1989 Sunbird - Speedo reads too fast

[HeyTomToyota]

I am trying to fix a speedometer on a 1989 Sunbird that reads too fast. I am guessing it reads 75% to almost 100% (double) what you are actually going. Around town at approximately 45 miles per hour it is reading 75 miles per hour plus.

Is there a calibration sequence? It does go down to zero at a stop. The car has the factory wheels and rims on it.

Any ideas?

[punkert87]

Dude i got the same problem with my 1989 Sunbird Gt and i cant figure it out but i hope somebody else can aswer us!

[84fiero123]

first of all are these digital dashes?
if they r they need to go to be caliberated at a local spedomiter repair shop. if not pull the gear from the trany and check it for damage, make sure its not filled with crud, also it sounds like speado gear in dash itself is trashed, take it out and have it checked at a spedo shop, if you cant find one local there is one in on the net.

http://www.carradio.com/

[HeyTomToyota]

Thanks for the suggestions. As far as a digital dash, if you are talking about the gages themselves, they are analog, but the analog gages may be getting a digital signal (I don't really know).

Your suggestions about crud or damaged gears lends me to think (I could be wrong) that crud, dirt, missing gear teeth would all make the speedometer less responsive or read slower, not faster, but I will try to locate where this is on the tranny.

I may have to take it to a local speedo repair shop, but the whole idea of this forum is to learn how to fix things yourself, if possible and avoid putting a lot of money into a very old car. Thanks for the suggestions.