[67Dan]

What a day! Bought another regulator, Delco this time to replace the Standard on my 67 GTO. When the engine is in drive and running at 700 RPM’s it will buzz loud. Seemed to be when the engine was warm with the Standard! The Delco is consistently doing it! In park the engine is running from 1100 to 1000 RPM's and no buzzing! Talk about drive me crazy! The voltage is running close to 14.5 volts! I also checked the number three post and the voltage recorded is the same!

I plan on checking again tomorrow with a stethoscope to make sure it’s the regulator, but I’m sure it is!

Something tells me the alternator has to be causing the problem! The voltage drops a bit when stopped in drive and I have the brake on and it is at 700 RPM’s or less! In park no problem, but higher RPM’s! Could the diodes be out, brushes, windings! Is the moon made of cream cheese! I’m out of ideas and I’m going crazy!

George I need some help! I also have some sound clips on Photo bucket if that helps and or you are interested in listening!

My email is dmascheck@sbcglobal.net or call 979-533-0207 mobile or 979-532-2371 office

Dan Mascheck
Wharton, TX

[Old Goat 67]

Here is the link to your video Dan.

http://s1211.photobucket.com/albums/...t=IMG_1386.mp4

http://s1211.photobucket.com/albums/...t=IMG_1385.mp4

http://s1211.photobucket.com/albums/...t=IMG_1384.mp4

[67Dan]

Thanks!

[guccieng]

sounds like the key buzzer that's supposed to go off when the key is in and the driver's door is open. are the courtesy lights coming on, too? they are connected to the same switch in the driver's door jamb. is the pink/black wire from the ignition switch to the right lug on the relay shorting out?

[Old Goat 67]

No key buzzer on 67's.

[67Dan]

Listen to the sound!

Has to be a problem with teh alternator causing the problem!

One thing I will try today is checking the voltage with the AC and lights on and see how much drop I get! It only happens at low idle around 700 RPM's or less!

[67Dan]

OOPS! Not link!

Here it is!

http://s1211.photobucket.com/albums/...t=IMG_1384.mp4

[george kujanski]

I've got to say, that's the worst I've ever heard.

As mentioned B4, the primary cause of regulator buzzing is usually poor regulator body-to-bat negative connection or a poor connection from regulator terminal 3 to the battery positive. Either of these two will cause slow voltage sensing in the regulator and resultant audible buzzing.

Since the reg is new, and several of them do it, electrical connections good, etc. My next suspect is open diode/diodes or bad stator connections in the alt. The alternator is a 3 phase machine, if diodes or a stator connection is open, the output will have more ripple, (fluctuation) and the regulator will be trying to follow the ripple. i would also think the buzzing will change with RPM if the alt has that issue.

The voltage regulation may still be ok, altho have more ripple, which may not be seen on the DC setting of the meter.

Try using the AC volts function measured at the alt output stud, and compare it to a car that does not have this issue. If it's the alt, the measured AC voltage should be higher on the troublesome car.

George

[67Dan]

George,

Thanks for the reply! Your one I really trust! I have a direct ground wire run from the battery to one of the blots that secure the regulator to eliminate that problem. I checked the voltage on my meter and it reads 14.5 volts at the battery and when I try a full load with lights on bright and the AC on it may dip to 14.2. I also checked post 3 on the regulator and it shows the same voltage!

I have used the Standard that the AC guy put on because the unit that was on the car was running 16 volts he told me and he tried one or two others and finally found the one I had on her when I brought her home with the new Vintage AC! When idling at 1000 to 1100 no sound! When I have the brake on and she is in drive at 650 to 700RPM it comes on every time under low idle! Listen to the sound clip and it can be loud! I then changed to a new Delco unit and it's even louder.

Other than some screwy wiring under the dash, I’m at my wits end and the only thing I can come up with is something in the alternator is wrong! If the alternator is causing the problem, what do you recommend to replace it and do you have the number please sir.

Please give me some spiritual advice Electronics God!!(GRIN)


http://s1211.photobucket.com/albums/...t=IMG_1384.mp4

[Old Goat 67]

Thanks George,

Trying to diagnose this thing from 300 miles away kinda had me stumped. I was leaning towards a diode problem also, especially after all the other regulators tried.

Dan, ball's in your court now buddy!

Charles

[67Dan]

George,

Now trying to find one that works in my neighborhood is a problem. You’re saying my output will be higher, but that is relative. If the diode is out, how much higher are you looking at? Two volts? Less? I would have thought there would be another way to check a faulty alternator?

Then to play devil’s advocate, what if that doesn’t do it? Sell the car or dynamite?

Being you are the Delco person. Again let’s carry this one step further, what number Delco alternator do you recomend? Wold moving up to an internally regulated unit be better than one with an external regulator!

Dan Mascheck
Wharton, TX

[george kujanski]

As a final test, set your meter on the AC function, and measure the voltage from the alt terminal 2 to ground it should be around 7 or 8 volts, AC.

Again if diodes or a stator connection is bad, there will be more ripple in the terminal 2 voltage also.

If it is a alt issue, (probable), get a Delco 10SI 62A alt; should be good enuf for your electrical loads. These are readily available from any Pontiac, about '74 on up thru '80 or so. The Pontiac flavor only may differ from other 10SI used by Chevies, etc. in the position of the rear housing, i.e. where the output stud is, otherwise, electrically all 62A 10SI alts are the same. That will be your best bet if the alt is bad, a minor wiring change is required to convert your external reg car to the internal reg alt; probably a 10 min. job. Plenty of advice on the conversion in these forums.

If you have an electric water pump or electric cooling fans, the better choice would be a 12SI from the mid '80's on Camaro and Monte Carlo; up to 94A. Drops right in too.

George

[67Dan]

When you say ripple you mean and up and down voltage variation? How much variance would you expect?

I pray this solves the problem! I have been trying to figure it out for some time! If this is not it, then punt! I have other issues with the car I'm trying to solve as well, but this is one of the most vexing ones! I wish I could buy one with zero problems to solve! Everyone I get there are always Gremlins!

Thanks George and I will try checking when I get hom efrom work!

[67Dan]

George,

Took out two volt meters! One analog and one digital. Checked the main post on back of the alternator and it comes out to 14.2 volts and varies a tiny bit. Then there is a two wire plug and I checked both wires to ground. Here is where it gets interesting! There are two smaller wires coming out of the Alternator! One is blue and the other is black with a white stripe. The black with white stripe ran: 7 and varied a little. The blue wire is the interesting one. It ran from: 6.75 to 9.2 and it floated all over the place!

Another interesting fact is since I idled the engine down a bit, the buzz is consistent when you are around 700 RPM to about 850 to 900 it seems to go away, but below the 700 or 750 hard to tell with my eyes, it goes away. So there is a narrow range where it will happen and then will go away! Is it bad?? I also used an old small analog meter and my digital one. Both showed the same results, but the digital one was more accurate!

For grins I took the car to OReily’s. They have a meter they can hook to the battery. It showed about 14+ volts! 35 amps at idle and the gal said the diodes where good at idle! Of course remember the sweet spot I told you about when the buzzing occurs and I didn’t think about speeding the engine up slightly. They say they have another machine they can test it on, but I have to take the alternator off and they can put it on their machine! Are their meters and or test any good?

Help???? Now what? You are the guru!

Lastly, if you say the unit is bad, I need the part number of the alternator that will fit my 67 GTO and has the right hole pattern and I would like more amps with the electronics I run. I would prefer to stay with Delco and keep the external Delco regulator please.

[LPete]

Dan,

You either have to look at the alternator output with an oscilloscope, or measure the AC voltage at the output. "Ripple" is an alternating current superimposed on the normal DC output -- it's caused by a bad diode or stator winding. You won't see the fluctuation measuring DC voltage -- it's a very rapid fluctuation. The AC voltage should be low -- certainly less than a quarter of a volt.

The fluctuation you're seeing on the blue wire is normal. This is the regulator controlling the field circuit.

I'm not sure if anyone's suggested this, but you could run a jumper wire from the "R" terminal (not the blue wire) at the alternator to the other end of that wire at the regulator (this should at least eliminate a bad wire on that circuit). I doubt if it will help, but it's worth a try.

[george kujanski]

What Lpete said.

As mentioned Before, use the AC volts function of the digital meter and measure the voltage at the alt output. Find another car, any car, and do the same. If your alt has a bad diode or stator, chances are your measured AC voltage will be noticably higher than the other car tested.

As Lpete suggests, connect a jumper wire from the "R" term in the back of the alt to the regulator terminal 2. This will determine if the existing wire in the harness is bad.

If you get another alt and want to keep the external regulator, get one for a Pontiac, say '66 thru about '70, 62 Amp. The Pontiac flavor should have the proper rear housing position. Should take care of your loads unless you have an electric water pump and or electric engine fans.

I don't have part numbers handy for the 10DN alt you are looking for, but the parts store should be able to hook you up. As mentioned, ask for a 10DN alt, 62 Amp for those years; the only difference between any GM application is probably the rear housing position, and maybe the pulley, if it comes with one.

If you decide to go with an internally regulated alt, they were on Pontiac engines from about '73 thru '79. After that, the engines used were Chevies.

George

[67Dan]

I am concerned about the wiring, and to be frank getting tired of messing with the problem. This has been a two month or more ordeal and there seems to be no end in site! Of course I could just change the alternator and be done with it, but then may still have the problem!

You talk about terminals, and for a person that knows enough mechanicing and little about car electronics telling me to check the R terminal to terminal 2 on the regulator is fine, but I have no clue what is the R terminal on the alternator and number 2 on the regulator! I know there is the large post terminal in back, and then there is a plug with two smaller wires. One is blue and one is black with a white stripe. Now, can you tell me which color to hook to on the alternator, and I checked the voltage on the regulator before and it was fine and I think it was a green wire!

Again one foot note is the problem happens at around 700 RPM then subsides after say 800+.

This is driving me crazy! How dependable are the test meters at O’Reily!

A stick of dynamite seems to be the ultimate answer!

I wish there was some one around my area of Texas I could take the car to!

[Old Goat 67]

Dan,

I know you are frustrated, but that won't cure the problem.

If there is not a good alternator starter shop in your area, you will need to find it yourself or enlist help from a local person familiar with these systems.

George is trying to tell you what to check and how, so that you may evaluate what is defective, the terminals he is telling you to check are shown below. This is a page from the shop manual where there is a full description of the system and how it works. Look it up, read it and go forth young man. Lots of info in there, but it just sits there unless you dig it out.

I do believe it is not the regulator causing the problem at this point. Too many units do the same thing. Therefore, the alternator is the likely culprit and if I am not mistaken, the engine harness had been replaced buy the previous owner, so unless the bozo's that assembled the car really screwed something up, it should be good. That only leaves the alternator and you have two choices, replace it and hope for the best OR test it and nail it down so you are sure before spending money.

George is the absolute best at these systems, that's why I keep my mouth shut until he has spoken. Thanks for getting in here George.

Charles

[george kujanski]

OK, then.......there is a two wire plug that goes in to the back of the alt...the letters "R" and "F" should be cast into the rear housing at the plug. The black/white is the "R" (for relay) connection and the blue wire is the "F" (for field) connection.

At the regulator, at the harness plug, you should find the letters F, 2,3,4 molded into the regulator harness connector.

I still suspect the alt being bad since the buzzing is speed and load dependent. More electrical loads would cause more ripple. The regulator being a mechanical device, is too slow to follow the ripple as the speed goes up, and the audible buzzing goes away.

You can certainly just change the alt, a replacement is not expensive from any parts store. In your case, you may very well be tired of dealing with the issue, but doing the troubleshooting first would find the source of the problem rather than end up changing 3 regulators and still not having success.

The choices are: either the reg is bad, alt is bad, or some wiring issue. You seem to indicate the grounds are good, battery voltage is present and solid at terminal 3 of the regulator; and your observed buzzing relative to load and speed supports the notion that there may be increased ripple from the alt, usually due to bad diodes or an open stator winding.

George

[67Dan]

George,

I appreciate the elementary lesson and I really appreciate it!

I got my Wife’s stethoscope to make sure the buzzing is not originating elsewhere! When I hit the magic number of around 700RPM, man it buzzes loud in my ear and upon speeding up goes away EVERY TIME!

I talked to an alternator builder and he said that was the first time he heard of my problem in 35 years! Surprise to me! He talked about pulling the plug on the alternator and seeing if the sound goes away. IT DOES! He also mentioned the old regulators had rubber mounts! The AC Delco and the Standard do not! It is bolted direct to the firewall.

Is there another option of external regulator. Solid state?

I know the ground is good on the regulator. I have tried two personally! The voltage the generator is producing is good, but then the buzzing at a narrow band of operation! I also wonder why the buzzing is not below the 700?? The number 3 location on the regulator shows full voltage.

I measured the voltage on all three points on the Alternator, as you asked, but then you didn’t say what they meant if anything and I did them as you requested!

One last note, is an internally regulated alternator a better solution, or just same old thing? Wanted to keep the car as is if possible!
Next stop a new alternator and prayers!

Dan Mascheck
Wharton, TX