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Tach needle bouncing?

Discussion in 'The Garage' started by 87sm465np208, Jan 23, 2003.

  1. 87sm465np208

    87sm465np208 1/2 ton status

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    my tach needle bounces from like 600 to 100 and back again, and it does this on a cold morning. not all the time, just sometimes, the tach is a sunpro. truck is a 87 chevy shortbed 350TBI sm465 Np208. /forums/images/graemlins/thumb.gif.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  2. 79Beast

    79Beast 1/2 ton status

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    I have a VDO tach. It used to go crazy sometimes. It would just drop and bounce when I was accelerating. I moved the ground and now it only acts up when I am first pulling out of my street. It works as advertised almost all the time. I think my problem might lie with my Pertronix coil and HEI module.
     
  3. MJB774X

    MJB774X 1/2 ton status

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    bad connection? /forums/images/graemlins/rolleyes.gif I would re wire it, I always solder connections and connectors. if the light(when your running lights are on) doesn't flicker then you know the ground is good, check the hot and neg(coil), if the light does flicker along with the bouncey needle re do your ground /forums/images/graemlins/usaflag.gif /forums/images/graemlins/thumb.gif or could be a combination of all
     
  4. Flexy K20

    Flexy K20 1/2 ton status

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    I have an Autometer Sport Comp tach and it did that when a spark plug wire fell off. I put the wire back on and all was well. I have never had any sort of problem ever with the tach. Maybe the problem is that it's a sunpro? Try an Autometer /forums/images/graemlins/thumb.gif Hope this helps. Later
     
  5. 87sm465np208

    87sm465np208 1/2 ton status

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    cool, thanks for the input guys /forums/images/graemlins/thumb.gif. the tach came with the truck when i bought it. personally i wanna take it off. but people say it looks cool mounted there on the colum so i will just leave it on since it dosnt block my spedo or my gas gauge /forums/images/graemlins/grin.gif.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     

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