Results 1 to 6 of 6

speedometer off

This is a discussion on speedometer off within the Firebird / WS6 forums, part of the Vehicle Specific category; ok so the speedo on my 2000 t/a 5.7L m6 gets more and more off the faster i go. at ...

  1. #1
    1BADLS1
    Join Date
    Apr 2011
    Location
    WV
    Age
    29
    Posts
    17

    Black
    2000 T/A LS1 M6

    speedometer off

    ok so the speedo on my 2000 t/a 5.7L m6 gets more and more off the faster i go. at 35 mph i am about 3 mph off. but at 70mph on my gps i am only going 55mph on my speedo. it has stock 3.42 gears and stock tire and wheel sizes. i am guessing something has gone bad i.e a sensor or something. however, i am not too familar with this system and my hanes manual doesn't go into the speedo.

    so what do i need to look at and where are the things i need to look at. any troubleshooting tips or suggestions of how to figure this issue out?

  2. #2
    Just me Y2KPewterSS's Avatar
    Join Date
    Nov 2006
    Location
    Broken Arrow, OK
    Age
    42
    Posts
    23,353

    Pewter metallic
    2000 Camaro SS

    Quote Originally Posted by wvbrett View Post
    ok so the speedo on my 2000 t/a 5.7L m6 gets more and more off the faster i go. at 35 mph i am about 3 mph off. but at 70mph on my gps i am only going 55mph on my speedo. it has stock 3.42 gears and stock tire and wheel sizes. i am guessing something has gone bad i.e a sensor or something. however, i am not too familar with this system and my hanes manual doesn't go into the speedo.

    so what do i need to look at and where are the things i need to look at. any troubleshooting tips or suggestions of how to figure this issue out?
    Just a thought here, are you sure your GPS is accurate?

  3. #3
    Senior Member
    Join Date
    Jul 2005
    Location
    Jacksonville, FL
    Posts
    2,725
    Get someone next to you on the highway at 70 and tell us what your RPM is at the same speed in 6th.

  4. #4
    1BADLS1
    Join Date
    Apr 2011
    Location
    WV
    Age
    29
    Posts
    17

    Black
    2000 T/A LS1 M6

    when i bought this thing my buddy drove my 2010 f-150 back. i called him, as he was following me, and asked what i was going in my truck. he said 70mph. so my gps is accurate. i'll check again, but my rpm's at 70 (according to the gps and truck) were right around 1500 in 6th gear i do believe.

  5. #5
    Member Ant71130's Avatar
    Join Date
    Aug 2010
    Location
    Lebanon, OH
    Age
    28
    Posts
    356

    Black
    2002 M6 WS6

    Quote Originally Posted by wvbrett View Post
    ok so the speedo on my 2000 t/a 5.7L m6 gets more and more off the faster i go. at 35 mph i am about 3 mph off. but at 70mph on my gps i am only going 55mph on my speedo. it has stock 3.42 gears and stock tire and wheel sizes. i am guessing something has gone bad i.e a sensor or something. however, i am not too familar with this system and my hanes manual doesn't go into the speedo.

    so what do i need to look at and where are the things i need to look at. any troubleshooting tips or suggestions of how to figure this issue out?
    Had a similar issue once. First thing, are you sure it haas the stock gears? You're probably right, but my next question would be, how many previous owners? Are you positive the guy before you didn't change the rim/tire size and then the dealer switch them back? My speedo was off when I bought my car as well, more so the faster I went obviously and my mom was wondering why I was going 50 the whole way home when I tried going 70-75. It was a 12 hour drive lol. My point being, I called the dealer and had them look up the previous owner, apparently he had put 20" rims on it and the dealer guy replaced them back to 17"s. Which is fantastic because imo it would have looked horrid with 20s but, moral of the story, it wasn't recalibrated/tuned afterwards. That's the only reason I bought my handheld tuner, in case I needed to change that or rpm limits, things of that nature. Might be worth looking into. The car's past I mean.
    Last edited by Ant71130; 06-06-2011 at 11:47 AM.
    2002 Black/Ebony M6 WS6: Lid, Filter, Smooth Bellow, P&P TB (!Bump Stop), Magnaflow Cat-Back (dumped after the axle), 4.10s, Hypertech ME Tune, eibach springs 4/4, LCA relocating brackets, PHB, free mods, 17" TTMs.

  6. #6
    Senior Member Whamhammer's Avatar
    Join Date
    Sep 2010
    Location
    Bel Air, Maryland
    Posts
    1,324

    Silver
    '02 Trans Am WS-6, 6M

    WHat you might want to try doing is test the speed at incriments of 5 mph with a friend and not the variance in speeds shown. Then do some division to figure what the percentages of the variances are. If the variance is consistant, reprogram the pcm to compensate. I'd give it a plus/minus factor to take into account tire wear, etc.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Improving Pontiac Speedometer Accuracy - Speedometer Super-T
    By Ed Blown Vert in forum Firebird / WS6
    Replies: 0
    Last Post: 02-27-2012, 10:10 PM
  2. 110 MPH speedometer on Z28
    By Dave-TransAm in forum Camaro / SS
    Replies: 13
    Last Post: 03-24-2010, 08:39 PM
  3. Speedometer
    By Dave-TransAm in forum Firebird / WS6
    Replies: 2
    Last Post: 03-12-2010, 10:53 PM
  4. Speedometer WAY off need some help!
    By ziominix in forum General Help
    Replies: 21
    Last Post: 05-13-2009, 07:13 AM
  5. speedometer help
    By shortbed454 in forum Stereo and Electronics
    Replies: 0
    Last Post: 01-13-2006, 11:25 AM

Bookmarks

Posting Permissions

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