3G alt Problem

Skoobie · Mar 12, 2007

Ok I installed a 3G a year and a half ago. I have read almost every write up on the subject that could. Followed every step to the letter. Heres my problem. When I start the car it charges great...about 2-3 bars above the "charging" hash. As I drive the car the needle slowly drops until eventually it is hanging 1 hash above the red zone at idle. I have a set of underdrive pullies (I kept the stock pully on the alt though), a small stereo (300W amp), and NO AC. Is it heat soak? After it gets warmed up my headlight start pulsing and at times it even effects my idle (get choppy if I sit too long at a light). I have TWO 4g ground wires. Im getting 14.3-14.4 amps at the battery (at least when I first start it up, havent checked it after a longer drive), and the main power lead it also a 4g wire. Oh and it seems to charge ok when Im driving (1-2 bars above the charge hash after it warms up). The problem is when it idles down (650-750rpm). Hell my old 2g alt charged that good after it warmed up....what else could be wrong? Where should I start?

04sleeper · Mar 12, 2007

Sounds to me like a bad voltage regulator or possible loose/bad connection.

Have you checked all your connections and grounds?

Darkwriter77 · Mar 12, 2007

First off, buy a REAL volt gauge. The stock one is a piece of crap. Mine reads all over the place at random times. If I believed everything the OEM gauge told me, I'd be replacing pieces of the charging system every other day, trying to figure out what's wrong with it. The Autometer volt gauge, however, always reads 14 volts or higher.

If you don't want to hard-wire a voltmeter into place, you can always look into getting one of those handy-dandy voltmeters that plug right into your cigarette lighter outlet. They're not 100% accurate, being that the contacts on most cigarette lighters are a little corroded and might give some odd readings at times, but they're better than the stock gauge and they give you an actual NUMBER instead of a totally vague guess.

Why it is that Ford thinks nobody wants/needs to know the actual numerical temperature, volts, oil pressure PSI, etc. on a car is beyond me. Just watch, it won't be long before they dumb-down the speedometer markings on new models to read something like, "Stopped, School Zone, City Street, Highway, and TOO FAST!"

I get a little bit of a voltage drop, myself, as things heat up. It's not as visible in the cooler months, but now that temps are getting up in the 90's down here in the daytime, I read 14.5 volts from startup and then just a hair above 14 (maybe 14.1) volts when I'm at full operating temp.

Skoobie · Mar 12, 2007

Well I have been taking reading with a multi-meter at the battery and getting 14.3-14.4 at startup. As for the crappy stock gauge I was just using that for reference...the real issue is the dimming/pulsing head lights and the choppy idle when it gets to low. My point is I shouldnt be seeing any of these symptoms with a 130A alternator

HISSIN50 · Mar 13, 2007

I would also have it load tested. I like to let them do it several times to heat the alternator up. With most machines you can also request an amperage output value. Make sure the value doesnt suck (which can indicate a bad diode, etc).

Otherwise, for alt testing, there isnt much to do. On the regulator, A = battery voltage. S = Stator circuit. I = 12 volts with the key on. Thi is just the excite circuit.

I'd check the charge cable voltage-drop real quick - it takes 10 seconds and can possibly give an idea about a resistance issue (I'm sure it's good but it's nice to rule it out). Look for less than 100mA drop on a newer cable (my last homemade one dropped ~5 mA).

Random thoughts. Good luck.

Darkwriter77 · Mar 13, 2007

Got to thinking ... when you say you're using the "stock pulley" on the alternator, are you using the one that came on the 3g, itself, or did you take off the one from your 2g and put it on there?

I had a tiny bit of headlight dimming going on when I first installed my 3g because I kept on the HUGE alternator pulley that came with it, because it was turning much slower at idle than it needed. I swapped the pulley a week later with a smaller one that was closer to the 2g size from a core trade-in at work (ah, the perks of when I used to work for Autozone) and I've since had no problems whatsoever with dimming or low readings.

Skoobie · Mar 13, 2007

Darkwriter77 said:
Got to thinking ... when you say you're using the "stock pulley" on the alternator, are you using the one that came on the 3g, itself, or did you take off the one from your 2g and put it on there?

I had a tiny bit of headlight dimming going on when I first installed my 3g because I kept on the HUGE alternator pulley that came with it, because it was turning much slower at idle than it needed. I swapped the pulley a week later with a smaller one that was closer to the 2g size from a core trade-in at work (ah, the perks of when I used to work for Autozone) and I've since had no problems whatsoever with dimming or low readings.

I put the stock 3G pully back on. I dont have the 2G alt anymore And my underdrive pully wont fit on the 3G (not that I would want it on anyway). Hmmmm...wonder where I could pick one up?

Skoobie · Mar 13, 2007

HISSIN50 said:
I would also have it load tested. I like to let them do it several times to heat the alternator up. With most machines you can also request an amperage output value. Make sure the value doesnt suck (which can indicate a bad diode, etc).

Otherwise, for alt testing, there isnt much to do. On the regulator, A = battery voltage. S = Stator circuit. I = 12 volts with the key on. Thi is just the excite circuit.

I'd check the charge cable voltage-drop real quick - it takes 10 seconds and can possibly give an idea about a resistance issue (I'm sure it's good but it's nice to rule it out). Look for less than 100mA drop on a newer cable (my last homemade one dropped ~5 mA).

Random thoughts. Good luck.

So how does the voltage drop work? Do I turn have a buddy start the car while I check it at the battery terminal? And as for the regulator, shouldnt it either work or not work? It seems odd to me that it works fine and higher RPM and only has issues below 1000rpm...if it was a bad regulator it would seem that it wouldnt charge at any RPM? Hrmmmmm

:EDIT: Also does someone have a part# for a 94-95 3G Voltage regulator

88LX · Mar 13, 2007

i had a similar problem with my PA 130 alt. upon start up my lights would have a strobe effect and then as it warmed up they evened out. i called PA and they said that it is most likely the regulator and they should cover it. he tried to talk me into buying some wire kit, and then he said if that didnt work he would send me a new regulator. i plan on having him send me the new reg. since its now warm out.

jrichker · Mar 13, 2007

Here's some visual help for HISSIN50's suggestion to check the volage drop across the wiring.

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection: more than .5 volts across a connection indicates a problem.
See http://www.fluke.com/application_notes/automotive/circuit.asp?AGID=1&SID=103 for help for help troubleshooting voltage drops across grounds.

Skoobie · Mar 13, 2007

Thanks JR. I'll check it tonight. I called Schucks Auto Supply...they want $70 for a regulator....

HISSIN50 · Mar 13, 2007

If you do need a regulator, FFI sells a decent lookin (to me) reg for about 30 bucks IIRC.

Skoobie · Mar 13, 2007

HISSIN50 said:
If you do need a regulator, FFI sells a decent lookin (to me) reg for about 30 bucks IIRC.

Thanks Hissin, can you post a link or the phone# for me?

HISSIN50 · Mar 13, 2007

Skoobie said:
Thanks Hissin, can you post a link or the phone# for me?

That I can do.

Here's the regulator (near the bottom of the page).

And here's the installation tech note.

Please note that I have NOT tried this regulator, but if I needed one, I think it's the one I'd try.

Good luck.

Skoobie · Mar 13, 2007

Thanks again Hissin! Last question*. What size is the STOCK 3G alt pully?

*Author reserves the right to retract this statement at any time should his limited mechanical skills fail him...or he drinks too much.

HISSIN50 · Mar 13, 2007

It will take someone to confirm this but I believe the stock 3G pulley is 60MM. FFI has overdrive pulleys too (if that's what you were lookin at ). They're another item I'd try (good prices as I recall).

Good luck.

Skoobie · Mar 15, 2007

Well I tried the resistance test and either I muffed it up or everythings ok...I tested the alt stud-wire, wire-fuse, fuse-wire, wire-negative battery, positive batt-wire, wire-silinoid, across silinoid terminals, silinoid-ground, and all i got were 0.00 or -0.01....sooooooo that means its ok I think. Also I rechecked the voltage at all those places and im getting over 14.3 volts at idle. Although it does jump around with the idle, anywhere from 13.8-14.6. But most of the time it stays above 14. Still my gauge reads 1 bar above red after the car has been driven for any amount of time and my lights pulse and dim It dosnt make sense! Grrrrrrr!! Oh yeah I already posted this in my other thread but I pulled codes too, here they are;

KOEO: 34, 34, 41, 66, 91 KOER: 41, 91, 34

In that order.

Thanks for the help guys!

HISSIN50 · Mar 15, 2007

A couple of late night thoughts:

If you get a resistance reading of 0.00, at least with my meters, that would be cause for concern. The reading should be really really low (i.e. 0.1 - 2 ohms) but not actually 0.00. This would suggest no continuity, which is an open circuit (in this case, my meter reads I).

Does the battery/alternator keep showing good voltage even when your interior gauge plummets near the red zone? If you can sit there and watch one particular location's readings randomly jump around, in my experience that's been a bad connection. Not to say it's your issue, because it certainly could be regulator related, but connection checking is cheap............

Anyhow, if the battery and/or alt read significantly higher than your OEM gauge (as tested with your DM-meter inside the car), this could be a voltage drop issue with resistive interior wiring. This is not unlikely with our older cars.

Good luck.

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