Megasquirt Newbie Questions - All the really dumb ones you were afraid to ask!

Discussion in 'Throttle bodies & non-OEM ECUs' started by Mike_H, Apr 27, 2010.

  1. Mike_H Forum Addict

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    I'll save you the trouble, as I haven't got a clue about this.

    I'm installing Megasquirt in the track day car (See my sig for a link) and I'm suffering from information overload a bit, so I want to try and distill it down to a few simple questions that are blocking me from making progress.

    1. I've borrowed a laptop from a mate (as my MacBook isn't compatible without a lot of backwards configuration to a previous O/S release) and it even has serial ports on it, so that makes things a bit easier. However, I need to go out and buy a lead to connect it. Can someone confirm if it's a 9pin male to 9pin female that I need, and not a 9 pin to 25 pin.

    For example:
    http://www.maplin.co.uk/Module.aspx?ModuleNo=97735


    2. I've downloaded the latest version of Megatune, and that seems to have installed successfully. I started up MTCFG, and selected one of the MS versions (just to see if I could find the menu option) but when I look at File=>Activate, it's greyed out - no matter which node I select first. Which schoolboy error have I probably made?
    From: http://www.megamanual.com/ms2/configure.htm
    I previously installed and uninstalled the software. Could it be that it thinks there's still a file installed from the previous attempt?

    3. Is it worthwhile (and safe for the ECU) to connect it to the PC and see what's on there, or does it need to be fully installed in the car and powered up, before the PC will read it? I guess there's no power feed down a COM port, so I'm wasting my time thinking about this.


    That'll do for now. There WILL be more questions later :lol:
     
    Last edited: Apr 27, 2010
  2. Mike_H Forum Addict

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    I've just figured out point 2 - because of where the tree was scrolled to, I couldn't see the right node to click on. I just need to check with my esteemed supplier which .INI file I need now :)
     
  3. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Mike answers on your PM.
     
  4. bertelli_1 Forum Member

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    Make sure you get the correct type of db9 cable, you need a straight through type (where pin 1 connects to pin 1, pin 2 to pin 2 etc), there are different types available! Yes, it is a db9 to db9, not 25.
     
  5. bertelli_1 Forum Member

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    Toyo beat me to it! Damn you!
     
  6. Mike_H Forum Addict

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    Don't worry. I'll have more questions for you - check back in tomorrow ;)
     
  7. Brookster

    Brookster Paid Member Paid Member

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    Nice one Mike

    didn't realise you were going MS !! welcome to a world of Frustration must admit i've learned alot in the past 4 weeks ! lol

    I found a PCMI - DB9 Card best for the coms 7 off ebay :thumbup:
     
  8. Mike_H Forum Addict

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    Yeah I saw that, but I've got a COM port on the PC, so I just need the cable.

    I've had the ECU for 18 months, so it's about time it actually got near a car!


    EDIT: By the way, others are welcome to add their newbie questions in here. Hopefully it will turn into a useful reference thread for MSEFI newbies.
     
    Last edited: Apr 28, 2010
  9. Brookster

    Brookster Paid Member Paid Member

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  10. bigbeat

    bigbeat Forum Member

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    I made my own db9 male to female cable and from work and worked a treat. Could throw one together for you at n cost take me about 10 minutes to make one at whatever length you want
     
  11. Brookster

    Brookster Paid Member Paid Member

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  12. bigbeat

    bigbeat Forum Member

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    Or I can do a DB9 to DB25 cable. With either connector. As they are both for RS232. Its only 5 wires as well
     
  13. HidRo Forum Member

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    Well, if you want a noob question, then:
    What's the main difference between 3.0 and 3.57, and which is recommended? :lol:
     
  14. bigbeat

    bigbeat Forum Member

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    Same function. One is plated through hole. The other is surface mount.
     
  15. Mike_H Forum Addict

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    I've got an innovate LM-1 for the wideband checking of AFR. I'm planning to stick a gauge in the car, but there's a long list of jobs ahead of that one.
     
  16. HidRo Forum Member

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    And not other differences? I thought there were a few. Thanks!:thumbup:
     
  17. Mike_H Forum Addict

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    Got one, thanks - provided it works.
     
  18. Mike_H Forum Addict

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    Right... I did say there were more questions to come. I've started wiring in the ECU, and there are a couple of places where I'm confused by the wiring diagram (pinched from Toyotec's MS FAQ).
    [​IMG]

    1. Injector Channels - I think I only need to use one channel, and I've got a digi injector loom and plug, and the diagram seems to show the two wires connected to two different injectors. So, I'm not sure whether:
    A - I attach one yellow wire to each terminal on the digi loom (and the earth for the injectors is through the ECU
    B - or whether I want one of the yellow wires, and the other ones is an earth.

    2. Coolant temp sensor and air intake temp sensor seem pretty straightforward - one powered feed from the ECU, and one earth. Does using the 2 pin coolant temp sender make any difference to this (does it have a separate power feed, for example). I'm assuming not for now, but if I'm going wrong here, feel free to correct me.

    3. TPS -I've got a 3 pin TPS from an Audi 80 (courtesy of Danster, ages ago), and I'll go and see if I can figure it out with the multi meter, but I'm not sure which terminal is which. The wiring plug I have has 3 wires, and the terminals are numbered 1-2-3, corresponding to 4-5-6 on the TPS end of the plug.

    TPS Wires are:
    T1. Green/Brown
    T2. Blue/Black
    T3. Blue/Brown

    I'm guessing Blue/Black is the 5v, and Green/Brown is the earth, just from general knowledge of VAG wiring colours. Anyone know for sure, or give me a guide how to test them?

    4. Distributor
    - Pin 24 on the ECU is the Tach signal to the ECU - anyone know which pin on the VW 3 pin hall sender that is?


    I expect I'll have more later ;)
     
  19. Mike_H Forum Addict

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    This seems to answer some of it:

    http://www.megamanual.com/v22manual/mwire.htm

    So I think that's the temp sensors sorted.

    Injectors
    So that clears up a couple of issues I think. If anyone thinks I've got that wrong, please shout!
     
  20. bertelli_1 Forum Member

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    Mike, this is the wiring diagram I did for my digi 8v -
    [​IMG]
    There is some info on THIS page you may find useful. The above diagram doesn't show the pullup resistor I fitted to the hall sender.
     
    Last edited: May 1, 2010

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