Ok,

replaced my alternator today with the exact original that came with the conversion - 77 Lincoln Versailles 302...now the thing is that I also changed out the voltage regulator as said by the company 65 amp alt with a 61 amp voltage regulator...so when i changed it all out, my voltage meter is only registering between 11-12 volts...i have a BRAND new battery from autozone (gold series)..before my old alt was toasted, i was in the 13~14 band area...what is going on gentlemen??? ...i did do a hot wire set up to the battery straight to the alternator due to running two amplifiers and radio...

 

Based on my truck's history, I was pushing 11-12 volts when my alternator was crapping out. I don't know what amps it was pushing out, but when I installed a 100 amp alternator, the voltage went up to 13-14.

My guess is that your old alternator was pumping out a lot more than 65 amps.

BTW, my setup is a one-wire alternator and no voltage regulator.

 

You may try taking it back to autozone and trying a different one? It seems that the quality controll on the remanufactured stuff is sometimes low.

 

With the engine running, try unplugging the connector from the voltage regulator and using a jumper wire 'full field' the alternator. This should cause the alternator to jump to 15+ volts. If it doesn't, give it a little revv. If it does go up to 15 by revving it a bit, you may have one of the diodes going bad.
If it doesn't move at all (above your initial readings) then the alternator is most likely toast. Doubble check your wiring and grounds (broken and whatnot) to be sure.
Now if it does shoot up to 15+ volts, then you have a good alternator, and now I'd be suspect to your voltage regulator. Be sure you have it grounded well. I don't have any tests for it other than swapping out and 'testing' your skill at hitting the trashcan from afar. (if another new one fixes the problem of course)

Here's a pic to explain which terminals to jump-

 

okay swapped out the alternator for a duralast...pulled my battery cable off and the truck dies...never done that before unless the alt was bad...now i have checked-rechecked all the wiring...still only gettin 11 volts on the ammeter...now the ? for today..could my gauge be bad? could the MSD 6A be done or the coil? I am not electrical smart on this stuff.... H E L P!!!!!

 

Ok.. lets look at this. First off, just pullin the batt cable off isn't gonna tell you much of anything that we don't already know. The charging system isn't working and that's why the engine keeps dying. Doing the above test i suggested would isolate 1 of 2 components that would cause the problem.
Since you have swapped out the alternator (i assume you made them test it before you walked out of the store with it) this really only leaves one other main component. The voltage regulator. There are some tests that you could do, but i normally just swap out one for another (that is a known good one) and see if that improves the situation. Make sure that the voltage regulator has a good ground. They are typically grounded through screws, to the metal panel that they are mounted to.

Also- where are you getting these 11 volt readings from? Hopefully not a gauge in the instrument cluster. these can be inacurate at times. I like to use a multi-meter or an engine tuning analyzer (usually reads RPM, Dwell, charging sys voltage, etc) and take the readings directly off the battery posts. Do you have either of these at your disposal?

 

i sure dont but i know where i can a multi-meter from....also its crazy because the old alternator was running the truck fine....no i did forget to mention that i am running MSD 6A on the system that shouldn't be a problem since the truck does start right? Also, i had to redo the wiring on the alternator because the shop had a funky setup...was running a power right straight throught the voltage regulator instead of the battery...also is it possible that a spark could have fried my gauge to read incorrect? trying to research ALL options before i start slicing up this EZ-wire harness!!!

 

Well there's a thought here. It's possible that when you re-did the wiring that you may have got things hooked up backward. Without seeing a picture(s) or seeing a diagram of what you have there it's tough to say offhand what's going on. But piece by piece we can figure theis out.
And no, your MSD should have nothing to do with your issues. Your truck will start and run because the ignition is still feeding power from your battery. We are just not able to put a charge on teh battery (or system) for that matter which is why the truck dies when you pull the battery cable.

Here's a quick sketch (pardon the crude chicken scratch) of how the charging system should be set up. There are actually 3 different ways, but this is the most common for non-factory street rod applications. Of the other two ways, one would incorporate a Ammeter and the other an idiot light.


Ireguardless of the size of the alternator this is how it should be wired up. Obviously later model and/or larger capacity 70s and up alternators will look a bit different, but principles are the same. Check this schematic against what you have. If you have a test light, that will be useful to find your flow of electricity to make sure we've got it going in the right direction to the right places, in order.

Unplugging the 4 prong connector from the regulator, with the key off, probe the connector. All 4 prongs in the connector should be dead. Now turn the key to the 'run' position. The 'A' terminal of the 4 prong connector should be hot. If the connector has a jumper wire to the 'S' terminal, that obviously should be hot too. Go ahead and plug the connector back into the regulator. Now from the bottom of the connector (where the wires go into the connector itself) probe the 'F' terminal. This one should now be hot, with the key still on. This is the regulator energizing the 'field' of the alternator to allow it to charge.

Also check the wires on the back of the alternator up against the diagram I posted. If you can't see the wires (if its taped up or in a loom) use a multi-meter, on ohms, (disconnect battery for insurance) and set it to 'beep' when you complete a circuit. Test your meter by touching the two leads together before probing. Should 'beep' or if not aboe to make sounds, it will display a '1'. Probe the wires at their corresponding terminals, isolating the path of each wire. If you're not getting a completed circuit (a beep or a '1' showing), then you've got some wires backwards or wrong.

See if this helps, and let me know.

 

I don't know what you have but you have been given good info, so do the test suggested. The other thing is you said you are reading 11 volts on your amp meter, amp meters don't read voltage, what is it you have a volt or amp meter?

 

You won't be able to do much electrical diagnosis without a multi meter.

Here's one at Summit for $11

Performance Tool W2974 - Performance Tool Digital Multi-Testers - Overview - SummitRacing.com

With that you can check the battery voltage before starting and with the engine running. I'm not sure what you're checking by disconnecting the battery cable with it running.

You should try Dano's trick to jump a wire from the battery to the field....with your voltmeter attached to the battery + post to see if the alternator output voltage jumps up.

You need to start thinking in terms of finding the problem by isolating problems.

I'm not sure about Autozone, but many auto stores test alternators, but without a load, so you still won't know if it's fully functional....as in, in a bench test, if only one or two of the three sets of internal windings are working, an alternator will put out voltage...as long as there is no load...once you load it, the voltage output will drop off.

What you really need to do is load it up with all of the lights, and stereo, heater blower etc. and measure the voltage output.

Dan

 

borrowed a friends multimeter tonight...battery is at 12.85 volts...going to rewire my everything by the sketch since i had the shop do my truck, my batteries have been dying and this might be the reason why...i will keep you all posted in this thread..

 

okay so when the truck is running with lights, radio, amps - 12.13 dc volts...still though the truck cuts off when the battery is disconnected...now i know that a 1977 Lincoln Versailles engine with a 1985 Mercury Cougar Alternator has more amps but come on man...i should be at least 13 when running (brand new autozone gold series battery)...i think the gauge might be messed up or the voltage regulator...the one i have is not in the system anymore at Autozone so i am wondering what was i allowing the system to charge with...also the shop had the alternator (battery power) wire coming straight to the voltage regulator instead of the battery-alternator? was this correct to maintain power in the system when running without battery power? charging system is killing me but I WILL ADMIT - I AM LEARNING....HELP ME PLEASE!!!!!

voltage regulator #4179J23 can anybody tell me what this one allows please!!!!

 

could you give me the other two ways for wiring please...

 

If you pull the battery lead off while the engine is running, the engine will die. Sometimes the system has enough capacitance to keep the alternator field energized for a little while, but normally that's what a battery is for.....so pull the battery lead...engine dies....everything normal there and it won't tell you very much about what part of your system is malfunctioning.

Start here:

Test the voltage of the battery with everything off.

Have a helper start the engine while you keep the voltmeter on the battery (truck in neutral!!!)....the battery voltage should drop while the engine is cranking, then after it starts, if the alternator is working, the voltage should go to something higher than the battery voltage that you measured before starting...say...around 13.5 to 14 volts.

If what you end up with while the engine running is a battery voltage that is slightly lower than it was before the engine start, then the charging system is not working. The voltage is lower because the ignition system is drawing power, so the battery voltage will read slightly lower.

If that is the case, check the voltage at the alternator field (still running)...it is supposed to be something greater than zero. If you have basically no voltage (or something very low), try Dano's test....shut off the engine for a while.... & disconnect the field connection from the alternator. Get a piece of test wire & carefully hook one end to the field connection on the alternator. Re-start the engine. Attach the volt meter to the battery (have your helper hold the test leads on the battery posts). Briefly attach the other end of your test wire to the battery positive post & observe the voltmeter (you are momentarily providing full battery voltage to the alternator field). If the voltage on the meter goes up & you hear the alternator load a little, the alternator works, and the voltage regulator is the culprit (or maybe the wiring for the regulator)...the voltage regulator is supposed to be providing power to the alternator field.

If nothing happens when you attach the field test wire to the battery, the alternator is suspect....remove it and have it tested at the local auto parts store....even the no-load test that they do is better than nothing.

Try those tests & keep us posted!!

Dano's wiring diagram looks accurate, so use the multimeter to track down the problem!!

Dan

 

James,
You are right in that by disconnecting your battery with the truck running and it dies the charging system is not working, but you need to do it with all the other electrical loads turned off. Granted it is not he best way for testing your electrical system but it is an easy way when you have limited electrical experience. The vintage of the engine/electrical system you have in your truck would act as you are describing.

As your truck is not stock anyway I would highly suggest going to an aftermarket one wire alternator form some place like Summit Racing, you can get there branded ones for $100 or less. You bolt it in, hook one wire from the alternator to the battery and you are done. It really cleans up the wiring in the engine compartment as a nice bonus.

Keep us informed which way you decide to do things and if you re-wire the system let us know how you do it incase you still have issues.