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Knock Sensor Selection outputs - M400

adam7

Hi

Im using a M400 (3.54E) for knock monitoring. Im using a home made/designed knock module based on the TI TPIC8101 and a Microchip controller. This works very well using a single knock sensor, but now Id like to explore
using multiple sensors. For this to work I wanted to use the new "Knock Selection" function in 3.54E, eg function 139/140 on a pair of Aux outputs.

As a test, using Aux 1 and function 4 (tacho) with a 2k2 pullup to 5V, I can see a clean pulse as expected, however setting the function to 139 (Knock Sensor select 1) I cant see any output from the Aux port. In fact is appears to be in high-impedance mode. Has anyone successful used these new functions (139/140) yet, and if so got any advise on how to set them up and enable them.

Notes on the setups:
From a working single knock sensor system...
Function->Knock Control->Sensor Cylinder. Definded cylinders 1/2 on Sensor 1, and cylinders 3/4 on sensor 2
Aux Output Functions -> Aux Output 1 Function 139
Aux Output Functions -> Aux Output 2 Function 140

Thanks
Adam

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Comments

6 comments

Date Votes
  • Mazi

    M800 on Porsche six flat, two knock sensors.
    INJ8....Knock Window
    INJ7....Sensor select signal (1kohm pullup to +8V)
    If I remember correctly, select signal is working only on INJ outputs. You can't use IGN or AUX outputs. With M400 could be a problem.

    Mazi

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  • adam7

    Thanks mazi, that makes sense. I realised that a "high" frequency output would be needed for knock selection, but also that the aux1/2 might well be used for DBW. Fingers crossed that the inj7 has been enabled for the knock selection finction on a M400 too, else might have to add some code to use a tap on ign1 to sync the knock controller.
    Thanks again, Adam

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  • adam7

    Appears that inj7 can't be setup for function139 (knock select) on a M400 running 3.54e firmware. Possibly an oversight and not by design. In contact with motec uk, so will hopefully have a definitive answer shortly.
    Adam

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  • cotje

    @adam7: did you ever get an answer regarding the SKM config for M400? I'm having the same issue.

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  • Stephen Dean

    For an M400/M600, Inj8 is selected for the Knock window output. This is in the SKM/OKM user manual on Page 9.

    Link to the SKM/OKM Manual
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  • cotje

    Thanks Stephen!

    I know this should be the case, but if I want to send a file with inj8 configured to the M400 it fails with the error I am not able to use that output. This M400 is running the latest fw.

    What can be the cause here?

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