So I got in my car this morning, started driving down the street (I wasn't actually in gear, rather slowly coasting down a hill) and noticed that the needle on my speedometer was not moving.

About 100 yards later, it perked up and started working fine.

I've seen this on other cars when the weather is bitterly cold, but the temp didn't drop below 50-55F last night, so I doubt it was weather related.

Any ideas? Is it a lack of grease or something?


PS
I thought a search would find something in the old forums, but not much came up...

 

the best people to ask that question is north hollywood speedometer

 

MrCanuck,
The problem is not all that uncommon. I'm 99% sure that this is the speedo sending unit that plugs into the side of the trans. I've done quite a few of these and is also fairly common in the 3.2 Carrera's. Not an expensive fix.
Stephen

 

starting with the 964s,i think the speed signal actually originates from the ABS speed sensors at the wheels, not the transmission.
if someone knows for sure....let us know

max

 

Likely what stephenc2s says, however .... Similar recent experience on another, non-Porsche vehicle, and it was the tach bouncing, not the speedo. The fuse for the instrument panel was corroded and not properly seated.

 

Old thread!

I experienced a lethargic speedo needle Sunday morning. I was going 30 - 40 MPH when I noticed that the speedo needle was at rest. I gently tapped the speedo glass with my knuckle and the needle immediately jumped to the correct speed. Moments later it registered somewhere north of 125 MPH...

Are there any additional thoughts on what the cause may be? This was the one and only time I've noticed it (since buying the car in September).

Andreas

 

Hey - mine did the same thing last night. I didn;t even notice it until I was well doown the road. Almost as soon as I noticed it, it popped up to the correct speed!?!? Thoughts???

mar

 

I also have the same problem which seems worse in cold weather. I start off and the speedometer jumps up from 0 to 20 MPH or so as I accelerate. I recently had the odometer gears replaced by a professional speedometer shop and I would like to think they lubed the whole works at that time. Might just be the sending unit. If we get an definite answer from someone who has gotten to the bottom of the problem, I will certainly do the repair. Happy Holidays!

 

This is happening on my car too. I took the speedo out to clean off the contacts on the back side of the assembly and thought that it might have just been the connection. I re-installed the speedo and it is still happening even after the connection cleaning. This cleaning of the connectors solved my balky sun roof switch so I thought it would be the same situation.

I have noticed this behavior on both hot and cold days. I simply tap on the face of the speedo and it pops right on.

If the sending unit is working why would tapping on the face of the speedo start it working? I do not want to take the speedo apart to clean the other contacts on the inside of the unit.