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stock tach is not working. UPDATE- What is the capacitor?? See last post

Discussion in 'The Garage' started by jakeslim, Feb 23, 2004.

  1. jakeslim

    jakeslim 1/2 ton status

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    I am now going after the little things on the k5....

    My tach was working but after I installed a new distributor and fumbled with it(timing) for a while, the tach is not moving when driving. Now it does move down to "0" when I turn the truck on, but no movement once in drive. I don't think I fried anything....where should I check and not check

    oh yeah:1977 k5
     
  2. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Re: stock tach is not working.

    Check the connecter for the "tach" lead on the distributor cap (right next to the main ignition wire), this is where the tach gets its signal from. Most likely it's a connecter issue, the fact that the tach zero's out when you turn the ignition on indicates it should be ok.
     
  3. mouse

    mouse 1/2 ton status

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    Re: stock tach is not working.

    I traced down a problem with mine to a broken wire about 6 incehs from the distributor where the wire connected to a capacitor. Look around that area, the break was hiding from me.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    Re: stock tach is not working.

    I fixed one just as mouse described. The wire had broken off of the inline capacitor. (And the dealer knocked some bucks off the price of the truck since it didn't work! /forums/images/graemlins/thumb.gif ) Once I soldered that back together it worked great. /forums/images/graemlins/cool.gif
     
  5. conoverbandit

    conoverbandit 1/2 ton status

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    Re: stock tach is not working.

    ( hijack)A capacitor? hmmmmmmmm, that may be why mine goes crazy when ever I hook it up....Never seen one from tach lol, I thought they just hooked up straight /forums/images/graemlins/rotfl.gif.Mine zero's out when switch is in on postition but when running it acts all right at idle, but it just stays there when reving engine. I turn the wires around, and it zero's out but when cranked and runing, it's redlined at idle.Any ideas? I think I need to just pull that thing out and get another type dash that is supposed to be init.This truck did not have fac. tach, was orginal 6cyl truck so I think idiot lights? Some one changed it before i got it...........Need to figure this out it's bugging me to pieces lol. Any ideas?(/hijack) /forums/images/graemlins/rotfl.gif
     
  6. jakeslim

    jakeslim 1/2 ton status

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    Re: stock tach is not working.

    Ok, i fixed mine today /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif The wire had split when I was working on timing issues last spring. It was up in the plug(to distributor) and no easily seen. All fixed and so coooool to have a working tach. /forums/images/graemlins/woot.gif /forums/images/graemlins/woot.gif
     
  7. jakeslim

    jakeslim 1/2 ton status

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    Re: stock tach is not working.

    wait a minute...what does the inline capacitor look like? I did remove some molted piece of plastic thing that was about 10" away from distributor....i bypassed it(cut it out). Everything is working ....I wonder if that was my "inline capacitor" /forums/images/graemlins/confused.gif /forums/images/graemlins/thinking.gif /forums/images/graemlins/whistling.gif
     
  8. mouse

    mouse 1/2 ton status

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    Re: stock tach is not working.

    On my blazer the capacitor is wired to a short, 6 inch or so, piece of wire that has one connector attching to the distributor and the other to the tach wire coming out of the firewall. The capacitor is held onto the firewall with a small sheet metal screw. The capacitor looks like one inside of a points type distributor - a silver cylinder, probably with a diameter smaller than a dime. Hope this helps. By the way, the capacitor will "clean" the signal from the ignition going to the tach and should make it more accurate. Of course if the tach is old, it could be off by a few hundred rpm, especially at higher rpms.
     

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