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Re: voltage regulator [Re: stateroadhog] #1863480
07/04/15 01:02 PM
07/04/15 01:02 PM
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Owosso, Michigan
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stateroadhog Offline OP
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Okay ran jumper wire from alt case to regulator. Same thing shows 14.2 at + coil if meter is ground to body, shows 20 volts if grounded to motor. alt case to body shows 4 to 5 volts. alt output stud to starter relay stud shows 8 volts. Battery shows 14.2 charging all with car running.

Re: voltage regulator [Re: stateroadhog] #1863512
07/04/15 01:41 PM
07/04/15 01:41 PM
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Originally Posted By stateroadhog
.....alt output stud to starter relay stud shows 8 volts.....


8 volts? Holy crap, Batman. What I would recommend you do now is run a jumper between the alternator output stud and the starter relay and redo the readings. If the voltage difference from the alternator to the starter relay is now near 0 volts you have a poor connection in the wiring from the alternator to the starter relay. Biggest question at this point is do you have the stock ammeter? The stock charging circuit goes alternator to bulkhead terminal, bulkhead terminal to ammeter, ammeter to bulkhead terminal, bulkhead terminal to starter relay. If the jumper between the alternator and starter relay worked, then you have a poor connection somewhere in the above path. If you have eliminated the ammeter, then you will have to determine where a poor connection may exist based on how you modified your system. The other voltage between the alternator case and body should wait on what you find out with the above tests.


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Re: voltage regulator [Re: stateroadhog] #1863528
07/04/15 01:54 PM
07/04/15 01:54 PM
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stock ammeter but solid wires to and from not threw the bulkhead connecter. Next wierd thing, I still have jumper wire from regulator to Alt case, when measuring voltage with the DVM red lead on + coil ground on jumper wire at Alt reads 20 if I move ground to jumper wire clipped on regulator it reads 14.2 how is this possible on same wire? 1 of the readings has to be wrong. If I have been running all this time with 20 volts to coil and electronics I got to believe it would have fried something by now.

Last edited by stateroadhog; 07/04/15 02:09 PM.
Re: voltage regulator [Re: stateroadhog] #1863564
07/04/15 02:30 PM
07/04/15 02:30 PM
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Quote:
If I have been running all this time with 20 volts to coil and electronics I got to believe it would have fried something by now.
Agreed, can you borrow another meter from someone for an hour, preferably an analog? or at least another digital. EDIT I suspect you are actually at 14.2 (high end but good) & for some reason the meter ain't stabilizing (poor connection/bad meter).

Last edited by RapidRobert; 07/04/15 02:58 PM.

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Re: voltage regulator [Re: stateroadhog] #1863573
07/04/15 02:46 PM
07/04/15 02:46 PM
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Owosso, Michigan
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Thats my next move something is just not right. I hooked up again to my sons Nova with MSD ignition it again shows 25 volts on + side of coil. To many conflicting readings. I Thanks everyone for all the help. Holiday weekend everone else at track Maybe can borrow meter tomorrow.

Re: voltage regulator [Re: stateroadhog] #1863576
07/04/15 02:53 PM
07/04/15 02:53 PM
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I missed the comment you made about "...flash on meter...". After being misled by more than one digital VOM, I quit using them for general automotive use. Strictly analog for me.


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Re: voltage regulator [Re: stateroadhog] #1863755
07/04/15 06:51 PM
07/04/15 06:51 PM
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The MSD doesn't work like other ignitions, I'd only be concerned with voltage readings at the battery.


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Re: voltage regulator [Re: John_Kunkel] #1865245
07/06/15 05:19 PM
07/06/15 05:19 PM
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Basic facts...The Pertronix III is a multi-spark ignition. That makes the hot wire between the module and the coil part of a resonant system and voltages you measure across the coil are meaningless.

The MSD6 is a capacitive discharge system and the capacitor hits the coil with tiny bursts of high voltage, somewhere around 450 volts, one hit for every spark. When you put a voltmeter on that it measures the "sorta" average voltage. Again, meaningless.

I have run the 732 "Race only" voltage regulator on the street since 1984. It's the same internally as the 731. There is nothing inherently wrong with either regulator. My charging voltage measured across the battery terminals is roughly 14.3 to 14.5 volts, just what a modern maintenance-free battery likes to see. Some have suggested it's race only because it does not bias charging voltage to the temperature. Could be, but it is meaningless as well because it just flat works. My batteries last, on the average, 7.5 years. One thing this regulator did is keep enough charging at idle that my headlights do not act as a visual tachometer any more.

Grounds are very important and need to be policed every once in a while. Also, the suggestion to ground directly to the alternator case or the battery negative post is right on.

Finally; when someone shows up with a "problem" the first thing to do is analyze if it really is a problem. Everyone jumping on their horses and riding off in all different directions does nobody any good. The stock answer to buy a new one doesn't help either, not until the real problem is identified. In some cases the best suggestion would be to get different friends, if the friends are terminally ignorant. (Especially Chevy Know-it-alls.)

Warmest Regards,
R.

Re: voltage regulator [Re: stateroadhog] #1865721
07/07/15 09:32 AM
07/07/15 09:32 AM
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Owosso, Michigan
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stateroadhog Offline OP
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Agreed I am begining to believe I real do not have a problem. I re-did all the grounds added extra ones and nothing changed.Like I stated earlier if I was really seeing 20 volts the system would have fried along time ago. I have also run this 732 regulator for 20 years with no problems. I think the 40 year old dash harness doesn't help either. The bullet connecters to ignition switch are old and brittle. I have hard wired several of them. I still would like to thank all who chimed in to help with this problem.

Re: voltage regulator [Re: stateroadhog] #1865747
07/07/15 10:39 AM
07/07/15 10:39 AM
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Originally Posted By stateroadhog
.....alt output stud to starter relay stud shows 8 volts.....


An eight volt drop? I don't care what kind of ignition you have, this doesn't sound right. Either there is a problem with the multimeter and there is no wiring problem or there is a legitimate wiring problem. May be some of both but to walk away with the conclusion that I haven't smoked anything yet so I must be OK..... shruggy


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Re: voltage regulator [Re: stateroadhog] #1866406
07/08/15 08:49 AM
07/08/15 08:49 AM
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Not walking away from analizing problem. Just need to regroup and give it more thought. I know something isn't right. Looking at 40 year old wiring.

Re: voltage regulator [Re: stateroadhog] #1866425
07/08/15 09:56 AM
07/08/15 09:56 AM
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Originally Posted By stateroadhog
Not walking away from analizing problem. Just need to regroup and give it more thought. I know something isn't right. Looking at 40 year old wiring.


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