Results 1 to 13 of 13

Thread: NA speedometer question

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    2,000 rpm - light wheelspin, no bog here! Boo's Avatar
    Drives
    NA Miata
    Location
    Massachusetts
    Join Date
    Dec 2017
    Posts
    318
    Thanks Given
    62
    Thanked 29 Times in 21 Posts

    NA speedometer question

    I recently replaced my gauges, now I noticed my speedometer is off, from 0-30 it’s about 10mph lower than actual speed, around 50mph it’s dead on 60mph and up starts to be 5-10 mph higher than I’m actually going, I’m going 70mph odometer is reading 80mph, this is my second cluster the other cluster was off by 10 mph at all times, when I start driving the needle doesn’t start moving until I’m already doing around 10mph, completely aggravating, need some advice thanks

  2. #2
    Ninja Messiah kung fu jesus's Avatar
    Drives
    1999 White
    Location
    Atlanta, GA
    Join Date
    Dec 2011
    Posts
    15,852
    Thanks Given
    2,791
    Thanked 7,202 Times in 3,433 Posts
    There may be other issues at play here: swapped differential, different speedo gear in the transmission. I would bet one or both of those aren't original to your car.

  3. #3
    2,000 rpm - light wheelspin, no bog here! Boo's Avatar
    Drives
    NA Miata
    Location
    Massachusetts
    Join Date
    Dec 2017
    Posts
    318
    Thanks Given
    62
    Thanked 29 Times in 21 Posts
    Is it hard to change the speedo gear in the transmission?

  4. #4
    Ninja Messiah kung fu jesus's Avatar
    Drives
    1999 White
    Location
    Atlanta, GA
    Join Date
    Dec 2011
    Posts
    15,852
    Thanks Given
    2,791
    Thanked 7,202 Times in 3,433 Posts
    I don't know your mechanical experience or tools, but it's not much different than changing the transmission fluid. Check around for speed sensor replacement videos.

  5. The Following User Says Thank You to kung fu jesus For This Useful Post:

    Boo (10-04-2018)

  6. #5
    2,000 rpm - light wheelspin, no bog here!
    Drives
    Cement Grey '95
    Join Date
    Feb 2018
    Posts
    167
    Thanks Given
    90
    Thanked 115 Times in 55 Posts
    The speed sender is easy to replace. Remove speedo cable (NA) or unhook electrical connector (NB), remove one 10mm head bolt, swap sender, reverse for installation.

  7. The Following User Says Thank You to Midtenn86 For This Useful Post:

    Boo (10-04-2018)

  8. #6
    3,000 rpm - starting to feel the power mazdarati1's Avatar
    Drives
    With a blinker on
    Location
    Michigan
    Join Date
    Sep 2014
    Posts
    631
    Thanks Given
    494
    Thanked 232 Times in 106 Posts

    Speedometer

    I have read in a number of places that NA speedometers are notoriously inaccurate, my car is 5 mph low across the scale. You may get an idea how accurate your car is by checking the speedo against a GPS speed read-out.

  9. The Following User Says Thank You to mazdarati1 For This Useful Post:

    Boo (10-04-2018)

  10. #7
    2,000 rpm - light wheelspin, no bog here!
    Drives
    Cement Grey '95
    Join Date
    Feb 2018
    Posts
    167
    Thanks Given
    90
    Thanked 115 Times in 55 Posts
    They definitely aren't the most accurate. For example, I swapped to a 6 speed and 3.9 final drive in my NA. I put in a 4.1 sending unit (tallest I had laying around for a cable driven speedo) and my speedo is pretty close (+/- 1mph minus my error in installing the speedo needle) to a GPS.

  11. #8
    2,000 rpm - light wheelspin, no bog here! Boo's Avatar
    Drives
    NA Miata
    Location
    Massachusetts
    Join Date
    Dec 2017
    Posts
    318
    Thanks Given
    62
    Thanked 29 Times in 21 Posts

    NA speeed sensor

    My speedometer is off by 10 mph, does not move off 0 till I’m going around 10 mph, if I change the sensor do I want more teeth on the gear or less teeth? Thanks

  12. #9
    2,000 rpm - light wheelspin, no bog here! DarylSibcy's Avatar
    Drives
    Red 1990 Miata w/ITBs ;)
    Location
    Isle of Man - Middle of... Somewhere...
    Join Date
    Oct 2015
    Posts
    464
    Thanks Given
    258
    Thanked 279 Times in 150 Posts
    Is this for one of the NA's in your profile pic??

    If so, the NA speedo's were never mega accurate from the factory anyway. Mine does the same, but I've never worried about it enough to "fix" it, I've always got something else that needs doing first (and usually more expensive )

    As long as your speedo is accurate from 10 upwards, I wouldn't worry personally - someone else might have better advice though HTH
    You want a good car. I want a good miata.

  13. #10
    2,000 rpm - light wheelspin, no bog here! Boo's Avatar
    Drives
    NA Miata
    Location
    Massachusetts
    Join Date
    Dec 2017
    Posts
    318
    Thanks Given
    62
    Thanked 29 Times in 21 Posts
    I wish that is was but it’s totally off by 10mph every speed you go, except when you go 50mph and after that it’s 10mph faster than the speed your going, totally messed up

  14. #11
    Ninja Messiah kung fu jesus's Avatar
    Drives
    1999 White
    Location
    Atlanta, GA
    Join Date
    Dec 2011
    Posts
    15,852
    Thanks Given
    2,791
    Thanked 7,202 Times in 3,433 Posts
    There are different speed sensor gears for the three main differential gearsets in the Miatas. They are different colors, too, IIRC.

    You should also list your tire/wheel specs too, as that may also be playing into the issue.

    Please keep all the your questions about this issue in this thread.

  15. The Following User Says Thank You to kung fu jesus For This Useful Post:

    Boo (10-08-2018)

  16. #12
    2,000 rpm - light wheelspin, no bog here! riefdaddy's Avatar
    Drives
    94 Red NA
    Location
    Yorktown, VA
    Join Date
    Aug 2012
    Posts
    368
    Thanks Given
    107
    Thanked 167 Times in 96 Posts
    More teeth would get it closer, or smaller tires, or a higher gear ratio.

  17. #13
    2,000 rpm - light wheelspin, no bog here! Boo's Avatar
    Drives
    NA Miata
    Location
    Massachusetts
    Join Date
    Dec 2017
    Posts
    318
    Thanks Given
    62
    Thanked 29 Times in 21 Posts
    If my cluster is not moving till it hits 10mph, l would want a gear with more teeth?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •