Boas. No cinquecento 900 do meu irmao instalamos manómetros de sport. Alguém sabe como por o conta-rotações a funcionar? 
Mais concretamente:
"The easiest way to do this is using the ECU feed for the rev counter. this will compensate for the twin coil problem(not very early 94/95 cinqs may not have this wire so check before buying anything!)
the wire you are looking for is a black & violet wire
this comes from the ECU(pin no.23) and is a thin wire which you should be able to find on the fuel pump relay near the brake master cylinder.
if you test this wire on a multimeter it should rear approx 1.6v @ idle and 3.4v @ 4000 RPM
so connect a wire to the black & violet cable and feed it into the dash clocks area.
to keep your gearing right on an 899cc you should swap the actual Speedo over to the new sporting pod. also keeps your mileage correct. You will need to connect the signal wire to the rev counter, this can be done by either soldering a connection direct to the dash clocks as I have done or splicing in a sporting wiring loom connector. a bullet connector will ease removal/refitting if ever needed.
Make provisions for the rev counter signal cable to run through to the engine bay, you will most likely be able to get this in the engine bay via the speedo cable grommet.
Find a suitable path for the cable to run, the signal wire will need to run from the fuel pump relay just behind the MAP sensor to the dashboard, fit a fuse in case of accidents, a fuse of 500 MA will suffice.
You will need to connect in to the Black/Violet wire on the fuel pump relay, its the thinnest wire on the relay closest to the MAP sensor.
After double checking your wiring and securing all new cables, you should have a working rev counter...."
Fotos em anexo.(extrato de artigo de um forum Fiatista do U.k.)
Lamento o atrazo da resposta e.....espero ter ajudado.
Luis
