76 possible electrical problem

[240260280z]

SteveJ, first of all I would like to thank you for staying with this issue.

Steve is a great guy and one of the electrical experts on the forum.... we are all lucky to have him.

[SteveJ]

Steve is a great guy and one of the electrical experts on the forum.... we are all lucky to have him.

Until I start reverting to my curmudgeonly attitude.

Thanks for the compliment, Phil.

Of course, in this case, an expert is someone who has made plenty of mistakes and has learned enough from them that the frequency of repeating said mistakes has dropped significantly.

[beermanpete]

Last thing before installing the new regulator and this may be stupid. Is it possible that I have a internally regulated alternator hooked up to a external voltage regulator? Can you tell by looking at the alternator? I assume that this may cause issues.

Just want to confirm before I get stuck with two voltage regulators. Not a big deal but the $100 could be spent on beer this evening.

Yes, having both regulators will cause your symptoms (as Steve has already said). The only thing I can suggest to look for on the alternator is the terminal markings (if there are any) near the 2-pin connector. The externally regulated alternator has "F" and "N" terminals. The internally regulated alternator has "S" and "L" terminals.

[5thhorsemann]

Correct me if I'm wrong, But if you unplug the external regulator and see 14 VDC at the battery (good thing), then you turn the key off and the car dosn't stop running, you're conclusion would be that there are two rectifiers in play. Then all you would need to do is add the diode to eliminate the problem of not being able to kill the engine. Wouldn't this be correct?

BTW, expert defined; An EX is a has-been, and a SPERT is a drip under pressure. No offence........

[bhermes]

I have a delima, but not positive yet. Supposedly the alternator I replaced in the car is not internally regulated. At least by spec so I am going to try and find someway to determine. I beleive that you guys are telling me that the internal and external regulated alternators can be wired up the same. Obviously in one case you end up with two regulators and a problem.

So if I have an non internal regulated alt then I simply have a bad voltage regulator.

If I found out the spec on the alternator is incorrect and I have an internal regulated alt then I need to get the bypass connector etc. and modify the wiring to bypass the external alternator with a few other issues to check and be concerned about.

I know that the alt came from Oreilly's Auto and is remanufactured.

[5thhorsemann]

If you have the ZX internally regulated alternator, all you need to do is get the MSA regulator eliminator plug and connect it where the regulator plugs in. No wiring changes are required, just follow the directions from MSA. This whole upgrade takes like 15 minuts to complete, spend the few bucks and you are done, well worth it.

We are on post #54 here, should have had this whipped by post #3. Remember, your time is worth money, and you have wasted alot of your time trying to re-do that which has been done many times.

Edited March 4, 2012 by 5thhorsemann

[bhermes]

I agree with you completely but the issue here is that the alternator was not supposed to be internally regulated and now I beleive it is. The marking that I can read are "S" and "A". I checked the voltage at the battery one last time and got about 11.6V at all rpms (idle - 3000rpms).

Ordering plug and I am out.

Thanks for all the help and education.

[Zed Head]

If you have the ZX internally regulated alternator, all you need to do is get the MSA regulator eliminator plug and connect it where the regulator plugs in....

bhermes has a 76. The plug is designed for 70-73. I don't think that it will work as a simple plug-in and go fix.

The externally regulated alternators appear to be labeled F and N on the T plug. They are also smaller than the internally regulated alternators.

The internally regulated alternators appear to have no letter labels on the T plug, but if they did, there would be an L and an S.

Any auto parts store should have a testing machine that will tell you what kind of alternator you have.

[bhermes]

If you are tired of this post I will understand so ignore.

I just dont see the issue with unplugging the external voltage regulator and running off the alt. inernal regulator with no other changes. For anyone that is an electrical expert here chim in.

I am sure I am missing something but not sure what.

Otherwise I need to search around for a fix if the 240 fix will not work.

Again, if tired of the post ignore and move on.

[5thhorsemann]

bhermes has a 76. The plug is designed for 70-73. I don't think that it will work as a simple plug-in and go fix.

The externally regulated alternators appear to be labeled F and N on the T plug. They are also smaller than the internally regulated alternators.

The internally regulated alternators appear to have no letter labels on the T plug, but if they did, there would be an L and an S.

Any auto parts store should have a testing machine that will tell you what kind of alternator you have.

After all this I had forgotten about the 76 part, the MSA plug only works with pre 73 cars, my bad.

Back to having the alternator tested, and getting the right replacement part(s).

[beermanpete]

I have a delima, but not positive yet. Supposedly the alternator I replaced in the car is not internally regulated. At least by spec so I am going to try and find someway to determine. I beleive that you guys are telling me that the internal and external regulated alternators can be wired up the same. Obviously in one case you end up with two regulators and a problem.

So if I have an non internal regulated alt then I simply have a bad voltage regulator.

If I found out the spec on the alternator is incorrect and I have an internal regulated alt then I need to get the bypass connector etc. and modify the wiring to bypass the external alternator with a few other issues to check and be concerned about.

I know that the alt came from Oreilly's Auto and is remanufactured.

Try this to determine which alternator you have:

With everything connected normally, start the engine, turn on the headlights (to load the alternator) and verify the output voltage is 14 or higher. Now unplug the 2-pin connector on the back of the alternator. If the battery voltage stays at 14 or higher you have the internal regulator. If the voltage falls to 12 or so then you do not.

[bhermes]

Will try the suggestion tomorrow. However, when I unplugged the external regulator and checked battery voltage and got the following;

1000 rpms - 11.6V

1500 rpms - 11.6V

2000 rpms - 11.6V

I thought this may mean that I have a internal voltage regulated alternator. A previous post stated that the alt output was proportional to the rpms.

When the external was plugged in I got the voltages changing with rpms and ranging from 14V to 18V.

Again I will try the suggestion to have additional data.