[euro911sc]

Before you say get a new alternator... I did... and I had the old one rebuilt... same problem. So...

• Battery is an Optima Red. I can charge the battery up and the car runs like a champ: 2 days at homestead running 30 m sessions while charging the car between sessions yielded FUN FUN FUN
• I took the old alternator to an alternator shop. Called back a few days later and the old timer said he saw immediately what the issue was and fixed it. Put it in and system doesn't charge.
• Spoke to a top line mechanic, Klub Sport, he mentioned that 'those' alternators are iffy at best to repair. Bought a NEW alternator, Valeo. Installed. No charging.
• I have checked all the major grounds in the car.
• The charging warning light does not come on.
• Loss of charging seemed to be instant and not a slow decline over time.

How I test the charging system: Charge the battery, measure/note voltage across battery (12.49), start car, measure voltage (11.95), turn high beams on, measure voltage over time... ie: watch the voltage decrease real-time (it dropped to 9.3 in a few minutes before I shut the car off)


I have pulled out the electrical diagram and the systems seems very simple as far as the battery/alternator is concerned. There is a Red/10 wire that goes from B+ to the starter at the same terminal as the big honkin' Blk/25 cable from the battery. I believe this is how the alternator charges up the battery.


My trouble shooting ideas:

1. Since the car will run and start just fine with a charged battery the issue must be in the wire from the alternator to the starter? This would be part of the wiring harness on the engine.
2. I can test the voltage coming out of the alternator if I follow the other Red/2,5 wire from B+ that goes to Fuse 24/25A that leads to the rear defogger relay. This fuse is on the rear panel. Which of the 3 is it? top or bottom one? If this voltage says 14v then that will confirm that the alternator is working properly, no? If it says 0v what then?
3. Is it possible that the battery cable is done? Ie: the battery has enough CCA (800+) to start the car, but the alternator at a meager 75A cannot overcome the resistance to charge the battery? This is a long shot given the sudden loss of charge ability.

This is a bummer since I was supposed to be at Sebring for the whole weekend...


Ideas? Thanks for your help in advance!


-Michael