Speedometer sending unit frequency

[Vigri]

Hi,

I got the speedometer back from electrician last week and it turned out that it was a combined mistake. One problem was that the speedometer needle position was not correct. After correcting this, speedometer was still showing 100km/h when actual speed was 110km/h. This problem was solved by adjusting the potentiometer on the speedometer unit.
I haven’t road-tested it yet but on the table it was tested up to 160km/h and it showed correct speed the entire range.

BR,
Vigri

[Enrico]

Hi,

Can you please confirm precisely how you adjusted the potentiometer and where it is?

On my Ghibli I have a similar problem: whereas below 70 km/h speed is shown correctly (verified with GPS), above it shows up to 10 km/h less than the actual speed on GPS. (and my wheel size are correct). Showing more would be fine, but less is unacceptable.

Thanks for any help

[Vigri]

Hi,

These pictures are not from my speedometer but they tell the story.
Potentiometer is this “screw” marked red on the picture.
   
   
It is on the bottom side of speedometer connected to circuit board. It should be covered with silicon from factory to fix the position.
To adjust it just use a screwdriver. As I didn’t do it myself I cannot tell you how much and to what way you need to turn it but just start with little adjusting to either side and test how much it changes.
Because you need to take speedometer out from this plastic dashboard unit some people have drilled hole into it, so you could do it without removing it.
   

BR,
Vigri

[Enrico]

Thanks. When I un mount my dashboard the speedometer is not sticking out on the back side like on your third picture. I guess this means I would have to take apart the dashboard itself to access the screw.

Perhaps someone else can provide additional advice?

[Thorsten Ruge]

Yes, just pull it of the pins man and adjust at the side like marked:

 

Enrico, that Vigri cannot find those multiple posted tacho-issues via the German Suchfunktion I fully understand,- but why are you lazy slacker not using it???