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What makes a tach bounce ?

Discussion in 'The Hokey Ass Message Board' started by Dirty2, Feb 12, 2011.

  1. Dirty2
    Joined: Jun 13, 2004
    Posts: 8,903


    Just wondering after I read an add for a tack for sale . Myself I have a greenline tach that I notice every once and a while bounce . Any ideas what causes it ?
  2. Harms Way
    Joined: Nov 27, 2005
    Posts: 6,869

    Harms Way

    This will usually happen if you don't bolt it down,... or secure it to something, Or if it's really, really happy !... I hope this helps !,........ (I bet it happens more often when you hit bumps,..huh ?)
    Last edited: Feb 12, 2011
  3. daddio211
    Joined: Aug 26, 2008
    Posts: 6,002


  4. tanof
    Joined: Sep 26, 2010
    Posts: 107

    from New Mexico

    Sorry to hijack this post, but what makes a tach go back to zero while running the car? When I go down extreme hills or ramps, my tach goes to zero while the engine is in drive running.

  5. r8odecay
    Joined: Nov 8, 2006
    Posts: 787


    mechanical? lube the cable...
  6. It bunny hops when its happy. :D

    First we need to determin what kind of tach it is. A mechanical tach has a tendency to bounce more that a modern electronic tach for instance. They do that by nature then it gets worse as things start to wear.

    The older electrical tachs have a tendency to bounce because they have been running and vibrating for a long time. The older movements were not as stable to start with. Now 40 years later there is corrosion and poor connections in the movement itself compounded by poor wireing to whatever ignition source you are using.

    For your tach to operate perfect everything needs to be perfect.
  7. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    depends on how far off the ground it is when you drop it...:eek::D
  8. also can be an indicator of ignition problems if its electric.. loose spark signal you will drop to 0 and if it comes back quick enough it will just bounce but since ya didn't say anything about the engine skipping I don't think that is the case.. what tach is it, and what kind of ignition is it?
  9. Bad Shock Absorbers >>>>.
  10. DuckusCrapus
    Joined: Jun 24, 2004
    Posts: 492


    I have had this happen on a few tachs through the years. Bad ground is a good place to start looking.

    I had a Mallory tach that would bounce due to the temperature and humdity outside. Very frustrating.

  11. Blue Moon Garage
    Joined: Mar 1, 2009
    Posts: 287

    Blue Moon Garage

  12. The Shocker
    Joined: Dec 30, 2004
    Posts: 3,538

    The Shocker

    Thats my guess as well .I had a cheap ass Equis tach in my Dodge when i got it and the needle would bounce like Hell in the burnout box sometimes and then it finally just bounced more than it didnt all the time .Replaced it with an Auto Meter (not the cheap Auto gauge knockoff) and the needle is as steady as a rock all the time.Im using the same ground location that the cheapo had and no problem .When it comes to gauges i have found you get what you pay for ...
  13. Alternator/regulator problems can cause flutter in electronic tachs.
  14. Mozes
    Joined: Nov 16, 2006
    Posts: 155


    Hip hop and gangsta rap.
  15. Dirty2
    Joined: Jun 13, 2004
    Posts: 8,903


    Its a stewart warner greenline . Its electronic not mechanical . Its mounted to the steering column . I dont run alternators only generators on my 32 . It dosent really bounce it kind of floats , if that makes sense . Thanks for all the help . I think its just old like me ![/QUOTE]
  16. willowbilly3
    Joined: Jun 18, 2004
    Posts: 4,356

    Member Emeritus
    from Sturgis

    Danny, you running points? I used to have one that would act up a little when the points needed changed.
  17. Dirty2
    Joined: Jun 13, 2004
    Posts: 8,903


    I'll try all these tips . Thanks yall .
  18. Deuces
    Joined: Nov 3, 2009
    Posts: 20,093

    from Michigan

    I prefer to watch boobs bounce..:eek::eek:
  19. hiboy32
    Joined: Nov 7, 2001
    Posts: 2,775

    from Omaha, NE

    The tach in my coupe was a cheapy from partstore started bouncing after the rain was running out the back. Then it would stop bouncing in the rain. Then later it just stopped doing anything. I would have to say water can make a tach bounce.

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