3volt coil?
do you mean a 3 Ohm


12.1 volt battery is no good, imo
12V is considered a "flat" battery
A good battery is 12.6V and holds 12.6V

Charge it fully for a few hours, and it should be over 12.6 V
leave it overnight connected to the car and it should be the same, 12.6.......if it drops to 12.1 V overnight its past its sell by date.

Also test cranking voltage: with a fully charged battery (12.6V), crank the starter with your voltmeter on the battery........what does it read?

 

Thx Dom, will do. The battery is only a year old so hoping it’s not gone. I’ll let you know how it goes.

 

reading 10,3V after 3-4 seconds cranking sure sounds like a bad battery to me.

a year old battery should still have a guarentee (if you bought it at a shop)

do you have a modern car in the household where you could jump and test the starter that way? (not some old battery lying around in the garage, that too might be dud!)

 

Sorry, fat fingers. 10.3 should have read 12.3, e.g. after cranking and then stopping the new reading of the battery was that it had 12.3v rather than the 12.75v it had before cranking.

 

So when you jump it from another battery it starts OK? - battery is fubar by my reckoning, a decent motor factor should be able to stress test it

 

That battery is dead.

 

if you still have slow cranking (with a good battery), then you need to check a few basics before condemming the starter motor
make sure battery ground is clean, wherever that is bolted to on your car...
make sure your battery poles are clean...check that the cables are not going greenish in any way
then the main live from the battery at the starter....dirty connections on the starter itself can eat up cranking ability.

It could of course be the ignition switch contacts....a starter relay is a good addition to save an expensive ignition switch
(not sure if your coupe has that already or not.......sort of doubt it, knowing alfa)

 

Whilst you crank the starter, you can expect a reading less than 10V on a meter across the battery terminals, thats the cranking volts, but it should recover quite quickly to its charged reading, so if it does not recover from 12.3 volts to nearer 12.6v there is something wrong with the battery. It might be able to be rescued using something like a Cetek charger on a long slow charge, I think there is a 'repair' mode. Mine is in the garage, I will look later.

 

When you say it should recover, do you mean with driving? I assume it would not recover from 12.3 to 12.6+ without either driving or slow charging? When I tried again today the battery started at 12.8 but ran down to 12.3 after a number of tries starting the car.

 

Thanks everyone. I hooked the car up to the battery in my X5 (ignition on, engine not started) and this did not improve the cranking, when I started the X5 up this gave it enough to turn over properly, so to me this feels like it’s not necessarily the battery. I will clean everything up over the next few days and see if that makes a difference.

 

Certainly, bad earths are often a problem. Put a multi meter between the Neg on the battery and if you can the starter motor body, if not, just the engine block, you should get a very low reading, 1 -2 ohms.

 

Multimeters are not my strong suit (among many weaknesses), I set the meter on 2k ohms and get a reading of 0.05 if I do as you say, both to engine block and starter body. Additionally I’ve taken the earth strap off and it looks in really poor condition so I’m going to order a new one. I’ve also tried the battery again and after 24 hours charge and a good many turnovers this morning it’s reading 12.75v this afternoon so I’m pretty sure it’s not that.

 

that earth strap has had it!

 

Earth strap replaced, starter motor troubles gone! Now starts first time with the aid of the new distributor as well.