Autometer Tach install

Discussion in 'Small Block Tech' started by Mark Demko, Feb 23, 2019.

  1. Mark Demko

    Mark Demko Well-Known Member

    Got the tach in place.
    Looking at the chassis manual, its showing a one prong connector, and I have a two prong going to the factory tach.
    Anyhow, on my two prong connector, I have 12 volts on both the brown, AND orange wire.
    The chassis manual isn't telling me much as far as wiring color, OR Im missing it:eek:
    Which one is the signal wire for the tach?
     

    Attached Files:

    Last edited: Feb 23, 2019
  2. Mart

    Mart Gold level member

    Maybe Larry knows.
    I ran a separate wire to the MSD box.
     
  3. CJay

    CJay Supercar owner Staff Member

    A factory tach has a single brown wire going to it that runs to the coil. It was taped onto the dash harness.

    That two prong connector looks like its for the clock.
     
  4. telriv

    telriv Founders Club Member

    Agree with Jason
     
  5. Mark Demko

    Mark Demko Well-Known Member

    IMG_3600.JPG
    This is what I have for the clock plug, its a two prong "T"
    My factory tach has an "L" shaped two prong connector IMG_3593.JPG
    Ima thinking the brown wire is signal???
     
  6. Mark Demko

    Mark Demko Well-Known Member

    LAAAARRRRRRY:)
    I do know that I added the MSD Tach adapter many years ago???
    That's the downfall to owning the same car since '85, yah don't remember what all you did to it:mad:
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    That is the connector for the clock. The clock works all the time, so the orange is full time 12 volts, the black (it's not brown) is ground. You can't use that for power for the tachometer. You can use the ground connection if you like. The gray is lighting, tap into that. Run new wiring for everything else. Run an ignition on 12 volt lead and a new signal wire.
     
    Last edited: Feb 24, 2019
  8. CJay

    CJay Supercar owner Staff Member

    You likely don't need the tach adapter. Most aftermarket tachs are made for use with MSD box directly. So you can probably ditch it.
     
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  9. Mark Demko

    Mark Demko Well-Known Member

    That's probably what I'll end up doing, and run a new wire from the tach output of my MSD 6A to my tach.
    Wish I remembered what I did 20 some years ago:mad:
     
  10. Mark Demko

    Mark Demko Well-Known Member

    IMG_3601.JPG
    I actually read the directions, this warning kinda tripped me up:rolleyes:
    See, reading directions causes panic:mad:
     
  11. CJay

    CJay Supercar owner Staff Member

    Right, you don't connect the tach directly to the coil if you have MSD, its gotta go directly to the box. . On my old 6A box, there is a tach output connector on the side that my signal wire is connected to . In fact, I run a factory tach off my 6A box
     
    Mark Demko likes this.
  12. Mart

    Mart Gold level member

    Get it all buttoned up Mark?:)
     
  13. Mark Demko

    Mark Demko Well-Known Member

    LOL, not yet, HOPEFULLY this weekend, suppose to be 48 Saturday and 51 Sunday
     
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  14. Mark Demko

    Mark Demko Well-Known Member

    BBA3B30E-0ED3-4842-B83F-2B8F4BC9C545.jpeg Got ‘er wired and working, took a vid while on my knees on the garage floor and working the gas with my hand, man this was easier 30 years ago:rolleyes:
     
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  15. Mark Demko

    Mark Demko Well-Known Member


    Heres the vid
     
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  16. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Yeah, even if the job had to be done more than once because of being young and dumb, it was still easier!:rolleyes::D
     
    Mark Demko likes this.
  17. Mart

    Mart Gold level member

    Pain in the rear, isn't it? Looks good! It's a must do because the factory tach is a 6 grander.
    20141230_171046.jpg 20141230_171046.jpg

    See that tiny button above the defroster switch? shhhhhh, don't tell Guy.:D
     
  18. Mark Demko

    Mark Demko Well-Known Member

    Mart, why is the chrome on your dash so much nicer than mine:cool:
    It looks awesome!
     
  19. Mart

    Mart Gold level member

    2nd owner from '76. Dont touch it!:D
     
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