Voltage Regulator Problems

First the stats

66 Mustang 200 cid
68 block
63 head

I am having problems with my voltage regulator. The entire starting and charging system including the wiring harness is new. All grounds have been triple checked. If I install an "Autolite" Voltage Regulator from one of the parts houses I get to much charge with the Amameter swinging completly to the C when car is running. When I install a Voltage regulator from Autozone I get to little charge and the battery dies. I have changed the Regulator a few times now thinking that I had a couple of bad units. But apparently not. Any help would be appreciated. Thanks Ed

are these electro-mechanical (relay type) units (tall can), or solid state units (short can). The relay types are adjustable, and need to be set to your alternator.

fb71":2ceskh6l said:

are these electro-mechanical (relay type) units (tall can), or solid state units (short can). The relay types are adjustable, and need to be set to your alternator.

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The Autolite unit is a "Tall Can" The Autozone unit is a "Short can" But both are sealed. One of the voltage regulators I tried did alow you to open it up and gap the relays but the smallest amount of change in the gap produced the wildest results. Way to much charge to no charge

then I would have the alt checked, even if new/rebuilt (most chain store units are crap). It sounds like the rotor brushes are crap.

Did that year vehicle come with an alternator or a generator? Possibly the regulators are incompatible with the new alternator?
Joe

I think in 65 the ford cars came with alternators. Not sure about trucks. My 66 shop manual for the smaller cars only shows alternators.

Do you have some sort of a problem other than the amp gauge? I have an international tractor that my boss has the shop try and fix the amp meter every time its in the shop because the needle seems to go wacky but I have never had any problems with the thing. It is a diesel and I dont use the headlights very often so its possible that I have just been lucky the last 3 years. Have you hooked up some sort of volt meter to see what the voltage is doing? Maybe you have a bad amp gauge and things are running fairly normal?

I just looked at the 66 shop manual and the way they show the ammeter doesnt make any sense. They show one side running to the battery side of the starter relay and the other wire to the battery side of the alternator with is also connected to the same terminal of the relay.

I'd install a voltmeter and monitor the battery voltage under various loads. Check it at idle with no accessories running. You should have between 13.3 and 14.4v at the battery. Turn the brights on and the voltage should drop slightly, but not by much. Keep turning things on until you see a good voltage change. If it stays relatively steady the whole time, I'd have to suspect a bad amp meter.

One good thing to do is run a 4 gauge wire straight from the output of the alternator to the positive battery terminal. Next, run a 4 gauge wire from the negative terminal to a good solid ground on the engine. I try to get it as close to the alternator as possible. If you want to go further, run an 8 gauge wire from the positive battery terminal to the input of your fusebox. That should eliminate any voltage drop through the usually borderline wiring harness in stock vehicles (ESPECIALLY older ones). Even though your harness is new, I'd suspect it's similar to stock.

As an example, my '79 Caprice was losing almost 3 volts from the alternator to the battery (through the stock wiring). The alternator was putting out ~17 volts and the battery was seeing 14v. With the 4 gauge wire, the voltage drop was unmeasurable. The lights stayed bright at idle and all of the accessories ran better.

Could you provide a link to the regulator that you are using? You could wire the regulator up directly to the alternator using jumper wires to make sure you don't have a harness problem. I'd run through those tests before doing that, though.

Pinhead":1r7b7gcb said:

I'd install a voltmeter and monitor the battery voltage under various loads...

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Definitely. You cannot properly troubleshoot this type problem without a good voltmeter. I would much rather have a voltmeter than an ammeter any day.
Joe