70 chevelle
Volt Reg

Finally got my car to fire over the weekend, but ran into a snag. The alt is not charging the battery. I get roughly 12.4 volts coming out at the battery. When we disconnect the + cable from the battery, the car dies.

The alt is brand new, I even took it back off and had it tested and it tested fine (output on bench was ~15 volts)

Here is how it is wired, Blue wire from alt is going to F on volt reg. Black wire on Alt is going to terminal 2 on volt reg. Terminals 3 and 4 are spliced together and run to GEN Gauge in Dash. Red Alt back to fuse box and out as red solenoid power to junction block and then to + cable. +cable then runs to starter.

Is something wired incorrectly???

70 chevelle
Volt Reg

Finally got my car to fire over the weekend, but ran into a snag. The alt is not charging the battery. I get roughly 12.4 volts coming out at the battery. When we disconnect the + cable from the battery, the car dies.

The alt is brand new, I even took it back off and had it tested and it tested fine (output on bench was ~15 volts)
First, you should NEVER pull a battery cable when the engine is running as it can blow the diodes in the alternator.

Here is how it is wired, Blue wire from alt is going to F on volt reg. Black wire on Alt is going to terminal 2 on volt reg. Terminals 3 and 4 are spliced together and run to GEN Gauge in Dash. Red Alt back to fuse box and out as red solenoid power to junction block and then to + cable. +cable then runs to starter.
Does the GEN light come on at all????
Is something wired incorrectly???

That would be my first guess. See pic for correct wiring.

http://www.chevelles.com/showroom/data/500/new_alternator_wiring_pic2.JPG

yes Gen light comes on when I turn the key on, and now that there is a little drain on the battery it is now on. The first few times when the batt was at full charge it was off, but now it is on every time I start the car.

If your wiring is original factory wiring, look closely at the wires at/on the alternator and regulator connectors. Verify one hasn't broken off the terminal. Remove and clean with a wire brush.

The regulator may be bad. i understand there are some points in there that can be filed? It might not hurt to buy a new one anyway for reliability purposes.

Steve

If you replace the regulator, get the solid state replacement. MUCH cheaper and more reliable. It doesn't "look" original, but they work great. And, be certain that the case of the regulator is grounded and that you have good continuity between the radiator support and 'engine' ground.

The alt is not charging the battery. I get roughly 12.4 volts coming out at the battery. When we disconnect the + cable from the battery, the car dies.
12.4 open-circuit volts means the battery is already about 1/4 discharged. You should expect the battery to be producing 12.6--12.7 ocv.

You've already been told about disconnecting the battery cables when the vehicle is running. A second reason is that the spark produced can ignite hydrogen gas from the battery; you don't need to re-discover the Hindenburg under your hood.

Here is how it is wired, Blue wire from alt is going to F on volt reg. Black wire on Alt is going to terminal 2 on volt reg.
Depending on what terminals those wires are plugged into at the alternator, that is correct.
Terminals 3 and 4 are spliced together
Wrong. 3 should be a fairly heavy red wire, it supplies voltage and some current to the regulator so the regulator can sense the system voltage.

and run to GEN Gauge in Dash.
That should be ONLY the (usually brown) wire from terminal #4. Do you have a gauge or a light?

Red Alt back to fuse box and out as red solenoid power to junction block and then to + cable. +cable then runs to starter.
Not what I'd expect. What is "red solenoid power"?



http://www.chevelles.com/showroom/data/500/new_alternator_wiring_pic2.JPG

Be VERY CAREFUL with that diagram. It is NOT CORRECT, and the mistake is copied in literature all over the internet. So far as I can trace, the original mistake was made by MAD Electrical.

They have reversed the wire connections at the alternator 1 and 2 terminals. The wire from the "F" terminal of the regulator connector SHOULD be connected to the terminal labeled "2" at the alternator. (usually a blue wire) The wire from the #2 terminal of the regulator connector SHOULD be connected to the alternator terminal labeled "1". (a black, black w/ white tracer, or white wire--depending on year and model.)

Given any kind of choice, I'd pitch the alternator and the regulator in the scrap bin, and convert the car to a 12SI internally-regulated unit. A 10SI would be nearly as good. If that's something you'd be interested in, use THIS diagram:

http://www.chevelles.com/showroom/data/500/medium/Alternator_wiring_harness_conversion.GIF

OK, so everything is wired correctly, I've tried 2 external voltage regulators (the newer solid state ones) and 2 alternators, and still not charge. Could it still be the voltage regulator? I have a 63 amp alt, are there different regulators for different amperages? I am ready to pull my hair out. This may be a stupid question, but when looking at the engine from the front of the car, which direction does the alternator turn? Are there different alternators (direction that they need to spin in order to charge)? Anyhow, anything at this point may help me out.

First, Im a little confused :confused: Are we dealing with externally (which is original foe the car) or internally regulated alternator?

Forget the regulator for a moment. Let's full-field the alternator.

Disconnect the external regulator connector from the regulator.

Start the engine, run at fast idle.

Jump the "F" and "3" terminals of the regulator connector with a short wire. About ten seconds will be PLENTY long enough.

The alternator better produce high voltage and high amperage. (It'll hum like mad, and the lights will get REALLY BRIGHT.)

IF it does, the alternator 'n' harness are good. You most likely have a defective voltage regulator; or a bad ground on the regulator.

If it does not, the alternator or the harness are defective--now you get to verify that you have battery voltage at the #3 position of the regulator harness; and you get to verify continuity of the wire connected to the "F" terminal all the way to the alternator #2 (or "F") terminal.

Every automotive/light truck alternator I can think of turns the same direction as the engine's crankshaft.

And, since they generate alternating current (before it gets rectified) it doesn't matter which way they turn...... Lot of times you see one added and flipped on cars with BIG sound systems. Also all the different output alternators use the same regulator.............. It regulates voltage not amperage.

OK, so I have been reading as many old posts on here as I can, maybe????? not sure??? Maybe I have a grounding issue. How exactly do I ground the voltage regulator. Right now it is just mounted to the Rad support. Do I run a ground wire from it some how? There are the four spade terminals for F-4, then there is a spade coming off the side of the regulator, is this a ground? But it looks like it is a spade that is connected to spade F???? This a 15.00 solid state external regulator from NAPA. I have tried 2 from them. I am going to get one from Auto Zone or Advance Auto Parts, but after reading many posts, maybe I don't have it ground properly.

OK, so I have been reading as many old posts on here as I can, maybe????? not sure??? Maybe I have a grounding issue. How exactly do I ground the voltage regulator. Right now it is just mounted to the Rad support. Do I run a ground wire from it some how? There are the four spade terminals for F-4, then there is a spade coming off the side of the regulator, is this a ground? But it looks like it is a spade that is connected to spade F???? This a 15.00 solid state external regulator from NAPA. I have tried 2 from them. I am going to get one from Auto Zone or Advance Auto Parts, but after reading many posts, maybe I don't have it ground properly.

Forget the regulator for a moment. Let's full-field the alternator.


So what happens when you full-field the alternator?

How do you "full field" the alternator?

Read Schurkey's post above - it tells you how.

After you have done the "full field" test above, use an ohm meter and verify that you have less than 0.2 ohms from alternator case to regulator case. This will verify ground.

I have already done that ground test, and it was less than 0.2. Sunday I'll try the full field test.

So everything is wired properly. The gus from EZ wiring that I got the wiring harness from insist it is the voltage regulator. They claim that they see this problem all the time and that it is not uncommon to go through 9-10 regulators until they find one that works. Anyone here of something like this?????

I bought one from NAPA (a solid state one made in China). I brought it back once and tried another, still nothing. Has anyone else ran into this? Should I just bite the bullet and buy one of the old style mechanical ones that cost about $60? Or can someone recommend another place to buy from (Advance Atuo Parts or Autozone)?

Maybe they are right and I just have to keep trying other reg's.

Anyone???

So what happens when you full-field the alternator?
???

Nothing happens, no increase in voltage. I've had the alt tested and it says good. All wires are correct, grounds are correct, all wires have continuity. I am debating going to an internally regulated alt and trying that.

Ryan, I know you have been working on this for awhile now, keep plugging away, you will get it solved.

What is the voltage reading at the back of the alternator itself, where the main red wire is connected, if the car is running?????

Nothing happens, no increase in voltage. I've had the alt tested and it says good. All wires are correct, grounds are correct, all wires have continuity. I am debating going to an internally regulated alt and trying that.
IF you have performed the full-field test correctly, and there is no increase in voltage, AND all wires have continuity and are routed correctly--the alternator HAS to be defective.

Since you're claiming that the alternator has tested "good" off-the-car, clearly something else is defective and the full-field test is not producing reliable results.

Did you fix the wiring at terminals 3 and 4 at the external regulator connector? Your original description has them spliced together, that is NOT correct.

Yes, I would (and have) converted external regulated charging systems to internally-regulated alternators. Highly recommended.

I just came from havin gthe alt tested by a second place and yes it tests good. I have been on the phone with EZ Wiring several times and they claim everything is wired 100% correct. In their wiring diagram they call for F on the alt to F on reg, R(2) to 2 on reg, the post on the alt for Battery is a red wire that goes back to the fues box and is then routed to the junction block as another read wire. The junction block is then linked to the +terminal. The 3 and 4 terminals on the reg are spliced together and run to one side of the generator light, the other side of the generator light is a whit wire (EZ wiring calls it the alt excitor) and it goes back to the fusebox. They say they have been doing this for over 15 years and it is correct. They insist it is the volt regulator and that it is typical to go through 9-10 till you find one that works. The guys at NAPA and Advance Auto say they have never heard of volt reg's being bad.

Now I know the original wiring for chevelle, has post 3 going to the battery and 4 going to the light. I tried this configuration by running some temp wires and it doesn't work either.

If you give me your email address I can email you their wiring diagram. Also, has anyone used painless wiring and can they send me the painless wiring diagram so I can compare and see how they do it.

I guess if I can't figure this out I will try the internally regulated alt and see if that works. Or should I just do a one-wire and forget it all together?

Guys I really appreciate your help, please understand I am frustrated, so if I seem a little short or ticked off, it is not at you.

OK, so I found the installation for the Painless kits on their website (http://www.painlessperformance.com/Manuals/90552Manual.pdf) Anyhow, look at page 6 and they also show terminals 3 and 4 spliced. I am going to call them tomorrow and see if they have any insight. Has anyone else used either Painless or EZ wiring kits? If so, I would like to talk to you and see if you had any problems or to confirm how you have routed wires. The only other thing is grounding. They indicate in bold not to rely on motor mounts to ground the engine to the frame. Maybe I need to add a ground strap??? My fram is powder coated and maybe a bad ground. However, when I check continuity from the alt to the -post, I get good continuity.

If I add grounds, where do I put them?

OK guys, I want to apologize for not taking yor advice sooner. 3 and 4 should NOT be spliced. I called Painless today since the EZ wiring guys were persistant they were right. ANyhow, 3 and 4 get spliced if you are NOT running any gauges or lights. I ran a new wire from BATT to terminal 3 and from 4 to the light (Painless emailed me a schematic). I had to get a new Volt Reg because I think having it wired wrong, kept blowing it up. Anyhow, got a new regulator, wired it the way Painless indicated and how you guys said it should be and POOF!!!!! It works, thanks a million guys!

Thanks for posting the results. So many don't................. Glad its working!!!!