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Voltage Regulator

7K views 68 replies 3 participants last post by  145566 
#1 ·
Finally took my car to an auto parts store to test the electrical system.

Battery - ok
Alternator - Ok
Voltage regulator - ok...UNTIL I turned on the lights, AC, and radio, then it registered as FAIL.

I got it tested at both O’Reilly’s and Auto zone; same results.

My question is - what’s the logical next step?

ALSO - I think my digital volt gauge is out of cal. Does that matter? Why would it be like that? (it will read about .8 volts lower than what the store readers and my Schumacher charger/reader says).

(this could very well be why I have a hard time starting the more I drive the cat throughout the day, no?).




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#2 ·
Is yours a “police package” Mustang” that has the voltage regulator separate from the alternator? Or is regular where the regulator is part of the alternator? Time for a new alternator if it’s the latter I think.
*Edit*
First off, what year is this thing?
 
#4 ·
It’s a ‘65 with the M-6007-x302 crate motor. Haha, so no, not the police package.
I can’t tell the specs of the current alternator - it’s chrome to match the dress up of the rest of the accessories...which in my mind is “all for show, not for go.” Def not external regulator.


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#5 ·
That’s what I was thinking, just wasn’t sure if there were a bunch of troubleshooting steps I needed to take to verify and then remedy.

130 amp alt - any recommendations or vendors?

I’ve got a/c, fog lights, 900w amp, retro auto sound head unit, plug my iPhone into the USB port for the stereo, electric windows, EFI.


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#39 ·
Now, I have run into a horrible situation. When go to start the car, all of a sudden it is making a disgusting grinding like teeth are shearing. I was attempting to fix some grounds and was cleaning off some corrosion. Can anyone tell me what these parts are?




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#41 ·
Ok, so here’s where things go crazy:

the wire that’s grounded - I took out the bolt, scraped off some corrosion and sprayed some WD-40 on and around the hole.

The ignition coil - I took off the connector boot and scraped off some corrosion

Then I attached a 16 gauge grounding wire from the alternator ground screw to the engine bay wall.

When I started it up, it made an excruciating crank noise like the starter was grinding. Then the radio display started pulsing different colors. Then when I stoped, the turn signal noise was clicking but the turn signals weren’t flashing. I pulled the turn signal fuse and it stopped.

WHAT IN THE WORLD HAPPENED??


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#44 ·
Bad grounds can make a car do funny things, but it’s not all that hard to get a good ground. I mean if it’s tight on both ends and it’s metal on metal it should be ok. It doesn’t have to be bare metal. The OEM body grounds are grounded to painted surfaces. Did you do all three things and then it wouldn’t start? The alternator ground, that ground on the manifold, and the ignition coil? Or did you do the coil and the WD and it acted weird so then you decided to change the alternator ground to the firewall?
If one was to disconnect the wire that runs from the distributor to the coil (the boot) and tried to start the engine it would turnover real fast but not start. I don’t believe it would sound like a “bad starter noise” like you described. That being said, I think a bad coil would act in the same manner as a disconnected one.
I’d try to find a schematic for your Painless Wire harness to try and find out what the wire goes to that you sprayed WD in the hole. I don’t think the trouble is on the end you were messing with but is it possible that X wire touched Y wire and shorted something out? Or possibly that wire broke or broke another wire?? I’m just taking guesses. I don’t have a ground like that on mine so I have no clue what it goes to. If I do have it I didn’t see it.
 
#48 ·
And to be specific about the sound, it sounds like Turing the key to start once the engine already running...but it does that right off the bat on start.

(I’m trying to figure out if anything I did would cause that. Or was it just a coincidence that my starter went bad at that very same time of day)


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#52 ·
Turns out...I did need a new starter. But now the car drives kind of funny. Surges a little (more than it used to) and when I stomp on it at cruising speed, it hesitates and makes a weird grumbling noise...not a sexy engine rev noise.


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#55 ·
Is the alternator not charging the battery?
If it is, I’d leave it alone. You don’t want another ahh craaaap..
If it’s “driving funny” it’s not the alternator.
If the battery wasn’t getting charged it wouldn’t run very long before it’s drained.
 
#56 ·
I keep a tender on the battery. The first start is pretty good. I’m f I’m working on my car and start it about 4-5 times, the last start is almost a no-go.
When I drive around town, it gets harder and harder to start throughout the day.
The volt gauge is about 12.2 on my first street. Goes up to about 13.6 while I’m driving, drops to 12.0 with ac on and I turn on my blinker. With headlights on it dips below 12.0. And it drops appreciably when I coast.


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