I've got a 6'000 RPM VDO tach and when I wired it up to my van (t25 but I dont think that will make a difference, eventually going in my 12v bug) I found that although it works, the actuall reading is really low, about half the rpm it should be?
![Huh](http://cal-look.no/lounge/Smileys/default/huh.gif)
It does go up and down with the engine RPM though.
It deffo a 12v unit, and on the back it has the following codes etc
230/13/10
12v
24000
I wired it up with a 12v feed to the '12v' post, the negative side of the coil to the '1' post, and earthed the '-' post.
Any ideas whats up with it? Do i need some sort of intermediate unit?
For refrence it will be used with a MSD system with a reading taken off the blaster coil, although tested on stock t25 coil.
Cheers in advance.
![Smiley](http://cal-look.no/lounge/Smileys/default/smiley.gif)
Dude
![Cool](http://cal-look.no/lounge/Smileys/default/cool.gif)
![](http://i89.photobucket.com/albums/k228/deanodynosaurs/VDOTacho2.jpg)
![](http://i89.photobucket.com/albums/k228/deanodynosaurs/VDOTacho3.jpg)
![](http://i89.photobucket.com/albums/k228/deanodynosaurs/VDOTacho4.jpg)