How to Hook up an External Tach | FerrariChat
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How to Hook up an External Tach

Discussion in 'Technical Q&A' started by Jbryant, May 5, 2007.

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  1. Jbryant

    Jbryant Karting

    Sep 23, 2006
    220
    California City
    Full Name:
    Jeff Bryant
    #1 Jbryant, May 5, 2007
    I want to check my RPM on my 308 GTSI using a digital tach. The meter has a setting for 4 and 8 cylniders. I assume I use the 4 cylinder setting and hook it up to one of the coils, but I am not sure which lead on the coil to connect it to.

    Any suggestions?

    Jeff
     
  2. Ferraripilot

    Ferraripilot F1 World Champ
    Owner Project Master

    May 10, 2006
    17,879
    Atlanta
    Full Name:
    John!
    #2 Ferraripilot, May 5, 2007
    The tach reads rpm via the negative terminal. So, the signal wire should be attached to the negative side, and get a positive 12 volts from somewhere besides the + side on the coil. I hear it is not a good idea to hook anything up to the + side of the coils.
     

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