Help with tach wiring

Discussion in '1974 Specific' started by erials, Apr 4, 2020.

  1. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Glad you found it!
    The tach filter smooths out the signal to the tach and prevents the needle from bouncing. Especially at lower RPM readings.
     
  2. erials

    erials New Member

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    Ahh ok! Got it. Thanks that makes sense.
     
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    My Haynes manual wiring diagram has a note next to the tach filter... "USED WITH RADIO"
    So, maybe it has two purposes. Radio static and signal smoothing.

    I've also read that the tach will work fine without it.
     
  4. erials

    erials New Member

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    Good to know. If my soldered wire comes apart I’ll try to by pass the filter and run a straight wire from the harness to the negative side of the coil. I’m running an external condenser with my pertronix right now anyway so I should have the radio static suppression without the tach filter. So far the car runs very well right now and the tach is functioning fine with my repaired tach filter wire. Thanks for your input on this.
     

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