Speedo needle flicks and drops to zero

Discussion in 'Technical' started by PoppaZed, Feb 5, 2016.

  1. PoppaZed

    PoppaZed Member

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    Recent occurrence while cruising.
    Speedo needle drops to zero and then returns to origional speed. Can rest on zero for a few seconds to a minute or so.
    Also while this is happening steering feels heavy.
    My 300zx is 1995 with electric Hicas.
    Obviously an electrical hitch.
    Anyone out there struck this one?
     
  2. mrkarter77

    mrkarter77 No Really, They do!!!

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    Speed sensor signal.
    http://www.pexcom.com.au/z32cms/e107_plugins/content/content.php?content.321
     
  3. grantd

    grantd Member

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    I had this problem, mine was a faulty speedo, I ended up swapping clusters out.
     
  4. Fraz

    Fraz Frazel

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    Also have had this problem, sometimes depending on the speed I was going the needle would drop down on the right hand side. speedo was faulty, put a second hand instrument cluster in and it was fine
     
  5. rodo

    rodo Senior Member

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    Me too cluster fixed it
     
  6. TWIN TERROR

    TWIN TERROR Well-Known Member

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    Mine was a dry soldered joint on the back of the speedo. There was a post in the tech section that has a photo that shows the joint that needs resoldering. A very quick fix on mine that I did years ago and has worked since. Was that long ago I can't remember if the steering was heavy.
    Cheers
    Dave
     
  7. Sanouske

    Sanouske Retired Moderator

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    Dry joints in cluster as mentioned, theres a fix for this if youre handy with an iron. Or the back of the speed sender is separating from the sender body (this is where tie signal wires enter the sender). Again there is info in the Tech Section, which also alludes to a fix.
     
  8. AAU54U

    AAU54U Member

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    I had exactly this problem. I haven't had a recurrence since I replaced the speedo sensor.

    If the steering goes heavy that implies to me the signal is dropping out not just the display. (I assume you could remove the cluster entirely and the speed sensitive steering would still work OK?). That was my reasoning which is why I replaced the sensor (and it worked in my case).
     
  9. PoppaZed

    PoppaZed Member

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    Thanks guys for your tech advice. Think I will pull cluster apart and see if something is amiss in there. Will post my result later
     
  10. TQE-756

    TQE-756 Active Member

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    Speedo & Power steering connection?

    I've had this a few time too...
    But what is the connection with the speedo and power steering, why is the power steering effected by the speedo dropping out??
     
  11. TQE-756

    TQE-756 Active Member

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    Got it!! remove my last post...

    Actually reading the article in the tech section 1st is advisable lol
     
  12. AAU54U

    AAU54U Member

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    The z32 has a power steering control module that reads the speed from the speedo sensor and adjusts power steering assistance accordingly. At low speed you have full assistance. The assistance is gradually reduced as your speed increases.

    A faulty power steering sensor can therefor change your power steering level of assistance.

    The power steering control module does not read the speedo clustor so a faulty speedometer should not effect it but a faulty speed sensor will
     
  13. IB

    IB ?????

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    Except that the signal goes from the sensor via the speedometer to get to the power steering control module.
     
  14. AAU54U

    AAU54U Member

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    Checking the wiring diagram on page ST-30 of the service manual I see you are in fact correct about that.
     
  15. CHILI

    CHILI Indestructable Target

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    If you search this subject, you will find numerous references to the Power Steering Assistance being proportionately delivered(dependant upon speed/load).
    Simply put, this means that at low speeds you recieve MORE Steering assistance, whereas, at HIGH SPEED you recieve little or none. Imagine(if you can) that FULL Assistance was delivered when travelling at say 150kph....What do you think would be likely to occur when you made a sudden alteration to the steering angle of the Front Wheels?:eek::eek:
    The faster you travel, the greater the effect of small Steering movements, therefore, Proportional Steering Assistance. :zlove::br:
     

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