speedo
 

Gentlmen, I have done a search and have looked at countless pages and can find nothing that will tell me why, in my 83 300sd, the speedo reads faster then I'm going, the faster I go, the more it is off,it reads 75, i'm going around 60, more or less. If anyone has any ideas, I would love to hear them, thank you very much steve

You could, of course, have some mismatched components somewhere driving it with the wrong ratio. Or you could have a worn speedo mechanism, do a search on google for "2002 speedo repair" and find an article written for BMWs and see if it could describe what you've got going on. It pointed the way for me to fix my speedo!

thank you Don XVI for your response, I'll try that. steve

It happened to me once on a 91 Mercury. It turned out to be a corroded and worn out speed sensor. No codes were set. And yes, the speedometer was showing faster than I was going. It showed 90 when I was doing 70.

Re: fast speedo reading problem solved?
 

Hi Steve,

I was just wondering if you ever got around to solving this problem. I have an '85 190E 2.3 8V and you've basically described my problem right on the money.

hope to hear from you ......... thanks!

the cable may need to be replaced or
 

it might be happen if you changed tire size from the factory ones. This happens because the computer is coded for whatever size is put on the car at the factory. Just take it in and have it re-shot for the new tire size if you did change the tires/rims out.:)

now the speedo is all over the place, at 80 it reads 40 , at 40 it reads 0 . then it goes back to 75 at 80, I'm realy confused, but wath else is new? steve

Guys, after more reading,I know its the speedo or the pick-up in the tail shaft.So I figured to look at both these this week. I took big blue out to 495 interstate to clean out the motor. About 10 minutes at 80 or so does the trick. Low and behold, does't the speedo start to work. Now it seems fine, for how long,I can only guess. I guess I should check it anyway, but I'll wait. steve