TJefferson2020

I just replaced my alternator with a new 3 wire, 100 amp unit. Today I took her for a test drive and when I returned my battery (optima red top) was totally drained. Battery just checked out fine about two weeks ago (leading me to replace the alternator).

On a side note, I'm punching myself in the ***** while I'm writing this. Getting tired of sudden electrical weirdness.

The alternator has two connections - "F" and "the other one". Since my harness is custom I don't have the "only fits one way" connector.

I took a multimeter and checked the resistance of each connector to ground. One was 4.6 ohms and the other didn't go to ground.

I believe the one that gave a reading (apparently anything over 2.5 or so is fine) is "F".

I also installed a solid state external regulator. Wiring going to it is to spec.

I may have had them hooked up backwards before. Does this sound (punch) right? (punch).

Avispa

Disconnect the harness from the alternator and the regulator. Check these with an ohmmeter or self powered test light: the F terminal on the alternator plug should have conductivity to the lefthand most terminal on the regulator plug. "The other one" (the R terminal) on the alternator plug should have conductivity to the terminal next to the lefthandmost terminal on the regulator plug.

MiguelsC2

Make sure your regulator is grounded properly.

TJefferson2020

Thanks - I should have mentioned that my stupid alternator isn't labeled. But this does help me confirm everything is in the right place.

I read that nothing bad will happen if you reverse these wires - just your battery won't charge. I've got it on a charger tonight and I'm going to run it tomorrow and see what happens.

My voltmeter (ammeter is in a box) reads 14+V when running - but apparently it wasn't going to the battery although I can't imagine how it wouldn't....

buns

Here is a wiring diagram for the alternator and regulator.

TJefferson2020

Looks like I managed to kill my Red Top Optima (ouch). Won't take a charge - can't even work up enough amperage to engage starter solenoid.

Although, I think I do have the wiring right. But between my old alternator and the possible wire reversing my battery has had it.

Oh, well. What's another $178?

5thvet

Have you seen the threads on how to charge a completely discharged optima? You kind of have to indirectly charge it with some of the new trickle charges. Look on YouTube for the video from Optima. You may be able to save it.
Don

5thvet

Here's the link...
http://www.youtube.com/watch?v=Slqd7...eature=related

TJefferson2020

Thanks! That's good to know. Just got back from OReilly's and the battery tested fine.

So now I'm stumped.

Is there any way a new alternator could have killed my starter? I have one of those mini high torque starters. It just clicks like it's not getting enough power. Checked my maxi fuse (Painless wiring system) and it's fine.

Never had any electrical issues before - only thing different is new alternator. What the hell?

5thvet

Have you checked all the connections at the starter/solenoid/battery cables? Tried giving the starter a whack with a hammer?

John S 1961

Research a little at Madelectrical.com, or call them if you can get them, as I recall the hot power lead from the alt needs to run direct to the amp meter (I suggest shunting, jumper across the back) and then your electrical system will get power the way it used to.

TJefferson2020

I'll give that a go over in the morning.

I have a volt meter (autometer unit). It reads 12+ volts and 14V when running. Not sure if that matters. I will call them and see if they have some ideas. I will also call back the alternator manufacturer and see if they have any insight.

Here's what I don't understand. I wired it exactly like my previous alternator. The only difference is that my new alt doesn't have a ground post - it grounds through the case. I checked it with a multi-meter and it's grounded.

The other weird thing is that I started it up about 4X with this new configuration and it ran/started fine. All of a sudden, after a test run, I shut it down and when I went to restart - it was dead.

All I did was swap out the alternator. Nothing else changed. Never had a charging problem or starting problem before.

Once I get the battery back in, I'm going to test the voltage at the starter when cranking. I'll also check to make sure the starter isn't shorted.

Another strange issue with this is that the system intermittently is totally dead when turning the key - no voltage at the gauges, no clicking, nothing.

A few minutes later, the volt gauge is back and the starter clicks like a dead battery.

Jeez. I just needed a new alternator. What a hassle.

TJefferson2020

Here's something I found in the manual for the wiring system:



Apparently, installing a higher voltage alternator requires modified wiring - although it seems that the external regulator has disappeared. I'm guessing that wiring is the same - just eliminated from this drawing (shows a later model GM alternator with internal regulation).

Now I'm really confused. I'll call painless to check.

5thvet

"Another strange issue with this is that the system intermittently is totally dead when turning the key - no voltage at the gauges, no clicking, nothing."

Have you checked the firewall side wire connector with the infamous big red wire?
Don

plaidside

You might have two things going on. One is a charging problem and the other might be a connection problem at the firewall.
You stated that there was no ground terminal on the alternator. I am not that fimiliar with mid years but doesn't the ground for the regulator connect to the housing of the alternator?
Use this paper I wrote to understand and check your system.
Can you post a picture of the alternator installed?
Joe

http://temp.corvetteforum.net/classi...ternator.shtml

TJefferson2020

Dang - I'm sorry. I forgot to tell you that the infamous firewall connectors are gone - my wiring system has a bundle of wires through a grommet right into a modern GM fuse box.

In my case, the regulator grounds from a tab on the side of the regulator to the bolt holding it to the radiator mount. The Alternator has a dedicated ground wire, but my new alternator doesn't have a post for it. The mfg says it grounds through the case.

Photos coming.

Thank you all for your help - I'm still digging for answers with various mfg's - Painless, TuffStuff (alternator), and powermaster (starter).

TJefferson2020

Mystery solved. Thank you all for your suggestions- very helpful as usual.

Turns out it was a combination of things - loose engine ground, deteriorated (+) battery cable (only lasted 2 years!). Plus, I found out that when you go to a high power alternator, Painless requires an extra 8 gauge wire from the positive terminal on the alt to the maxi-fuse. This prevents the main wire from burning up.

I also increased my battery cables to 4 gauge and installed a solid state regulator.