my speedometer is off by a guesstemated 15-20mph

chefma70

New Member
Mar 19, 2008
404
0
0
Florida
what could be the problem ? i just changed the short and long cable and every thing is tight ? anyone ever have a similar problem and how did you fix it?:nono:.......

15-20 too fast
 

ValgeKotkas

Supramania Contributor
Apr 14, 2006
2,224
0
36
35
Over the pond
Take off the speedo, take it apart, adjust the speedometer gauge (there's a metal piece you can move to adjust it (load the spring IIRC? You can search a bit, like ''speedometer'' or something, and you'll find a thread where Jeff Lange explains it) . It took me some time to get it right using an accudrill to test it (stick the drill where the needle of the cable goes and then measure the time looking at the speed and odometer reading (e.g I held the speedo reading on 60km/h, that means in one minute the odo should've showed me 1km).
My speedo needle sits now about 10mph under the 0 mark and reads the right city speed, don't know about highway.
Hope you understood something.... :)

E: Ahaa, found the link in my Favs :)
Here ya go http://www.supraforums.com/forum/showthread.php?t=217310&highlight=speedo+calibration
 

cuel

Supramania Contributor
Jan 8, 2007
1,536
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Baytown, Texas
Borrow a Tom Tom, Garmin, or other GPS navigation unit that gives a mph reading, and verify exactly how much the speedometer is off.
 

CRE

7M-GE + MAFT Pro + T = :D
Oct 24, 2005
3,485
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Denver, CO
The adjustment lever inside adjusts by percentage. So if you're off by 10% (ie you do 30 it says 33, you do 60 it says 66) then you can use the lever. If it's always off by 5, pull off the needle and put it back on where it needs to be.... sad that it has to be said, but it has come up before.