New Alternator No recharge

[Mr.P 911T 1970]

Pelicans,

Replaced original alternator with new Valeo 55amp alternator, replaced and cleaned all grounding straps and connection points, recharged both batteries to full (12.3v), and replaced all battery connections, however, I have no recharge at ANY RPM.

When I insert and turn the key, Generator light is ON and once the car is at idle (takes a bit of massaging), G-light is off (or very very faint). Regardless, meter reads no charge (supposed to be 14.5v @2000 RPM).

Any ideas?

Thanks

[timmy2]

Did you replace the Voltage regulator?
Year of car, internal or external VR?
I’m guessing it is a 1970?
Is the new alternator internal or external VR?

[Mr.P 911T 1970]

Thanks for the quick reply. It's a 1970 911T. I did not replace the VR.

I ordered the Valeo alternator and assumed it had a internal alternator. It came with this note

"When replacing original alternator, Refer to Technical Bulletin group 27 #82-02 2/12/82/ Remove External V/Reg Models w/External V/Reg, Cut and disconnect DF (Field Wire) from Wiring Harness, Connect Blue Wire to Terminal 61, Connect Brown Ground Wires to D- Terminal, Connect Red Wire to B+ terminal. May require the addition of a second ground wire from Engine to D- Terminal."

I did just that. Now, I have the black wire wrapped up, secured outside of the fan housing not connected to anything.

[Mr.P 911T 1970]

Valeo alternator. P/N #17012-01085582

After researching other threads, all said the same thing - don't connect the black wire and just secure it.

[john walker's workshop]

And remove the old regulator.

[timmy2]

And add a 91 ohm 5 watt resistor across the lamp terminals like the Porsche bulletin specifies?

[timmy2]

Resistor part # from Mouser:

[timmy2]

Bulletin referencing NLA resistor posted here:
1982 911SC Alternator

[Mr.P 911T 1970]

Old VR removed and still no recharge to the batteries at any RPM.

I did not include the 91 ohm 5 watt resistor across the lamp terminals. I checked with Mouser, looks like a long lead time (10 weeks).

I can live with the faint G-light as long I know that the batteries are recharging and the alternator is doing its job.

1. Does anyone know where I can locate one?Alternator light doesn't go out after startup

[timmy2]

I have a few. I’m assuming you are in the US?
Do you just want the resistor or what is in the photo?
PM or email me.

[Mr.P 911T 1970]

[Mr.P 911T 1970]

Here you can see I have the correct hookups: Red -> B+ (3 o'clock), Blue -> +61 (6 o'clock), Brown -> D (9 o'clock).

I also noticed the other day at the starter a yellow loose wire. Would that have an effect?

[timmy2]

Loose yellow, no, no effect on charging.

[Mr.P 911T 1970]

Well, I think I figured it out.

I installed the high torque starter about 1 week prior to the car dying on me. When I installed the starter, I had the black battery cable connected and the yellow wire, however, when I asked an "expert" about the red wire, he said it was an "auxiliary" and not needed.


I went back to the starter and found the red "auxiliary" wire just hanging loosely...AKA, "The wire which is connected from the back of your alternator (B+) and charges your battery, via the black wire on your starter and sits on the same stud". SEE The lone black wire from the starter to the battery on the diagram.

I'll let you know how it goes tomorrow. BTW, the alternator connections were correct but its good practice putting everything back together again.

See the wire diagram which is much better than the books.

[timmy2]

Yes, connecting the alternator main output to the cable that runs to the battery is important...
Find a different “expert”...

[Mr.P 911T 1970]

Alright Folks, consider this post CLOSED for now. Update:

What I had suspected and Dennis confirmed, was the case. The red wire from the alternator to the starter needs to be connect along with the black.

I did not have a 14.5v recharge at @2000 RPMs, I had 13.8ish - acceptable because the batteries (yes, still have two) were already around 12.2v.

Thanks everyone!

[911obgyn]

Voltage at batteries will be less than alternator output because of voltage drop, also regulator.