No Charging from Alt 1972 Z

[stevef1972z]

I have a situation will the car will not charge. Started with a bouncing amp guage, thought bad alt or voltage regulator, replaced both with new. No charging. Car will start and run on just the battery, accessories work. Fusable link at starter has continuity. Took replacement Alt back to parts store got another one (5 day wait) put it on, no difference. Tried old voltage regulator with new alt, no difference. I have continuity to the W/R to the fusebox. So I have old alt and regulator and new alt and voltage regulator. AMP guage will show negative if you turn on accessories but will not show a positive charge with any combination of parts. I looked for links on this and saw that 72s may have two fusible links, and one is at the

alt. I have continuity through the wire off of the back of the alt. Am I missing something really simple? Suggestions please, we have a car show next weekend, I have not been able to drive all summer. I want to be out with the car this year.

[5thhorsemann]

Did you check the voltage at the battery? Does the amp gauge read correctly as accessories are turned on and off?

[stevef1972z]

Battery is new, voltage is 11.97 now having messed and started several times with no recharge. Voltage drop at the battery matches with the AMP guage. Battery does not show additional charge from any combination of alt or voltage regulator.

[5thhorsemann]

Did you try the old alt with a new reg? Is the new Alt internally regulated?

[stevef1972z]

Both of the new ALTs were externally regulated. I have tried the new voltage regulator with the old alt, no charge, no charge with old alt and old voltage regulator, no charge new alt and new voltage regulator, no charge new alt and old voltage regulator. I have a rough time believing the two new alts were both bad. Even my luck would not be that bad. The good news is that I can change an alt really fast now with all the practice!

[5thhorsemann]

Did you check the output of the alt at the alt directly. If there is nothing there your field connections might be an issue.

[stevef1972z]

Yes voltage from the alt is 14.5 at 1000-1200 rpm, yet nothing getting to the battery, it is draining and not getting a recharge.

[Walter Moore]

There is a fusable link between the alternator and the wiring harness. It sounds like either that link is blown, or not hooked up properly.

[stevef1972z]

Where should that fusible link be Walter? I have no idea where it is? I cannot find another link other than the one on the starter that is good. Any help would be appreciated, needs to be running, if its not I cant sell it and i am done with this car. I thought the Lucus wiring was bad in UK cars this thing takes the cake!

[Walter Moore]

The black wire that actually connects to the output terminal of the alternator is a fusible link. (According to the FSM) It connects to a White/Red wire (which is one of the largest gauge wires on the car by the way.)

You should have +12V on the B+ (output) terminal of the alternator with the engine off. If you don't you have a break in the wiring. I suspect the fusible link is open, or you have a broken wire in that area.

[stevef1972z]

No wonder I cound not find it, it is not there, the W/R wire connects directly to the alt. so I guess somewhere along the life of this car it was removed. I have continuity through that wire to the fuse box. Thank you Walt, the archives just say it is by the alt, no description, so I appreciate your time.

[stevef1972z]

Continuity from W/R to battery, when all connected I show the same voltage at the Alt connect as at the battery. Checked ground circuit, I have continuity through the line. Added additional ground to negative to chasis, added ground from alt to chasis. No Charge. Disconnected all connections, tested alt output. Idle 3.48 1100rpm 4.86 seems very low to me.

Question, this is alt 3, is something in the car eating them? What would destroy the alt instantly, I have never got a positive reading since the fluction on the amp started and I replaced battery, alt and voltage regulator.

I had to walk away from it today, I am very fustrated, everything is torn apart testing and cleaning connections.