Hi All,
"full charged" battery doesn't mean it will still deliver what it used to, that component wears and need replacement, this is absolutely normal.
Less normal is the earthing issue. Seems like the cables Fiat uses for earthing is prone to oxydation resulting in "powdering" itself inside the insulation so you won't even see it. As a result, the usable section is reduced so its resistance increases (resistance is proportionnal to length and reverse-proportionnal to section, at least to a certain extend called peal-effect). Since the starter motor (even its relay) pulls a lot of Amps out the battery, the voltage drop through this earthing cable can be so high that the pinion doesn't fully engage on the flywheel, giving the nice embarrasing grinding noise...
To verify that cable, shunt it with a high section (7awg) jumper cable clamped from battery NEGATIVE to the gearbox.
- If its starts ok, the earthing cable is probably bad or has bad connections -> fix/replace.
- If not starting ok, the battery is probably dying -> try to connect a running car to it using jumpers cables: if ok replace your battery.
- If none of the above works you need more investigation: worn pinion, worn flywheel gear, dying starter, lack of lube, ...
Regards, Bernie
If someone helped you fix or understand your issue here, hit the thanks button, it's free !!