Are these symptoms of a bad voltage regulator?

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Are these symptoms of a bad voltage regulator?

Postby pookster » Thu Aug 30, 2007 11:48 pm

So ever since I bought my car every time I started the ALT light would be on until I revved the engine a bit then it went away. Then the first time I took it on an hour long trip on the freeway it ran fine, but the next day it wouldn't start unless I jumped it and then it wouldn't start the next day, unless jumped again, and this was all on a fairly new battery and alternator. Come to find out the battery needed a good drink of distilled water. After that everything went well for a couple more years, but I didn't take it on an long trips. Then recently I had to take it on that same hour long trip on the freeway. For a couple days after it ran fine, then just tonight it wouldn't start, and of course the battery needed some water. So I filled her up and jump started and got home. I am not sure but I am betting it will start just fine tomorrow. Also, when driving at night while idling the lights are dimmer than when cruising. So my question are these signs of a bad voltage regulator?
Thanks
Mike
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Postby fordconvert » Fri Aug 31, 2007 10:37 am

The battery loosing water is usually a sign of an overcharge. Its not uncommon for some alternators to need the initial rpm boost to get going after the demand of starting the car but once you rev it that first time it should 'stay online' the rest of your trip. There are also aftermarket alternators that dont turn on till they get to a specific rpm. These are usually called 1 wire and have an internal regulator. The regulaors are cheap enough that it may be worth a swap to see if that takes care of your problem. A voltmeter would also be a handy tool for this. It does not have to be digital but a small cheapo analog one may be hard to read. Just hook it anywhere in the system like the battery. It should read around 12.5 with a good battery and the engine not running. Engine running should be 13-14 ish. If its at or above 15 for any length of time its going to be hard on everything including the battery. Under 13 is not going to be charging very fast. Turning on the heater fan and headlights shouldnt change the reading much. Higher RPM's also shouldnt make a huge differnce other than at low rpms with a large electrical load like a weak battery, heater fan, ect... It should only take maybe 10 minutes of normal driving or driving rpms to more or less get things back to the normal range. You can also find a lighter adaptor (off an old cell phone?) and rig up the meter so you can have it in the car with you while you drive and see whats going on. If/ when you replace the regulator check to see that the connections are clean, most of the time you can jam a little flat screwdriver in the slot and pull the contact out of the block to clean and inspect it. Also many of the Ford ones ground through the case so make sure the area it bolts to is clean at least around one of the bolts. If the voltage does not change at all with the engine running the alternator is not coming online for some reason. I had an F150 that had a bad joint at a fusible link in a harness between the alt and the regulator. Took a while to find it but after I fixed it never had another problem.

Many parts stores will test all that stuff for you if you take it off the car.

Another thought, check your grounds. When you jump it are you going ot the - on the battery or somehwere else?? If you are going to the battery it may be ok but if you are going somehwere else maybe you have a bad ground strap and the jumper cables are just adding a ground?? Take jumper cables and just hook the engine to the body and battery and such. See if that changes anything.
TJ H

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Postby fb71 » Fri Aug 31, 2007 1:00 pm

is your reg still the original type? (can is about 2 inches tall)

if so, then yes, I would suspect it. They're electromechanical regulator, relying on current-sensing relay and points to regulate voltage. The points often stick as they age, either off or on. Your symptoms indicate its sticking on. Change to a $15 solid state type (short can, about an inch), available from any chain parts store, and see what happens. Its plug-and-play, so you don't need to modify anything. If they don't list one for a 65 Stang, tell them its and 81 Stang, same regulator.
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Postby pookster » Fri Aug 31, 2007 2:37 pm

A few updates:
For explanation the alt light goes off after reving the engine for a second.

And my assumptions that the car would start this morning failed!! I thought the drive home (a good 5-10 mile drive) would charge the battery, but I guess not. The headlights were on so maybe it didn't get charged like it should. But I cant think of any ideas of why the battery was dead this morning. Any Suggestions??

Also one thing I failed to mention (this might be a starter problem) but when I start the car in the morning it cranks fine and starts up good. Also after an 8 hour day it cranks fine too. But if the engine is warm and I stop at a store for a few minutes then try to start, it cranks like the battery is low. What I mean is it cranks just barely then just for a sec nothing (not cranking) and then it fires. Like I said that might be a starter, but any suggestions.
PS my biggest concern right now is the battery being dead. I dont know if the regulator is new or not.
thanks
Mike
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Postby Lazy JW » Fri Aug 31, 2007 3:11 pm

If that is the same battery that has been run low on water several times then it may well be in need of replacement.

Make certain that the alternator belt is in good condition (not glazed or cracked) and that it is properly tightened.
Joe
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Postby addo » Fri Aug 31, 2007 4:15 pm

I'm with Joe on the suspect battery.

Heat kills more batteries than cold, a battery guy told me (but cooler weather shows up the weak, old ones).

Load-test the battery on a proper testing machine, and it will likely be found wanting. The alternator/regulator setup should also be properly checked, in case they contributed to the battery's demise last time (overcharging).

Interested to see opinions here that the mechanical regulators are dispensable. Generally, I'd look for an old-timer and get one adjusted.
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Postby pookster » Mon Sep 03, 2007 8:32 pm

An update on my electrical woes does not reveal good times ahead like I had hoped. But I still need your help with this one. So Friday night I went to autozone and picked me up a voltage regulator, I threw her in and much to my surprised my car turned over and started right up. So I drove it around the block a little bit to give the battery a little juice and I thought it was all well. Then I come out the next day and she wont turn over again. I thought maybe I just didnt drive the car enough to get it charged. So I jumped it and made my journey (about 40 miles). Got to my destination turned it off and tried turning it on 5 minutes later and once again it didn't turn over!!! So I was upset, but I went camping, came back, got it jumped and measured the voltage, and it was 12.3 right after I jumped it. I drove it home took it to autozone had them test it and it was running at 16.3 volts!!!!! So it is being way overcharged. So I figure once again my voltage regulator is bad, but what is causing it to go bad like that???? Oh, and while the car was running the guy at autozone put a load on the battery and it died, so that indicated a bad battery. But I dont want to replace the battery if it is just going to get destoryed again.

After all that explanation my question is: What is causing my voltage regulator to die so quickly? What about the battery and other such issues.
Mike
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Postby fordconvert » Tue Sep 04, 2007 9:31 am

Do you have a known good battery you could swap in to test? If you are getting a marginal quality regulator(s) (which could be all thats out there now days) and your battery is really bad it could be overloading the regulator right away. Do you have a battery charger? See if the battery will take a full charge that way so the alternator does not have to do anthing other than recover from starting. After a long cranking period 14 ish volts for a minute or two wouldnt bother me much but that 16 you saw was way high. Did you check all your grounds? A poor ground between the regulator, alternator, and battery could confuse the regulator. Do you know if you are getting the modern electronic ones or the old style electro mechanical ones? Im not even sure if they offer both or how you would tell without bustin them open.
TJ H

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Postby addo » Tue Sep 04, 2007 5:51 pm

I was partially right. The battery was bad - not surprising given the age and other factors.

Now I also suspect the alternator diodes are partially faulty - giving an uneven waveform output which is not being effectively regulated.

Normally, I would check these diodes myself with a meter, but have heard this doesn't always expose deficiencies at working load current strengths.

Also to check in the alternator would be continuity/resistance of all windings.

Regards, Adam.
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Postby 66 Fastback » Wed Sep 05, 2007 9:55 am

Another possibility is that you could have a electrical short / leakeage somewhere that is not big enough to blow a fuse or take the vehicle down completely. I once had an intermitteant short that was causing the generator and regulator to pour the juice to the battery. The water was boiling off the battery and I suspected the regulator as being bad. Turns out I had an intermittant short on an unfused circuit and it was overworking all of the electrical components.
Doug
Last edited by 66 Fastback on Wed Sep 05, 2007 1:42 pm, edited 1 time in total.
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Postby Lazy JW » Wed Sep 05, 2007 10:58 am

pookster wrote:...After all that explanation my question is: What is causing my voltage regulator to die so quickly? What about the battery and other such issues.
Mike


Well..... the simple answer is: I dunno exactly :oops:

This type problem is sometimes difficult to troubleshoot first-hand; and ever-so-much-moreso from long distance. You REALLY, REALLY need to aquire an inexpensive DVOM (Digital Volt, Ohm, Milliampmeter) and get aquanted with its use.

Then we can walk you through the very basic tests that we would do if one one of us were standing there. The first thing I would want to know is what the battery voltage reads first thing in the morning before startup.
Joe
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Postby 66 Fastback » Wed Sep 05, 2007 1:52 pm

After all that explanation my question is: What is causing my voltage regulator to die so quickly? What about the battery and other such issues.


So have you replaced the battery? A bad battery with an internal short will cause the regulator to work overtime to try and charge it and could cause it to fail.

I think the Number One rule is to have a good battery first. If the battery is not up to snuff, then you are chasing your tail trying to diagnose other components in the system. I think most manuals say the battery should be fully charged and in good condition before diagnosing other electrical problems. You are trying to see if the components act normally. A discharged battery with a fault in it makes everyting behave abnormally.
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Postby ludwig » Wed Sep 05, 2007 2:27 pm

I think most manuals say the battery should be fully charged and in good condition before diagnosing other electrical problems. You are trying to see if the components act normally. A discharged battery with a fault in it makes everyting behave abnormally.


Amen 66 Fastback. Even if the battery is new or relatively new it can have an internal short AND it can drain down as quickly as five minutes. I just get a new battery when I have squirrely electical problems. You can get a decent battery with a one or two year warrenty for like $50.

Keep the old one and put it on a trickle charge while you are fooling with the bugs in the car using the new battery. If it doesn't hold a charge, junk it or take the old one in to the part shop and have them test it.

You can test if you have an electrical leak by detaching one of the terminals and holding it a short distance from the post to see if there is a small spark. Of course, the clock or some internal memory in the radio could cause a little spark so disconnect these.
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Postby pookster » Sat Sep 08, 2007 10:41 pm

Sorry it took so long to get back but I had to park my mustang and the grandparents house for a few days, but I got some more info on this problem.

I took the car to my grandpa and he tried charging it, and it wouldn't accept a charge. So the battery was dead. Without me knowing he replaced the battery and now it starts up fine. So I got my handy-dandy multimeter out and tested the voltage at the battery with the car off after I drove it for 5 minutes. It read 13.4 volts. Thought that was high for the car being off. So I left it off for a couple of hours went back out and before I started the car I tested it again and it was at about 12.4. Drove it for another 8 minutes parked it and with the car on I tested the volts and it was 17!!!!!!!!!!!! Way too high.

So I think I have a 30 day guarantee on the voltage regulator, so I will try replacing that, and see if that fixes it. But remember I just replaced it. So I am wondering if the bad battery destroyed the voltage regulator, or is there something else I should be suspecting that damages it?

PS I have a digital multimeter so is there anything I should test?? I dont know much about using it or testing electronics in the car, so if there is something I should test could you explain it in the simplest way possible.
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Postby Lazy JW » Sat Sep 08, 2007 11:50 pm

The only thing that can make the voltage go that high is the regulator. I don't believe the battery caused it to go bad either. Once you've made all the usual ground cleaning checks, etc. there isn't much else to do but replace the regulator. Or get an Optima battery.
Joe
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Postby addo » Sun Sep 09, 2007 3:16 am

What about a bad diode, causing an irregular output waveform? I'm thinking of something that could tax the voltage regulator beyond its ability.
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Postby fordconvert » Sun Sep 09, 2007 10:03 am

Anybody know what the typical regulator is now days? Electro mechanical or solid state? I would assume the concourse fomoco one is still mechanical but would suspect that the store brand ones are solid state. I bought one for a tractor that was solid state but still came in the big can. Dont know if that was a tractor thing or just the way they make em now.
TJ H

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Postby pookster » Tue Sep 11, 2007 12:53 am

Things arent going so well. I went down to autozone and after giving me a little bit of guff they replaced the voltage regulator for free, it was fried. But unfortunately with the new one it the car is still running at 17 volts!!!!! So how long can my battery take this? I have to drive 15 minutes to and from work every day. So if I watch the water level in the battery will I be ok for now? Also, where do I go from here? What do I look at for problems? A couple of you said grounds. What do you mean? Look for loose wires and bad connections or is there a better way? I have a multimeter so if there is something I need to check just tell me how and I will.
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Postby ludwig » Tue Sep 11, 2007 1:05 am

Do you have a generator/VR setup or an alternator. Because if you have he genereator/VR, they have to be replaced as a set, both at once. You have to polarize the VR once they are both in by brushing the positive lead and the negative lead of the VR with a small wire before firing it up. It's just a touch, not a big jolt of elec. If you don't, you will be replacing one then the other in an endless loop.

Not kidding here. Check the link.
http://web.utk.edu/~tprather/FoothillsT ... rator.html

Although it's for a tractor, the principle is exactly the same. Alternator/VR is a different story.



If you are testing generator output right after startup, then it will be high to replace the drain caused by the starter. A little later it settles down to the 12+, somtimes 13 that keeps the battery topped up with juice.
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Postby Lazy JW » Tue Sep 11, 2007 8:48 am

Good point Ludwig,
In his original post he wrote the ALT light comes on. If this vehicle has an alternator then it needs an appropriate regulator.

DO NOT EVER attempt to polarize an altenator system! :twisted: :twisted:
Joe
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Postby 66 Fastback » Tue Sep 11, 2007 10:06 am

Is your multi-meter accurate?
However, it sounds about right with your fully charged battery reading of 13.4 volts. Contrary to your comment about that being too high, a new 12 volt battery should have about 13.2 volts at full charge.
I have some cheap meters that read a volt or two different from my better meter. You might see if a someone else or autozone can slap a meter on it and verify the voltage.
Doug
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Postby addo » Tue Sep 11, 2007 10:12 am

Pookster, pull that alternator down and check it with your "handy-dandy multimeter". Resistance for every winding, and check all diodes.

Trust me. :wink:
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Postby 66shelby » Wed Sep 12, 2007 4:11 pm

Recently had a similar problem, but the tools to check properly. Turned out I had a bad winding in the starter. This killed the battery which then killed the voltage regulator. Alternator made it thru OK.

I would suggest that you hook up your meter to check voltage drop while starting the car. My fully charged battery would read 12.3 volts, but would drop to 7.5 while cranking. 10 volts may be acceptable but anything less and you have a problem.

The Zone can check about any starter or alternator on their bench. Even Walmart can check your electrical system. Trick is to find someone experienced enough to really be helpful.
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Postby pookster » Thu Sep 13, 2007 1:09 am

Took my car to the local autozone to have my alternator tested and to check the voltage to see if my multimeter was reading right. They say that the alternator is fine, and they also got the reading of 17 volts like I did. So should I still check the windings in the alternator, or what. Also, how long can I keep my new battery going like this until I really start doing some damage, or will keeping the water full, keep the battery from being destroyed?
Thanks
Mike
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Postby fordconvert » Thu Sep 13, 2007 10:07 am

If the level is droppin in the battery it loosing more than just water so you will be hurting it. How fast I dont know but long term it cant be good.
TJ H

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Postby Lazy JW » Fri Sep 14, 2007 12:17 am

I had a GMC pickup that always charged over 17 volts. It boiled the battery something fierce; after the second battery went bad I bought an Optima and lived happily ever after.
Joe

PS. That works if the ONLY problem is excessive charge voltage.
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Postby addo » Wed Sep 19, 2007 7:14 pm

Was the problem ever resolved?
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