Speedo is off, how do I correct it?

He's still trying to figure out what that input is....

 

e1956v (Speedometer Service) in Colorado Springs is a very good place to do business with. Great service and very reasonable prices. They have been here forever. No worries with them.........................

 

We don't have any mile markers on our freeway. The only thing I was able to do is use the signs as a reference but even then it's not perfect. The navigation was the closest to perfect as I can get right now. With using the percent of the speedometer and odometer can't we just average it out and find a solution?

 

You can pull the speedo cable out of the trans and see what gear is on it now, then go from there....

Also if you don't plan to work on the speedometer itself, you probably should just go for the 20% correction and see how it does.

 

With the speed differance at 25%, and the measured mile at 35% you have two issues. You can take the average of the two and have a ratio adapter built, but the best way is to get it dialed in by the odometer reading first then pull the speedometer and have it calibrated (calibration in the speedometer is usually off because of wear) or rebuilt and calibrated.

 

Looking at my globe, I see that in New Zealand you are upside down. I suppose the weight of the speedometer needle comes into play, if the car was designed for use on the top side of the planet. That is also why water circles the drain backwards down there too.

 

I have checked my GPS against my three 2010 and newer Fords and all of them are off by less than 1 MPH. Even my 2009 Harley is with in 1-2 MPH!