# 1966 Pontiac Star Chief - alternator not charging after replacement of regulator



## Maczuga (Sep 16, 2020)

Hello guys,

I have a common problem tough the details are making me nuts. My mostly stock 66 Pontiac is equipped with the original Delco alternator and voltage regulator (vr). Because I had trouble in fine tuning my 389 cu. in. someone told me once that the fluctuating needle of my ammeter could indicate charging problems that would affect directly engine idling. How true that is remains to me unknown.
Lately I have bought a new vr from a respective Pontiac Parts company for about 50$ - this one is as far the depiction on it tells made in PRC and fully transistorized - so no moving parts at all. It looks like oem, got all four + 1 terminals, that is from looking down to up "F-field", 2, 3 and 4 plus one extra on the backside I don't know use of. Simple instruction that came with it tells to mount it directly as replacement of original...
The factory vr was connected with two wires: light blue connecting F-Fields between alternator and vr, black wire on terminal #3 going somwhere behind the firewall - maybe to the ignition terminal? - This setup worked and still works with giving me fine 14,6 V of charging in idle however the ammeter keeps fluctuating crazy and I don't knowhow it's impact the engine idling.
After installing the new vr the same way nothing works. Ammeter lies dead center, charging not present - battery constantly at about 12 volts, so are the poles +/- on the alternator.
I have looked up the factory wiring scheme and to my surprise there's a vr depicted with all 4 - terminals connected (tough at a closer look my factory electro mechanical has only 3 terminals working (#2 prong is absent).
Looking at this scheme I figured out that maybe I need to rewire the new vr differently to get it working and found that the originally missing #2 prong on the oem vr is present at the new one, so I ran a wire from #2 terminal to the back of the alternator and connected to the "R-relay" slot.
Still nothing happened, the same scenario keeping on, it looks like the alternator is missing it's excitation at engine start.
This is how far I understand this circuit. If any of You is able to help me out I'd be very glad with that.
*The alternator is fused with 30amps.
*I have positive tested for continuity between the base ot the new vr and the alternator cluster - so I guess it should be no ground issue.
*I will note that the oem vr has a spring loaded mechanism with a regulation screw - any need of checking that?
Below I add some pictures of the sight:





































Thanks for replying and greetings from Poland,

Maczuga


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## PontiacJim (Dec 29, 2012)

O52 covered it way better than me. Learned the big cars are different than A-body charging systems. 

Are all big cars wired this way, or just the earlier years?


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## O52 (Jan 27, 2019)

Early big Pontiacs with the ammeter had a three terminal regulator with two wires connected. The Alternator had only two wires, the + battery and a single field wire. With the exception of the big fuse holder behind the alternator, your car appears to be wired correctly. What is the fuse holder connected to?
You need the correct voltage regulator. Look at the part number (1119511) on your old one and do a search on Ebay - USA. They are available as NOS like this one.









NOS Delco Voltage Regulator 1963-1968 Pontiac Bonneville Catalina 2+2 1119511 7C | eBay


Find many great new & used options and get the best deals for NOS Delco Voltage Regulator 1963-1968 Pontiac Bonneville Catalina 2+2 1119511 7C at the best online prices at eBay! Free shipping for many products!



www.ebay.com





Ames also sells a three terminal regulator. You should call Ames to verify that it is the correct one .



Ames Part Detail




I couldn't come up with a 66 schematic but I believe the attached 65 schematic is very close. There is an ammeter shunt within the engine wire harness. I would check the shunt and attaching wires (black and black/white) to check for corrosion. There are new wiring harnesses available for your car.



Search Parts


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## O52 (Jan 27, 2019)

I cropped the original schematics for easier visualization.

The ammeter light is for illumination, not the charging light thats in the A body Tempest cars


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## Maczuga (Sep 16, 2020)

Hey guys,
I just switched the vr‘s again (put my factory one back) and the alternator is working again. So, it is not the fault of the wire harness but I think the new transistorized vr itself. As a matter of fact I bought it from AMES with the means of a 1:1 replacement.
However, I am thinking about the additional option of 1966 Pontiacs where You could add a factory called „fully transistorized ignition“. Might that indicate the change from electro-mechanical vr to fully electronic as it is with my new vr? If so, perhaps I would need to wire it alternatively. I have a scheme below:
As you see #3 prong is now moved to #4 and the field stays the same. What do You think, don‘t want to burn anything 😂


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## O52 (Jan 27, 2019)

The electronic ignition itself for the B body is very rare and hard to find. 
NOS electronic VRs are available from Ebay 

There are different designs of the electronic VR depending on model and terminals. See parts listing

























Delco Remy Voltage Regulator 1964 - 69 Chevrolet Pontiac 1116370 D637 Date 4m for sale online | eBay


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NOS GM 1967 Pontiac Voltage Regulator 1116370 D637 for sale online | eBay


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NOS Delco GM 1964-69 Pontiac 62 Amp Voltage Regulator 1116370 GTO | eBay


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## O52 (Jan 27, 2019)

PontiacJim said:


> O52 covered it way better than me. Learned the big cars are different than A-body charging systems.
> 
> Are all big cars wired this way, or just the earlier years?


I'm not positive Jim but I believe its from 63 to 68. The new internal regulated CSI alternators came out in 68 on the Grand Prix


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## Lemans guy (Oct 14, 2014)

I run a 12 SI (System Integrated) alternator on my 1966. It eliminates the external voltage regulator….That is an option unless you want the original look of an external voltage regulator.


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## Maczuga (Sep 16, 2020)

Thanks for the info,

however I still don't know why the new vr isn't working as it is. What I was suggesting is that maybe the new vr is ment to be wired up like the rare 66 transitsorized vr, that is in a different manner than my original factory one and for this reason at the moment inoperatable. Making it short: connecting blue wire of the F terminal to the alternators Field plug and the black one move from vr's prong #3 to #4 as to be seen on the transistorized scheme?

Speaking about the nature of the fuse on the output of the alternator, do You suggest that there was never an inline fuse and someone crimped it on for whatever reason?
Do You have anything in mind what could be the cause?

Something I can remember when I got this car was that the clock as well as the radio (AM) along with it's underdash speaker were burnt and some of the outer lights weren't working but unfortunately I was never told by the electrician what could have been the cause after he fixed all of that. The fuse holder came along with the car from the US, even if not this particular one but an american style fuse holder for glass fuses.


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## O52 (Jan 27, 2019)

If you look carefully at the schematics I provided you will note that the #3 and 4 terminals are jumpered together internally inside the regulator. It makes no difference if you connect the wire on 3 or 4.

I would forget about using the new 4 terminal VR. It is not the correct part , the car is not wired for it and as you found out, doesn't work for your application. 
The old regulator is charging the battery so it should be fine. Place a voltmeter where you can see it and the ammeter at the same time. Does the voltmeter fluctuate at the same time as the ammeter?

I believe the ammeter itself or the shunt may be bad. As I mentioned above unwrap the tape over the engine harness to uncover the shunt. Make sure the connections are tight and not overheated or corroded. 

In regards to the alternator fuse;

If your car is equipped with air conditioning it will have a second wire from the positive alternator post with a 30 amp fuse. This is the power source for the A/C system.
The fuse holder I'm referring to is the one circled. It is not from the factory. Is it connected to the alternator too?


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## Maczuga (Sep 16, 2020)

Yes,
I have a factory A/C from Frigidaire/Harrison. The only 30A rated fuse would now make sense to me 
It is cut into one of the two wires coming out from the loads from the alternator - seems to be a red/black stripe. Why the fuse holder was changed, I can not say. Is it possible to get somewhere the original style ones to maintain the classic look? By the way excuse my question but all I can buy here in Europe are glass fuses rated for 32V and not 12V. Is this a standard volt range?
To dispel my doubts about the ammeter, I have posted here a short clip of how it works on half warm engine with revving up. Maybe I just exaggerete and the ammeter's behaviour is normal.
I will look to measure the volts, as I understand it's okay if I measure between the battery poles? I know that the voltage spikes between some 14.4 and 14.6 but I will check that with the ammeter in sight.








66’ Pontiac ammeter


Any idea if this is the normal operational behaviour on a 1966 Pontiac ammeter?




www.youtube.com












Thanks,

Maczuga


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## O52 (Jan 27, 2019)

Ammeter looks like a loose connection. Has it always done this? 

32 volts is fine for replacement fuses.. As long as its higher than 12 volts.

That fuse holder will work OK unless you want factory original. I may have one in my spare wire box.


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## Maczuga (Sep 16, 2020)

As long I own this car, shipped it from Kansas in 2019. Previous owner did not drove much if at all, I am the third registered owner. Car has been sitting since the 90s. Never told me that sth. was done with the car besides what involved regular inspection.
Speaking about that fuse holder I can't even find what they should look like, I have a picture of mine former one when I was taking the whole engine bay but unfortunately the angle of view doesn't allow me to tell what it is as whole. Searching the internet does not help also.

Back to the ammeter - looking at the wiring diagram I should have a black and white/black wire going to the ammeter. Is there any way for a greenhorn like me to test it, I mean besides checking for loose connections?


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## O52 (Jan 27, 2019)

Its best to talk to Pete Serio of Precision Pontiac in Ohio. He is one of the best in the business rebuilding these gauges and can guide you better than I can. 



Precision Pontiac Contact Us


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## O52 (Jan 27, 2019)

The A/C fuseholder is white. Is that connected to the alternator on your car?


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## Maczuga (Sep 16, 2020)

Yes, that was the fuse before it was replaced by a mechanic I wont speak of. This picture is two years old and in place of that old one is the new I have posted on the previous pic. I don’t have any other pictures of old and retrieving the original fuse holder is not possible. That is why I am asking how it looked like and where to get it so I can refit to original look.


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## O52 (Jan 27, 2019)

I have a spare fuseholder from my box of wires. PM me (start conversation) for details.


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