Tachometer acts Sticky

[PaulRandall]

I have a 1980 Fiat 2000 Spider which came with 2 tachometers. Both have the same problem which is that they don't accurately show the RPMs and that the movement of the pointer seems like it is sticky. Today I started the motor and the tach reved up to about 2500 then i let it idle, probably around 850 RPM, but the tach only went down to 1500RPM .
Anybody have any ideas?
Thanks,
Paul

[18Fiatsandcounting]

Do you have an aftermarket ignition system? The Veglia tachometers had occasional issues with the electronic ignition used in 1979 and newer spiders, often made worse by aftermarket additions. One fix that is often done is a capacitor inserted in series in the tach pickup line from the coil. A brown/white wire I believe.

I suppose both tachs could be bad but that's unlikely.

-Bryan

[PaulRandall]

Thanks Bryan,

Thanks for your reply. I not sure what an "aftermarket" system would be. I did put a new distributor in from Autoricambi. The coil and ignition module are what came with the car and look original or equivalent. There is what I think is a capacitor mounted next to the coil, with the wire going to one side of the coil. that says "autovox" on it which I think reduces radio interference.

Do you know the specific capacitor?

Thanks,
Paul

[18Fiatsandcounting]

If you search this forum for "tachometer capacitor" you'll find references to such a capacitor. 0.68 uF (microfarads) with a 400 volt rating appears to be what you want. The exact capacitance doesn't matter, but the voltage rating should be high enough. Any electronics shop should have these or you can order it online for pretty cheap.

-Bryan

[PaulRandall]

Thanks for your help again!

[Jallajalla]

I have experienced this om my 81, - many years ago. Yes, it was sticky. The indicator were like soaked in a sticky mess and would not show actual rpm or fall back to rest in time. I just bought a small aftermarket tacho and built the electronics into the original housing. Just lifted the indicator and dial over. Looks like original, - had to put parts of it (new one) on the outer backside of the original housing.

I tried to clean the original internals but gave up.