Alfa Romeo Repair: Alfa 164 Electrical Problem, electrical problem, twin spark

Question
I hope you can help me. You are my last hope!

I have an Alfa 164 1993. I live in Ireland. The engine is a 2.0 twin spark.

I was driving 2 mths ago when all the dash lit up and the car stopped dead. cut out. I later found out the battery was dead. re-charged that. It happened again. I then discovered that a small oil leak had destroyed my alternator. So I removed that and got it reconditioned. I have put the fixed alternator back in now but a fully charged battery only last 30 mins before it dies, and then I have to re-charge it up again. I got a new battery for the car but that only extends the 30 mins to 45 mins.

Finally, on further inspection I discovered that there is two black and green strip wires behind the alternator connected to nothing? Is this related?

I don't want to go plugging wires together in case I blow something?

Many thanks for any help you can give me,

Go raibh mile maith agat...

-Robbie


Answer
You really need a digital multi meter to solve this. They can be very inexpensive.  The alternator is not charging enough (I am assuming the red charge light on the dash does go out). If my assumption is correct then it is probable that there is not enough ground from the alternator to the engine block.  This could be confirmed with the multi meter by reading the volts at the battery with the engine running and putting a wire from the body of the alternator to the engine. If the voltage reading increases then that is indeed the problem--other wise the alternator is still defective.
(You did connect the battery wire to the 6mm stud and the violet wire to the spade fitting marked D...).
A fully charged battery will read 12.66 volts and a good alternator will charge the battery with engine running at 13.5 to 14.5 volts.

I do suspect the black/green wires are ground but have no wiring diagrahm to confirm that.