Voltage Fluctuations

[Joe Stang]

I am going to print out the wiring diagrams now BUT, I have a heavily modified 71 H code.

I just had Midlife redo the under hood harness and they did a great job.

This has nothing to do with them . I have made some mistake in reconnecting the wiring harness and am getting a 11 volt to 16 volt fluctuation and can't figure it out. It is constant every few secconds.

I have the battery in the truck with a disconnect switch for a long time.

I just replaced the Voltage regulator and had it tested since then and it's ok. It also has a new alternator.

I can't find the smoking gun on this one yet.

I do have the ground from the alternator going to the block, and then a large Mallory stainless steel ground strap going to the frame. The diagrams on the website show the ground going to the regulator?

I have several books/many on the car and haven't seen anything obvious yet.

I backed the car out of the garage and had the Voltage regulator plug undone and it was running of the Battery only with no fluctuations. So I am thinking this points to the Alt?

I added a few gauges to the dash too so it's tough to track down what’s going on with all of the changes. Any suggestions or pointers will be welcome , heck even speculation would be appreciated !

Are there any Tee shirts for this website we can buy?

Thanks brother and sisters !


Wow. Smoking Regualtor post has some good info on it. I don't think the stator wire on mine is hooked to anything !

Ford external should hook up like this.

Voltage regulator teminal (I) goes to key switch Acc or Coil Risistor

Voltage regulator teminal (A) goes to Alternator Battery Connection

Voltage regulator teminal (S) goes to Alternator Stator Connection

Voltage regulator teminal (F) goes to Alternator Field Connection

 

[hyena429]

I am going to print out the wiring diagrams now BUT, I have a heavily modified 71 H code.

I just had Midlife redo the under hood harness and they did a great job.

This has nothing to do with them . I have made some mistake in reconnecting the wiring harness and am getting a 11 volt to 16 volt fluctuation and can't figure it out. It is constant every few secconds.

I have the battery in the truck with a disconnect switch for a long time.

I just replaced the Voltage regulator and had it tested since then and it's ok. It also has a new alternator.

I can't find the smoking gun on this one yet.

I do have the ground from the alternator going to the block, and then a large Mallory stainless steel ground strap going to the frame. The diagrams on the website show the ground going to the regulator?

I have several books/many on the car and haven't seen anything obvious yet.

I backed the car out of the garage and had the Voltage regulator plug undone and it was running of the Battery only with no fluctuations. So I am thinking this points to the Alt?

I added a few gauges to the dash too so it's tough to track down what’s going on with all of the changes. Any suggestions or pointers will be welcome , heck even speculation would be appreciated !

Are there any Tee shirts for this website we can buy?

Thanks brother and sisters !


Wow. Smoking Regualtor post has some good info on it. I don't think the stator wire on mine is hooked to anything !

Ford external should hook up like this.

Voltage regulator teminal (I) goes to key switch Acc or Coil Risistor

Voltage regulator teminal (A) goes to Alternator Battery Connection

Voltage regulator teminal (S) goes to Alternator Stator Connection

Voltage regulator teminal (F) goes to Alternator Field Connection

It could be your alternator...You should take it off and run it into a napa or some auto shop over your way...and have them check how many volts its pushing out and how constant.....only thing i ever seen do voltage surges like that...Was when i accidently hooked my battery backwords on my old truck for a sec..But i caught it quick before it fried all my wires....I would be going down the road and my radio would fade..then come back alive strong...But i think i melted some fuselinks is why...And toasted my alternator a bit im sure.....I hope its a easy fit...but i would take that alternator in first before you get too deep....Then trouble shoot from there.

 

[midlife]

The alternator is usually grounded to the battery and to the block. I wonder how good your ground is via the chassis to the battery in the trunk.

Your harness is for a non-tach dash, and that usually means all four of the VR connectors are used.

The description of your voltage fluctuations does indicate a bad voltage regulator/alternator system somehow. Since you can run on the battery without fluctuations, you can pretty much rule out the new gauges, unless one of them is tapping into an alternator line. I believe you have isolated/removed the VR by disconnecting the plug and starting the car: the battery will get unregulated voltage from the alternator and may be up to 18V. I would not run it this way for more than a minute or so, but that's enough time to see if you still have fluctuations. You actually have to disconnect the alternator battery connector at the alternator to disable the alternator sending voltage to the battery. Based upon your description, I'd have to point to the VR or a bad ground. The VR has to have a good grounding point as well; that's done via a separate ground wire to the chassis or another ground wire underneath one of the VR bolts. Make sure that there is no paint between the VR grounding point and the chassis.

 

[Joe Stang]

I thought for sure I was on top of this but I have looked @ the 1975 chilton book,the Vot reg smoking post(on this site) and diagram and the 71-73 diagram on this site and am more confused than before. I read Midlife's post again and I did just paint the inner-fenders so there is a great chance that the Volt reg ground IS the issue. I am going to go re-install the reg and use a star (serated) washer on it.

Back when Midlife did my harness He sugested a new Alt harness too. The best/most accurate I have seen is on a Cougar parts site!

Any sugestions on who to get the right harness from? I have a non-gauge car.

The Vot Reg post shows the stator wire hooked up for sure to the regulator(white w/ black wire). Just for fun I checked my 1970 Fastback and it is set up like my 71 and NO STATOR wire hooked up to anything.

So one more thing. There is 3 terminals and a space , and then the 4th terminal @ the bottom of the plug. Why does NONE of the digrams show the space so non-stock guys like have a some kind of reference point! There I said it. Thanks guys/gals for letting me vent......

 

[72HCODE]

just FYI i had 3 bad voltage regulators in a row, these were the reproduction regulators, i would put one in and the the lights would be flickering, this happened over and over until i swapped in what i thought was a junk regulator and the flicking issue went away.

I returned my regulator, got another, same problem, returned it got another same problem, returned it, then the heavy duty reproduction unit came out i went for it and it worked.

Go figure...

 

[Joe Stang]

just FYI i had 3 bad voltage regulators in a row, these were the reproduction regulators, i would put one in and the the lights would be flickering, this happened over and over until i swapped in what i thought was a junk regulator and the flicking issue went away.

I returned my regulator, got another, same problem, returned it got another same problem, returned it, then the heavy duty reproduction unit came out i went for it and it worked.

Go figure...

Now this knock-off-Autolite-$20-to-good-to-be-true-EBay-reglator does not look to be so good. I did have it tested @ Autozone and I watched it pass the tests. I do need to state the Regulator is the one labeled I(ignition) space A(alt),S(stator)F(field). It's stamped on the Cover and molded into the plug too so please ignore my previous anger based ramblings. It's stamped/painted D0AF-10316-A. Sure nicer looking than silver genric old unit.......

 

[midlife]

NPD has several alternator harnesses (www.npdlink.com) for the 73.