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Questions: Indicator Lights and 3G Alt wiring!

mangustamangustaMember
OK, here we go again!

Prev owner installed 95A 3G alt in the car, and when I first drove it, alt belt was slipping somewhat fiercely eventually shucking it off...leading to my other adventures with heater/AC system....wiring clean up.... I attributed this to a loose belt....but now I wonder about that...

FINALLY took the car out for it's first run after all this other hoohah....and I could still hear the alternator squealing occasionally.....this shouldn't be!


If I can believe my notes, the Alternator (95A 3G style) is wired correctly.

Main output hot wire "B+" reuses original large wire which passes back thru AMP gauge in dash and then on to the battery. (Some doc's say bypass the amp gauge wiring and go directly to battery.... as another way to do this.)

3-wire connector wiring:
"A" Yellow wire connects to main battery connection at the starter solenoid I believe IIRC! This is voltage "remote sense" for the regulator. (some doc's want you to put this at the battery also....not just jumpered over to the alternator output as some would have you do cuz it's easier.....in long battery cable runs this short method may not work as well..)

"S" White/Black wire connects to the "S" plug on the back of the alternator. This is some sort of local sense deal.

"I" Lite Green/Red wire connects to "blue" wire from old regulator connection, which goes up to the dash lamp for GEN indicator in TACH. "Switched voltage" from ignition switch passes thru this lite to the "I" terminal of the regulator.

My problems:
1) Amp gauge shows LOTS of charge, at speed, upwards of the 75A mark, but it "waggles" a good amount also. As I slow down, the amp indication drops also, ie at idle, but was still showing a good amount of charge. Battery wasn't dead, but perhaps not fully charged, and I didn't drive it but about 4 miles or so. (Charged it last nite on external charging.) Have not started/driven car today to check behavior.

* I would expect to see a 20-30A charge indicated with a low battery, but not 75! *

2) I have no dash indicators coming on when switch is moved to "on" position. What lamps are supposed to be lit when the car is not running????? (I need to look at SOBill's diagrams to see how charge lite is wired...series or parallel....)


I am thinking that the "I" terminal of the regulator is not seeing a voltage (if the bulb is blown!??) back to the regulator, but this is not the "S"ense connection..... Documentation that I found says you want it to "switched" voltage source (when key is on).


I also found where a 560 ohm resistor is recommended "around" the dash lite, in the event that it burns out....the "I" terminal still gets voltage via this feed. (for whatever purpose...) But this would seem to be needed only in the event that the bulb is in series with the current flow ie one side of bulb is not grounded but rather this switched voltage passes directly thru the bulb.

I need to bail....and may not be able to get back to this for a day or so......but I need to put this out to keep the brain happy....otherwise will have "alternator on the brain" all day!!!....and nite!!!

I will go back and check for switched +12V at the "blue wire....and resolve that. See if it resolves my issue! May need to get some 560 ohm resistors as well!

Other indicators thing will be handled as I get info....

Oh, one last thing! I recall a "short here to test" thing molded into the back of the regulator..... Short to ground and look for what??? Anyone know how this functions in testing the regulator?

Thanks!!!
Steve
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M mkehMember
This may seem fairly obvious and likely already checked, but have you looked for a mechanical issue with the alternator? bad bearing or pulley rubbing?

You probably recall the issue I recently went through with the alternator bearing on my goose...

perhaps disconnect the wiring and fire it up, see if the noise is still there...

MH
R rene4406Member
75A is a lot!

Measuring voltage is also a good way to check if the regulator is working properly. If the regulator malfunctions because of a bad wiring or because it is out of order, the alternator delivers too much tension and therefore too much current, it increases the resistance to the rotation and makes slip the belt.
It can damage the battery, alternator, ignition and all electrical devices.
N noreasterMember
Noticing a similar belt squeal problem with a 3G installation.
It has the internal regulator and is wired to use the dash indicator lamp. The yellow sensing wire goes to the battery cable stud on the starter relay and I added a 6 ga cable from the alternator output stud to the same stud on the relay as the yellow sensing wire.
Belt just howls until battery drawdown from starting is recharged, then it's ok. Like Mike suggested, I removed the wiring from the alternator so it was just acting as an idler pulley and no squeal at all.
Amp gauge has been replaced with a voltmeter so I cannot tell what the amp load is, but voltmeter shows about 14v at idle.
The 3G came with a serpentine pulley installed. I had initially tried a reduced diameter vee pulley, about a 1/2" smaller in diameter than stock. I figured that would pick up alternator RPM lost to the smaller Pantera crank pulley. The squeal was instant and wouldn't stop. Took the alternator to get it checked out. It tested fine on my guys machine with a 180 degree belt wrap, but he suspected the squeal problem was the combination of the reduced pulley diameter and the maybe 100 degree belt wrap on the car. He recommended trying a larger pulley.
I removed the stock sized pulley from the original alternator. It was a little rusty so I sandblasted it, making sure I got the glaze off the vee area the belt rides in. Before I painted it I masked off the v to keep the paint off that area so as to maintain as much tooth for the belt as possible.
Putting that back into the car got me where I am now, a few seconds of squeal then good. But the duration of the squeal is proportional to the cranking battery drawdown. After an extended cranking period the squeal is extended.
I'm going to find an even larger pulley and try that next.
mangustamangustaMember
Very quick update! Gotta go get sexy for a birthday thing.....

Charged bat: at rest 12.75V
At start, higher idle: 14.9V

Low idle: 15.0-14.97V Meter waving at 0-35A (mid range)

About 1000 rpm, needle smooths out and holds stead at about 5A or so just off of zero.


Indicators: Two cars here.....one has red light when parking brake is pulled one has yellow...probably one is mixed up! NOt sure what the other one is....pad wear indicator?

Neither cars have any bulbs illuminated with switch at "on". Was expecting to see GEN lamp lit....nada!

OK, gotta go get it on!

NorEaster: Will get back to you on pulleys and 3G! Three...small, slightly larger, and huge! Look up optional Boss 302 pulley!

Cheers!
mangustamangustaMember
Nor'easter,

Pre-First: I think my alternator is working properly. GEN lamp is not perhaps.... But basic operations is sound, just the needle flapping in the breeze is unsettling!

FIRST: let me apologize for not documenting any of the alternator pulley work I did when I went thru this early this or late last year..... I didn't even take pic's for myself! Apparently I was to deep into hoses and other crap!!!


One VERY important thing that I ran into with these pulleys "on the Ford G3 alternator that I have"(!!!) is that when used as found, there are only enough threads sticking out of the pulley to get a nut on about 2-3 threads....Not quite the engagement you want for something on the front of your engine!

I had to take some XXX amount off the rear flange IIRC, in order to get proper pulley alignment and gain good thread contact and allow a lock washer...for my tastes!

My alt came with a modified "C9AF" pulley, but a quick look in the parts book indicates that the "C9" pulleys are the same size, at about 2-3/4" diam as the C5AF versions. I think I am now running a modified C5AF-10A352-L that I pulled off of a rebuilt alternator I had laying about....as the one that came with the car, had slightly damaged sheave (groove) from belt slipping perhaps.

If you put a stock pulley on, it will be too far forward for proper alignment. I had material removed from the rear mounting area.

For some reason, it seemed like the original C5 pulley was mounted backwards and perhaps shortened...... fuzzy memory.

I would expect the Boss pulley to need some material removed also.

Here is a rundown on pulleys from the Ford Master parts book for you: (part numbers "as marked" to the best of my knowledge!)

C5AF-10344-K,-J2 2-3/4" Dual groove (which we can't run due to only having two groove pulleys...where to put the AC belt?

C5AF-10344-L, C5TF-10344-G 2-3/4" Single groove
C9AF-10A352-B, -A2 2-3/4" Single groove

C5AF-10A352-H "HiPo 289" 3.9" Single Groove

D1ZF-10A352-A 1970 Boss 3" single groove

D2OF or D2AF-10A352- 3.15"

D1AF-10A352-A or AA 3.15" same as D2 version.

According to the parts book, these last two pulleys were used on LOTS of cars, Mustang, Cougar, Fairlane etc in 71 and 72 on 302, 351, and 429/460's! Perhaps even on the Pantera if the alternators came on the engines to DeTomaso!

But! What is bizarre, is that I haven't "noticed," nor can I find any of these 3" pulleys on ebay or via Google search........seem to be only C5AF and C9AF versions......and the others have evaporated!!!

So to boil that all down, you have 2-3/4" pulleys most common, 3" hard to find, and 4" which is available in repop form.....!

Pic of my engine with C5AF-L pulley.

......I wonder why people just don't upgrade to a good Motorcraft 65-75 Amp alternator with a solid state regulator and be done with it all!?? Do we need 95A? Just thinkin....

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N noreasterMember
My Auto-Electric guy didn't have one of the +/- 3" pulleys in his bone pile so I bought a 3.9" C5AF-H version from eBay. $41 to my door.
If it's here by the weekend I will try it out. Still need to get a bigger belt too.
Regarding the thread projection thing, I have full engagement of the thin nut supplied with the 3G using the stock 2 3/4" pulley. Hoping for the same with the new pulley.
mangustamangustaMember
N'E,

Lemmeno how that fits for fore/aft spacing! That was the most difficult to deal with in that I had to have the pulley hub cut to align properly, something I don't like to do unless last resort.

I also went around with the belt thing.....I opted to go for a 11mm (wide) belt instead of a 10mm belt IIRC.

I ended up with a Continental Elite belt #15411 (11AV1030.....1030mm long) The 10mm belt is a #13411 (10AV1040) so in addition to being more narrow the latter belt is also 10mm longer.

This puts the alt mid adjustment...not sure if the larger diameter pulley would require a longer belt or not..... Mr Murphy would dictate "yes"!!!

Cheers!
N noreasterMember
Pulley came yesterday. Alignment seems fine, no change from before.
I used a piece of rope to get a rough idea of required belt length and it seems I'll need a belt at about 42" (1066mm). Hope I have time tonight to stop at the parts store.
The belt does sit down in the new pulley a bit, yielding an effective diameter of 3 9/16". If I did the math right, at a 750rpm idle, the alternator should be spinning at about 1150 rpm.
P punkdogMember
First things first check the battery with a capacity/battery tester and make sure you have good connections on the pos and neg cables.
Battery in the front with engine in the back is a long cable run so the battery has to be strong with good cables. A must !
A prolonged 75amp charge rate will probably damage the battery and is a indication of a bad battery.
A 75 amp charge rate means that the alternator is working it's butt off creating a lot of heat and back EMF that could be why the belt is slipping.
Bypassing the amp meter will only eliminate your ability to monitor the system but do make sure the connection on the back are good. Disconnect the battery first !!!
The switched wire feeds the alternator field through the indicator lamp to excite (start) the alternator. If the lamp burned out you couldn't excite the alternator field/ start the alternator. Thus the wire with the resistor. It's a backup in case the indicator lamp fails.
The light should go out when the alternator comes on line.
Do Not short the field wire to ground to test the system. You'll have a runaway alternator and probably damage you electrical system.
The system operating voltage should be approx 13.8 volts warmed up. Much over 14 and you are nearing the danger zone.
Remember that you a dealing with 40 year old wiring so be gentle and look at it closely for damage.
Make sure that the v-reg is correct for the alternator.
My guess is you have a weak battery and or bad connection.
This came from my old brain, not a wiring diagram but most systems a built alike. Even so look at the diagram.
If all else fails return the system to it's original configuration and it will work fine.
Be aware that cheap alternators are just that. Cheap Chinese junk.
Be careful... Large cables means a lot of current.
Good luck.
mangustamangustaMember
P-dag,

All good stuff!
Not seeing a steady 75 but a "waggling" needle that is all over.....on the charge side....

I did charge the battery and it did settle the needle down.

Now, let me elaborate a tad.....I was seeing this on TWO cars!

Both batteries are good. #1 is months old, @#2 is a couple of years old but holding charge well. No large drains on system while "off" (5-10ma observed max)

Car#1 (1974) has modern Ford 95A onboard regulator alternator.(this was the car that started this post....)

Car #2 (1973) to my knowledge has stock alt and stock style regulator (although I don't know if the reg is conventional stock or updated solid state reg) The car came along after I had started this post.....and am using it as sort of a standard....but then I find out that this thing is waggling the gauge needle also!

A LOT going on in my life presently, so a little..OK a LOT distracted...doesn't help! I charged battery #2 and after starting it still saw "similar" waggling.....but since I was putting it on a trailer, I sort of lost track....and can't say if it settled at all........once it warmed up and got off the high idle....

The circuit diagram I was looking at the other day showed a 15 ohm resistor "should" be in the circuit across the charge lamp already for exciting the alternator.(corrected ohm value 6-8-18) But neither car exhibits a gen lamp ON condition running or not..... so I guess I need to check some bulbs!!!! That would be easy....I hope chunky fingers will fit up there now that it's all put back together.......doh!

I'm just trying to figure out what the "norm" is for these cars (new to me!) with some of the mod's (or not!) that guys have done in this direction! Hopefully this will help some other new owners as well!!!

Thanks!
Steve
Last edited by mangusta
P punkdogMember
Me too.
My guess is that the light goes out when the alt is working. Like most cars.
Check the sense wire to the v-reg.If that is bad the reg will tell the alt to get going.
The best contact cleaner I've found in forty years is WD40 and scotch brite.
Looking at my bat pos cable the other day the terminal came off with a slight tug.
Where did you find a wiring diagram ?
Just wondering, Why a 90amp alt ? That's a lot of current.
mangustamangustaMember
P-Dag,

I was helping another member put his car back together and he had the diagram. Not sure where he got it, but one LARGE sheet....was tough keep the eyeballs focused tracing wires.....!

I just checked my SOBill diagram and it was a 15 ohm resistor shown across the amp gauge. You can find these diagrams at Mike Dailey's "Pantera Place". He boiled down a LOT of stuff into smaller chunks by operation...check 'em out!

Why a 90? because the previous owner thought it was a good idea.....I'd have been happy with a 65-70A version....I do like the onboard regulator thing....that Ford uses.....along with the "brush module" for easy replacement....

Cheers!
N noreasterMember
Tried out the new pulley last night. No squeal, 14.7(+/-) volts on the guage at a reasonable idle speed (we're using one of the matching Veglia faced voltmeters).
We used the 10MM belt for two reasons. First, it fits perfectly in the crank and water pump vees (we're using one of Scott Bells reduced diameter aluminum pulleys).
The new alternator pulley has a very deep vee and could properly handle an 11MM belt but the narrower belt sits deeper in the vee and reduces the effective diameter of the alternator pulley a bit, picking up the alternator rpm.
bosswrenchbosswrenchMember
Steve, the 'wagging needle' on your amp gauge has been a problem since the Pantera rolled out of Modena. Cause is supposedly because 100.0% of the alt's charge goes thru the gauge. To eliminate excess movement, fashion a shunt directly across the gauge posts and hook up as before. What will happen is, a proportion of the charge amperage will bypass the gauge thru the shunt- the amount depending on the physical size of the shunt. I have one made of .060 brass shim stock on our car, and I've made a couple from 10 ga stranded wire. Insulate the shunt with shrink-tubing before bolting it in, and be SURE the nuts are tight! As I said, ALL the charge from the alt is going thru that wiring and some in a hurry or with no mechanical skills have had console fires here.

After adding the shunt (any size), the gauge needle will read low but will be stable. Accuracy? Questionable even in stock form; how do you read a needle that's thrashing around? Most owners are satisfied that the needle moves toward + and doesn't shake, not exactly how much it moves. Think of the amp gauge as a moveable idiot light.
mangustamangustaMember
....moveable idiot light....that's pretty good Jack!!!!

What about the (supposed) 15 ohm resistor that is supposed to be there....according to some diagrams...... I think that the alternator folks recommend that to be a higher value, of which I can't recall at the moment....may be elsewhere in this post....that are supposed to be for the GEN light to pass current thru.....(?) when that works...... (Still need to pull bulbs and see if they are even any good.

I'm liking the voltage gauge idea instead of the current "ampere" gauge....

Can't get any word from anyone yet if the GEN light should light at the ON key position....or exactly when it should work!

I guess as long as the gauge needle wagging wildly isn't going to hurt anything.....I can condition myself to ignore it....hopefully......!

Cheers!
Steve

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