Lazy Speedo - Poor man fix
 

I had the typical "lazy speedo" problem on my '83 911SC and wanted to share my super easy and $0 fix.

My speedo had the typical symptoms where it wouldn't register below 30 MPH. The strange thing is if I tapped lightly on the speedo while driving, it would come alive below 30MPH. I read through the forums and saw that this problem was typical of a failing transmission speedo sensor. I went ahead and replaced the sensor however the problem remained.

So via more searching, I found a thread stating that there may be dirt accumulated inside the speedo causing drag on the needle.

http://forums.pelicanparts.com/porsche-911-technical-forum/684428-speedometer-question.html

Apparently, at lower speeds the speedo doesn't have enough "juice" from the sensor to move the needle past this additional drag. Assuming this was the issue, I removed the speedo and planned on disassembling it and cleaning it. However I had disassembled other speedos before and knew it's a PITA so I tried one last thing before speedo surgery.

I figured if it's dirt accumulation, by moving the needle back and forth I may be able to dislodge some of the dirt. So I simply disconnected the speedo, and rotated it back and forth in my hand to get the needle to move through its range of motion. Be careful and don't rotate too hard as you probably don't want to force the needle against its stops. I did this several times and replaced the speedo.

This did it! Now my speedo works great at low speeds. Simple, cheap and easy fix!!!!

My dads '87 has the exact same problem. The needle jumps up around 25-30mph.

Can you explain a bit more how you rotated it after removing the gauge? Did you take the gauge apart and manually move the needle?

Thanks for the help!

It sounds like he rolled the speedo, and never touched the actual needle

Yup. Easy peasy. Just put the speedo in your hand and roll it back and forth to move the needle.

Thanks great tip.

It like it the easy way as I'm more of a driver than a fixer.