Generator issues-

[ledfootslim]

Well,first off, I know this has been discussed before, but I couldn't find where anyone explained the solution to my problem: My 1948 Desoto S-11, six volt positive ground, 236.7 CI engine, is not re-charging the battery. It sputters and loses power at high rpms, generally at about 35-40 miles an hour, which made me think of the vacuum advance, but when I pulled the cable off of the battery post, the engine always dies, so the car must be running off the battery power rather the electrical system. I have to charge the battery before starting, especially after a drive. Using a test light, I have no power going to either post on the generator- should one of the wires be hot, and if so, which one? Could this problem be the voltage regulator? I had the generator re-built professionally a few months ago, but I may take it back. As soon as I turn my key on, the ammeter drops below negative, and remains there, dropping even lower with the lights or anything on. I hope somebody can offer some advice, cause I'm stumped! Thanks!

[Plymouthy Adams]

I suggest you do follow the testing procedure outlined in the factory car manual...it is a quick way to ensure your charging system is up to the task..In the absence of a repair manual you going to make some assumption and guess-timations...if you don't have the book it is by far on e of the best investments one can make to support their car..in the meantime, maybe someone here could scan and paste the pages for you...

 

so do the tests, be sure what is wrong before you write that check..

[janan5243]

I believe there are several threads an the forum about testing the generator & regulator. If you do a search for "generator" from the main page of the forum it should bring them up. Plymouthy is correct. You should get a PAPER copy of the shop manual. There are several places on the net & E-Bay. First thing I bought for my car. It will have all the factory procedures & tests. Good luck. It definitely sounds like the generator is not charging system. I had similar experience years ago with a pickup. Cost me lots of money to discover that I had too many lights between truck & trailer for the generator to supply. Could not get truck over 35-40 mph at night. Ran fine during day with no lights on.

Edited September 12, 2014 by janan5243

[ledfootslim]

I went ahead and ordered a paper copy of the manual- the digital one I had was a pain in the seat-meat. I dug through previous posts for about an hour, and didn't feel like I got any smarter-   I don't have a multi-meter or voltage meter, so I'm not sure about testing it. The electrical system is my weakest point......................

[Plymouthy Adams]

A VOM is not that expensive and an asset in troubleshooting the electrical system..get a higher quality one and compatible amp probe

where 1 mil equals 1 amp and be able to truly test your current draw and output plus other elements of the electrical system..

[Jeff Balazs]

You won't be sorry about having the manual. I agree with many others.... a paper copy is much easier to use than digital format. And you can make foot notes in it for future use.

 

I would also recommend you purchase a decent Multimeter. It really is a good investment for your toolkit. I have an old Craftsman unit that I have had for years. Saved the day many times. Most of these have a booklet explaining how to use the various functions. Learning to use this tool is like anything else.....takes some effort but well worth it. For older vehicles like our trucks pretty much everything is simple once you have studied up on in a bit. And of course if you get stuck there is always first class help here. It's funny but a lot of folks seem to have some trepidation about working on electrical stuff.....but if they get past that they will find that it is a very useful skill set to have. Just as rewarding as any other skill. You will be surprised if you take the time to master it just how often you will be a hero!

 

Jeff

[DJ194950]

If your going to continue working on cars I'd suggest buying a decent(but not to expensive) multimeter. Harbor Freight has one similar to the 2 - I bought about 10 or more years ago. Work great and had a chance to compare to a Big name brand one ($500 +) once using voltage and resistance readings NO difference!

Now sells for about $25 at HF  online if not one in your area.

 

Think if the car were mine I'd charge the battery and drive it to the place that repaired your generator and tell them it's not working. Sure they will test it on your vehicle to prove you wrong, but in their test they will tell you it's the VR or wiring! Usually free as most stand behind their work, (I hope!). Might even have a replacement VR if needed. Then change it and test (no free ride here).

 

Best to ya,

 

DJ

Edited September 13, 2014 by DJ194950

[ledfootslim]

If your going to continue working on cars I'd suggest buying a decent(but not to expensive) multimeter. Harbor Freight has one similar to the 2 - I bought about 10 or more years ago. Work great and had a chance to compare to a Big name brand one ($500 +) once using voltage and resistance readings NO difference!

Now sells for about $25 at HF  online if not one in your area.

 

Think if the car were mine I'd charge the battery and drive it to the place that repaired your generator and tell them it's not working. Sure they will test it on your vehicle to prove you wrong, but in their test they will tell you it's the VR or wiring! Usually free as most stand behind their work, (I hope!). Might even have a replacement VR if needed. Then change it and test (no free ride here).

 

Best to ya,

 

DJ

Well, that sounds like a good idea, but I can barely make 35 mph, and the shop is half an hour away. I tick people off just driving slowly down the dirt roads, they might draw guns if I crept down the highway at that speed! :-) And, I will pick up a multi-meter the next time I hit Fayettville- should prove useful!

[_shel_ny]

Even a $3 (sale/coupon price)(sometimes free with purchase coupon) HF meter will be helpful. You may not be able to do high amp stuff, but it will do the basic stuff. And if you hook it up wrong, drop it, run over it, your only out $3.  I stuck the leads in the ac outlet with one on amps instead of volts. Poof, but just a $3 poof.

[austinsailor]

Correct me if I'm wrong (I'm 1000 miles from my cars), but isn't the big lug on the generator hot all the time? If you have nothing there it puts you pretty much on the problem.

There isn't much you can do with the electrical system without a meter. As mentioned, harbor freight starts at $0.00 with a coupon, (no purchase necessary - i just got another last week) under $10 always, usually $7 on sale, and even Wally World has one for around $12.

A fancy one can do just a little more, but a cheap one will do about anything most of us ever needs. Do we need to measure micro volts? I doubt it. I have half a dozen laying around. I still have trouble finding one when I need it! And when I break one I don't have meltdown.

You gotta get some sort of meter.

Edited September 13, 2014 by austinsailor

[Don Coatney]

I like my Fluke

 

[TrampSteer]

Love those flukes. Can't afford them.

[DJ194950]

Well, that sounds like a good idea, but I can barely make 35 mph, and the shop is half an hour away. I tick people off just driving slowly down the dirt roads, they might draw guns if I crept down the highway at that speed! :-) And, I will pick up a multi-meter the next time I hit Fayettville- should prove useful!

If you can't get over 35mph with a fully charged battery, something else is also going on.

A multi

meter wont most likely help with that!

DJ

[ledfootslim]

If you can't get over 35mph with a fully charged battery, something else is also going on.

A multi

meter wont most likely help with that!

DJ

That may be, but I know that she should run with the battery unplugged, and should keep a charge, so Im gonna solve this problem, and then start on the next one. And I believe there was recently some discussion about the same problem I have, and the general consensus was that if the car was having to run off the battery's power, that at higher rpms, it would lose power and sputter and cut out like mine is- so maybe I'll kill several birds with one stone!

[DJ194950]

One of those that may be a -ya buts-

Sounds more like 2 issues. Deal with the one your aware of first.

Suspect a fuel delivery problem also, more on that later if need be. We will see.

 

Hope it's come out an easy fix.

Hope the first takes care of the problem.

DJ

Edited September 14, 2014 by DJ194950

[Don Coatney]

When I first bought my car it had a half fast 12 volt conversion. I bought a new battery and the generator was not generating. I drove my car to work (10 mile round trip)daily for a couple weeks leaving in daylight hours and returning after dark. Every third day I would charge the battery. The engine never misfired.

 

[_shel_ny]

That may be, but I know that she should run with the battery unplugged, and should keep a charge, so Im gonna solve this problem, and then start on the next one. And I believe there was recently some discussion about the same problem I have, and the general consensus was that if the car was having to run off the battery's power, that at higher rpms, it would lose power and sputter and cut out like mine is- so maybe I'll kill several birds with one stone!

 

Are you getting into 4th gear yet? On a prior posting you were not shifting from 3rd due to the lack of required wiring to make the M-6 function properly.

 

Probably takes a good battery to run without a working generator. A marginal/poor battery may get you started after you charge it, but then not hold up for long to keep everything functional. Recharge, starts, but then same deal over again. It does sound like you have a generator problem, but the battery could contribute as well.  Even with a working generator, and a good battery it may be necessary to bump the throttle up a bit before pulling the battery cable off.

 

Have you done a generator motoring test to check for generator output?

Edited September 14, 2014 by shel_ny

[ledfootslim]

Are you getting into 4th gear yet? On a prior posting you were not shifting from 3rd due to the lack of required wiring to make the M-6 function properly.

 

Probably takes a good battery to run without a working generator. A marginal/poor battery may get you started after you charge it, but then not hold up for long to keep everything functional. Recharge, starts, but then same deal over again. It does sound like you have a generator problem, but the battery could contribute as well.  Even with a working generator, and a good battery it may be necessary to bump the throttle up a bit before pulling the battery cable off.

 

Have you done a generator motoring test to check for generator output?

I have not done that test, so thank you for providing it! I have a manual on the way, so that should help.

I do not know if I am getting to fourth gear, as she isn't driving well enough to really test her out.

And I have wondered about the battery- it is a industrial and farm one, one of the few I could find. What kinda batteries are you guys using? My grandad says that he had a golf cart battery in his '49 Ford p-up, and it would start everyday, freezing or summer.

          And I tried opening up the throttle pretty good and taking the lead off, and it dies within seconds regardless.

[_shel_ny]

I have not done that test, so thank you for providing it! I have a manual on the way, so that should help.

I do not know if I am getting to fourth gear, as she isn't driving well enough to really test her out.

And I have wondered about the battery- it is a industrial and farm one, one of the few I could find. What kinda batteries are you guys using? My grandad says that he had a golf cart battery in his '49 Ford p-up, and it would start everyday, freezing or summer.

          And I tried opening up the throttle pretty good and taking the lead off, and it dies within seconds regardless.

 

 

That motoring test should be helpful. I have used it with a generator that is not in a vehicle to see if it works before installing it. There is another test that is done with the vehicle running. I have not done that one. It also involves a jumper wire to determine if the VR may be at fault. I don't remember how that one is done. It has been posted before. Perhaps someone will chime in, or link the thread.

[_shel_ny]

I had the generator re-built professionally a few months ago, but I may take it back. As soon as I turn my key on, the ammeter drops below negative, and remains there,

 

Dropping (-) is normal when not running.

 

Has this been a issue since the gen. was rebuilt? Was this an issue before the gen. was rebuilt, as in why did you have the gen. rebuilt?

 

Has this generator been polarized?

 

Zen Masters/Gurus:

Does this generator need to be polarized ?? 

Edited September 14, 2014 by shel_ny

[Don Coatney]

[Dodgeb4ya]

"Correct me if I'm wrong (I'm 1000 miles from my cars), but isn't the big lug on the generator hot all the time? If you have nothing there it puts you pretty much on the problem."

There will be NO hot Voltage reading at either the small "Field" or the larger "Arm" terminals on the generator with the key off on a properly charging MoPar 6 volt generator..

Bob

[MBF]

Are the connections for the 3 wires on the VR clean, tight, and on the correct terminals?  Same for the posts on the generator.  You can check simple stuff first while you're waiting for the manual to arrive.  Just went through the charging issue with my 2.5 ton.  It ended up being a bad voltage regulator, but I did the testing and swapped in a known working used one that I had on the shelf.  Mike

[ledfootslim]

Ok, I did not do anything like this. First, is my genny a delco or ford/lincoln type? Should I wait for the manual for this info? And which one is the FLD terminal?

And I just had them rebuild the generator because the starter was worn out and I was already taking it in to them- and in the few times it was running before the re-build, the ancient battery it came with didn't stay charged either, now that I think of it. Though that may have been just the age and condition of the battery.

[ledfootslim]

Are the connections for the 3 wires on the VR clean, tight, and on the correct terminals?  Same for the posts on the generator.  You can check simple stuff first while you're waiting for the manual to arrive.  Just went through the charging issue with my 2.5 ton.  It ended up being a bad voltage regulator, but I did the testing and swapped in a known working used one that I had on the shelf.  Mike

I am not sure if the wires are on correctly at the VR, we just put them back where they were to begin with, replacing the nastier ones. I wasn't sure about taking the wires off while running to check if that made a difference- is that what you are suggesting?