Low voltage 3G... Possible improper wiring...

[gmatt]

I think I've read all the posts, but I can't recall if it's been asked whether you're running underdrive pullies? Just spitballin'

[congerz83]

I think I've read all the posts, but I can't recall if it's been asked whether you're running underdrive pullies? Just spitballin'

I'm not sure... I don't think so

[congerz83]

Have you disconnected the battery, negative lead first, while the car is running, and measured the output voltage on the alternator +ve stud to see what it is putting out?

Will I damage anything buy disconnecting the battery while the car is running?

[congerz83]

I found this wire disconnected under the solenoid... I got overzealous with the cleaning so it looks solid orange. I actually think it's black with a orange tracer.


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[congerz83]

This wire is actually black w/sky blue tracer.


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[grabbergreen84]

Will I damage anything buy disconnecting the battery while the car is running?

I wouldn't want to try that on a '79-'85, and I know to not try it on an '86-and-up.

Just because that 'test' doesn't blow up your '68, doesn't mean that it's a good testing procedure.

[danco86]

Agreed. I guess I haven't tried that in 20 years or so.

I think I remember seeing a wire like that on my car during my build, and it wasn't connected to anything either.
Anyways, it does seem that your wiring to the alternator is correct, and functioning properly. I run underdrive pullies on my car, and I still put out >14V at idle.
Have you had the alternators checked?

[congerz83]

So six years later, brand new 408 just installed. Holley Sniper. Wouldn’t you know, the same damn problem. I’m going to wind up re-wiring the whole charging circuit.

[Fast_4_Eye]

So six years later, brand new 408 just installed. Holley Sniper. Wouldn’t you know, the same damn problem. I’m going to wind up re-wiring the whole charging circuit.

Have you turned it off and back on again?

[congerz83]

Have you turned it off and back on again?

Not sure what you mean…

[massacre]

So six years later, brand new 408 just installed. Holley Sniper. Wouldn’t you know, the same damn problem. I’m going to wind up re-wiring the whole charging circuit.

With a new Holley sniper, rewiring the entire charging system might not be a bad idea. At least then you'll know it's done right. Just imho

[radartek]

Also, set the dial on the multimeter to VDC 20

Concur. Not sure why you have the meter selected to BAT 9v. Set it to VDC 20. What year is your Mustang by the way? The early foxes 1G alternator (1979-1981) had an external voltage regulator. When you install a 3g you must switch the regulator module out to match with the new 3g. The 3g's are internally regulated and so there's adaptation that need to be done. I bought my 3G alternator from LMR, but I ordered the replacement PA-Perfomance regulator "housing" that adapts to the 3G from PA Performance (www.pa-performance.com).

[KevinK]

1G alternators we're still used in 84.

[congerz83]

SOLVED!

New "self exciting" alternator still wasn't charging. Turns out my pulleys weren't lined up. After 6 years I can say I HAVE VOLTAGE!

[85GTGuy]

1G alternators we're still used in 84.

Also still used in 1985.