wideband on it? why do you want to enrichen?
    1JZ 1984 Celica GTS
    1UZ 1981 Corolla sedan
    ? 1972 Celica race car

  7. #127
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    Nov 2012
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    After a cold start, during warm up I feel like the car is a bit faster before it hits operating temperature. That suggests to me that a little more fuel after it warms up could be useful. Something to try which is easy.

    And yeah, mega rpm isn't realistic - but it is possible at least once. Mostly hype in that dept: the mines modified PCM cuts fuel at 7500 rpm

    As for wideband I'm planning on grabbing one and using the old post cat oxy sensor inputs to figure something out.

  8. #128
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    Nov 2012
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    Brampton, Ontario
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    This kind of thing keeps happening:



    Which should be proof enough that if you leave something within my arms reach long enough it WILL get taken apart. I think the first step would be to admit I have a problem, but I don't see it as a problem, so nuts to that.

    Trigger Happy: you may not want to sell or otherwise commit your old blacktop PCM - I'm not going to be putting it back together for a month or two at least. Sorry?

    So here's the endgame: I want to extract the Fuel and ignition maps for you guys with blacktops on aftermarket management, also the little things like the fuel injector dead time vs. voltage and how VVT is controlled. Any other requests? I'd start working on it tonight but my wife and I must watch game of thrones.

  9. #129
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    Jul 2005
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    Victoria BC
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    I like you.
    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?

  10. #130
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    Brampton, Ontario
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    and I like you! you've got some sweet projects going on yourself. lord knows if I had that much motivation against the rust my supra would look nicer than it does.

    Sorry for the late replies and slow progress - my wife and I are now caught up on game of thrones. I have sucessfully pulled the code from the blacktop manual transmission PCM and have posted it on github for all to enjoy.
    https://github.com/sparkiedk/Toyota-PCM-hacking
    Already I've identified the 2d and 3d table subroutines and I'm working on figuring which inputs end up where inside the computer. Maybe another month and y'all'll get some sweet tabular data on ignition and injection.

    As usual anyone who thinks they know anything is welcome to pull down the repository, install the free software and contribute to the disassembly. I can offer guidance as well.

  11. #131
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    Hamilton, ON
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  12. #132
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    BLACKTOP progress report!

    Redline for this PCM in normal mode: 8090 RPM

    Injector deadtime vs voltage
    Volts (V) microSeconds (us)
    6.640625 3120
    9.140625 1648
    11.640625 1104
    14.140625 800
    16.640625 544

    or as a picture:
    Click image for larger version. 

Name:	injector deadtime vs voltage.JPG 
Views:	45 
Size:	71.4 KB 
ID:	14209
    Last edited by Sparkie; 05-19-2015 at 08:09 AM. Reason: derp! forgot to mention this was all blacktop 4a-ge

  13. #133
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    Dec 2014
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    Toronto
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    One day I will maybe understand all this. After reading some of this I gotta say your old picture of Rick was a perfect one for you because that's who you remind me of, McFly too, that PCM needs more jiggawatts!

  14. #134
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    Nov 2012
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    two of my favorite fictional characters. incidentally based off eachother (of course you mean Doctor Emmett Brown, not Marty McFly).

    also deloreans are super cool too - understand that.

    anyways this thread is extra technical because it's my "build log" for these pcms - up until me there was no one stop shop for all the information for the layman to begin hacking. all the "car guys" really need from this thread is important settings like factory injector dead time, factory ignition mapping and factory fuel mapping - the idea being that they can use an aftermarket PCM with factory settings to get a good baseline without blowing up their engines.

    and my new picture is from a Japanese corolla manual from the 80's (i think it was a ae92). seemed cool to me, and especially appropriate because I have to fix Bongumons Mr2 stereo soon.

  15. #135
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    Dec 2014
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    Toronto
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    oops yah McFly is the kid lol.

    The Delorean is back at it again



    one day man, I will be able to put those numbers to use, I need to get the basics down first haha. The basics to you guys is advanced for me right now haha.

    It looks like a car rolling on an old cassete tape, does bongumons stereo still use cassete tapes? Oldd schooool lmao

  16. #136
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    Newmarket, Ontario
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    Of course my radio has a cassette deck, cd players were only in Mercedes Benz's when my car was made.

  17. #137
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    Quote Originally Posted by bongmuon View Post
    Of course my radio has a cassette deck, cd players were only in Mercedes Benz's when my car was made.
    I know those cars had cassete radio but when cheaper cd decks came out people just change out their radios to cd ones, but keeping it adds to originality of the car i guess. Vintage retro feel
    Last edited by GTyeS!; 05-19-2015 at 07:27 PM.

  18. #138
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    Toronto
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    Or is it those favourite cassetes of yours that keeps you from switching to cd player lol, my dad was like that with his, he listened to those tapes till the player busted haha

  19. #139
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    Newmarket, Ontario
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    So many mix tapes! lol

  20. #140
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    May 2015
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    lo
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    1
    this is actually really cool

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