Hi KMoffett, ericgibbs, 3v0, Chaerl, DirtyLude,
Thank you all for your replies.
This project would be to display on a PC screen, the information from the ECU outlet port on the car.
This project would not be for altering the engine management controls.
This project would be principally to assist in fault-finding.
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I have visited a few 'Open source' type internet pages, but i am unclear about the program downloads offered.
They seem to be aimed at people wanting to alter the existing management controls.
All i am looking for is a display, to show the signals from the various sensors around the engine/car.
Such a display is a far more within the scope of a computer.
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Altering parameters within the control unit would probably require a box of tricks to re-program settings that are not normally accessible.
And probably also a much deeper in depth knowledge of the particular unit used.
This is not the intention here, and probably could not be done using a computer alone.
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This project is to help to get things running properly, not to alter them.
Mainly for engines that wont run properly, or not at all.
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The guy that asked me to look into this has not been back yet, but he has told me that he has obtained some of the necessary leads to couple on to the 'port' on a vehicle, usually under the bonnet.
I am still reading through the stuff about 'Opendiag' and 'Freediag' and 'Scantool', but so far i dont think they are quite what i am looking for.
I just want a display from the engine 'port'.
John