Wideband Gauge/Sensor Causing Radio Interference

Discussion in 'I.C.E & Electrical' started by pretzil, Jun 21, 2016.

  1. pretzil

    pretzil 2 AYC Bars Premium Member

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    Hi guys,
    Ever since I fitted my wideband AFR gauge it has caused radio reception issues, the audio is perfectly fine if I run from a USB or AUX, and that is what I have done until now, but I got sick of it on a long drive on the weekend.
    The interference occurs whether the engine is running or not.
    Has anyone else come accross this problem?

    My wideband is an Innovate MTX-L. The head unit is a pioneer double din touchscreen and it only uses a single aerial input, but I am not sure where that aerial is... Rear windows?

    The wiring runs through a grommet where the clutch would go in a manual and runs along the back of the ECU stack to the gauge in the glovebox.

    I have it using the ciggy lighter plug as a power source and grounding through a chassis bolt that the factory wiring also uses as a ground.

    I have tried changing power source, grounding location, adding a ground to the earth that goes directly to the sensor (rather than thru the gauge) and no success. I have also tried running the gauge in the drivers footwell so it goes no where near the head unit and associated wiring, straight thru the firewall and onto the floor.

    This is doing my head in, anyone got any ideas other than 'Check your grounding' that I get from a google search on the issue?

    Thanks,
     
  2. BCX

    BCX 1 AYC Bar Premium Member

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    Find a new power source for your gauge, not from accessories, maybe from ign... the heater circuit in the wideband is noisy as.

    Will post a screenshot from my oscilloscope soon.
     
  3. pretzil

    pretzil 2 AYC Bars Premium Member

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    Hey, thanks for the suggestion, unfortunately I just came back inside from hooking the wideband up to a jumpstart pack outside the car, a 12V source completely independent of all the wiring in the car... Still gives off interference :(
     
  4. BCX

    BCX 1 AYC Bar Premium Member

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    I completey forgot about this... but I've gotta head outside tonight with the oscilloscope again to test a few things... so i'll grab a screen shot. I've also got the MTX-L.

    But in terms of a solution... maybe a largish value cap near the gauge (perhaps with a diode depending on what kinda of current the thing draws) to kinda prevent the gauge from inducing noise into your electrical system. Might play with mine tonight to see if I can suppress the noise.
     
  5. BCX

    BCX 1 AYC Bar Premium Member

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    Here's a screenshot of the noise the MTX-L creates (this is just ign on, not engine started otherwise will be heaps of other noise):
    DS1Z_QuickPrint3.png


    Cursors set showing freq and voltages:

    DS1Z_QuickPrint2.png


    zoomed up:

    DS1Z_QuickPrint4.png

    I assume they are Pulse Width Modulating the heater for the sensor. As the dutycycle varies.
     
  6. pretzil

    pretzil 2 AYC Bars Premium Member

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    Thanks, what does this mean?
    Do you get radio interference too?
     
  7. BCX

    BCX 1 AYC Bar Premium Member

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    I dont have my gauge mounted near my radio... it just lives in my glovebox.

    Not sure what you can do here... more showing why/whats causing the noise.
     
  8. pretzil

    pretzil 2 AYC Bars Premium Member

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    ITS GONE!

    I went to Jaycar and got a pack of clip-on ferrite beads, I put them on the aerial cable, the wideband power and the wideband signal cables, no idea which one did the trick but for the first time in over a year I have crystal clear radio reception!
     
    Kaldek and Badger like this.

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