Can anyone please explain to me how the tachometer on the 1.3 carburetor engine works?

I want to run a standalone ECU for the ignition and keep the original tachometer, but I don't know what kind of signal I should give it.

I have specialised tools like multimeters and an osciloscope.

 

The only thing I can assume at the moment is that it gets a spike voltage from the primary coil winding once every 1/2 engine rotations.

Since I am the only one that reverse engineered the dashboards of all Felicia cars, here is the schematic for the tachometer on carburetor cars.

Basically the input pulse from the ignition coil is filtered and shaped more or less to a TTL signal then fed to a proprietary IC dedicated for tachometers.

That IC then drives the two coils of the tachometer.

 

On 18/04/2020 at 20:56, RicardoM said:

Since I am the only one that reverse engineered the dashboards of all Felicia cars, here is the schematic for the tachometer on carburetor cars.

Basically the input pulse from the ignition coil is filtered and shaped more or less to a TTL signal then fed to a proprietary IC dedicated for tachometers.

That IC then drives the two coils of the tachometer.

 

So if I go dirrectly to pin 13 on the PCB I can give it a square signal and it will make the tacho go?

Yes.

On 18/04/2020 at 20:56, RicardoM said:

Since I am the only one that reverse engineered the dashboards of all Felicia cars, here is the schematic for the tachometer on carburetor cars.

Basically the input pulse from the ignition coil is filtered and shaped more or less to a TTL signal then fed to a proprietary IC dedicated for tachometers.

That IC then drives the two coils of the tachometer.

 

 

Great Work !!!
I just would like to know if the favorit use the same system for the Tachometer ? 

No.