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Thread: DIY OBD1 cable (USB)

  1. #1
    Electronic Ignition!
    Join Date
    Nov 2020
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    15

    DIY OBD1 cable (USB) Build help please

    Because I'm a little slow and ride the short buss more often than I like.....

    I have a 1990 C1500 with a 5.7 and TBI. As far as I know nothing has been done to the engine or computer.

    I want to take one of the dozen or more USB cables i have laying around and make a OBD1 cable so I can try to use the TunerPro software to do some data logging. That will be a whole 'nuther story! Anyway, which wires from the USB cable need to have connections crimped on them? I think there also needs to be a resistor some place? Where can I find that without spending a fortune. I'm in the wasteland of north central Iowa so everything I don't have will have to be ordered.

    Thank you!

    Ken
    Last edited by kenh397; 02-14-2021 at 02:57 AM.

  2. #2
    Super Moderator Six_Shooter's Avatar
    Join Date
    Feb 2011
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    2,968
    It's more than just connecting a USB cable to the OBD connection. There's an interface circuit that is needed.

    You can build your own, that will interface the OBD connection and output a serial (RS232) signal, that then needs to be converted to the USB protocol.

    So in the end, it's much easier and usually cheaper just to buy the proper interface in the first place and know that it's going to work. I've built a few of my own home made interfaces for OBD1 interfacing and I now own a Moates ALDL Xtreme, because, well it just plain works reliably and is self contained (no external power needed, which many home made interfaces need, or modification of the USB to serial cable to power the home made circuit).
    The man who says something is impossible, is usually interrupted by the man doing it.

  3. #3
    Fuel Injected!
    Join Date
    Sep 2018
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    101
    Like six_shooter said ,it is very easy.You need for example the Delock 83786 usb ttl konverter ( must be a 5V one) normally amazon has it. Then you need an obd plug. (Oposite of your cars socket)
    In my case, it works perfect.

  4. #4
    Electronic Ignition!
    Join Date
    Nov 2020
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    15
    I decided to purchase a ready made cable. i got mine from 1320 Electronics LLC out of Cocoa Fl. (www.1320electronics.com) This cable has a box in between the OBD1 port and the PC. Look at the web site for more info. I was happy with the immediate response to questions and the williniuous to supply info if needed.

    Next purchase will be a lap top so I can start logging data!

    Ken

  5. #5
    Fuel Injected!
    Join Date
    Sep 2018
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    101
    Congratulation - best DIY solution.

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