Is this signs of a bad alternator? (Videos)

[vxvxAndrewxvxv]

Here are some video's of what I'm observing.
Car has a nippendenso Alternator on it, 85 L-body.


First video is of the in dash dash gauge

http://www.youtube.com/watch?v=NVfk5FjNt_0


Second is an amp meter around the power lead from alternator.

http://www.youtube.com/watch?v=Jii8YqJJ3f0


Third and fourth is volt meter at battery

http://www.youtube.com/watch?v=903j1EmbR6Q


http://www.youtube.com/watch?v=RIl4ou4BxSM

[vxvxAndrewxvxv]

Forgot to add, is does it only at 3000 rpm and higher.

[JDAWG]

how many amps did it say?

[vxvxAndrewxvxv]

peak was 50. the car headlights were on but other than that I believe no draw. the battery has been relocated to the back with a FWDP kit.

[JDAWG]

are you having a problem? the clamp meter is only going to read what draw you put on it, so you were drawing about 50 amps, turn other stuff on and see what it does

[vxvxAndrewxvxv]

the only problem i notice is the flickering battery gauge and the lights flicker a bit

[iTurbo]

Looks VERY similar to the failed alternator I had in my '86 GLH Turbo. The volt meter would freak out like that and it got so bad my stereo would shut on/off almost constantly. I had already put a 90 amp ND alternator in my car so I took it back out and found the brushes were worn down to almost nothing and the springs were fully extended. I thought I could get new brushes but the shaft had deep grooves worn into it.

I would remove the alternator and have it bench tested at NAPA or just pull the brushes out yourself and post a pic of them.

[shackwrrr]

looks like the "sense" wire for the alternator has resistance somewhere

[turbovanman²]

Are you running an underdrive pulley? I would pay a shop a few bucks to test it properly, ;)

[vxvxAndrewxvxv]

Are you running an underdrive pulley? I would pay a shop a few bucks to test it properly,

No UDP. I don't know of any shops in the area. yellow pages here I come.

[bakes]

Looks more like the brushes are worn out too me. Take the alt to napa or pep boys and have them test it on there bench tester they do it for free.

[vxvxAndrewxvxv]

what pisses me off is it is less than 2 years old. It has less than 15 thousand miles on it.

[t3rse]

Any chain store can test it for you. Check the voltage on the switched field wire and make sure there isn't resistance as shackwrr stated.

[vxvxAndrewxvxv]

did not find any issues with the lead wires, Next step is to take it to a shop on monday for an inspection and test.

[vxvxAndrewxvxv]

Had the alternator bench tested today at a starter/alternator shop, it passed on all aspects. The tech then disassembled it and inspected the internals. He found nothing wrong. So I'm putting on all new terminals and adding new grounds. Didn't have time to finish it all tonight, so I will see soon I hope.

[vxvxAndrewxvxv]

Re installed everything and put all new terminals on the the harness. The car runs like crap now. It is missing and stumbling on its own face. Now it barely idles, and the voltage spiking is still present. Looks like this isn't going to be something that wants to be fixed.

[1984rampage]

Check the connections at the logic module.. My car wouldnt charge and it turned out I had a few corroded pins that were causing me trouble

[strang3majik]

alternators usually aren't spinning fast enough to actually charge until about 3000rpm. Thats why its making more volts there.
As far as the needle...I'd check the gauge out, or where it reads from.

[vxvxAndrewxvxv]

Check the connections at the logic module.. My car wouldnt charge and it turned out I had a few corroded pins that were causing me trouble

The alternator charges fine, as far as I can tell it isn't fluctuating. I will check the logic module connections.


alternators usually aren't spinning fast enough to actually charge until about 3000rpm. Thats why its making more volts there.
As far as the needle...I'd check the gauge out, or where it reads from.
I know the power is going crazy, the lights flicker like mad when the needle does.

Tomorrow I'm going to try swapping out the coil with another spare. I had suspected something with it last fall, and now I'm thinking what if it were shorting out? that would probably cause a fluctuation of some sort.

[strang3majik]

I'm just saying...I've seen gauges go bad and it cause stupid things like that...lol Not on a TD, but, on an older Dodge.

My dads 68 Charger, brand new everything electrical, bigger, higher amp alternator. Everytime he went to an idle, the lights would nearly go out and the amp guage would go to discharge. The cam isn't even that big, and, the battery should be able to keep them brighter than that.

Well, after replacing/upgrading everything along the electrical circuits...we decided to change out the gauge with another one.

Car is now always charging and the headlights no longer go dim at idle.

So...I still say just try swapping it out once. Not saying it'll fix the issue, but, it is potentially the problem.

[89ShelbyGuy]

Does this alt. have a internal voltage regulator or is it external? If its external, you might have a bad regulator??

Tom S

[vxvxAndrewxvxv]

Here is the latest update.

Problem is still around. I have replaced these items. Coil, Wires, Plugs, all terminals from battery to ground and battery to alternator.

I figured the alternator wasn't completely eliminated as a culprit, so I unhooked the power lead to it and ran the car to check if it was still there. The gauge sat a lot lower obviously but still flickered when brought up in the RPM's. The lights flicker like mad along with the gauge.

I think my next step is trying out different computers.

[zin]

Well, after replacing/upgrading everything along the electrical circuits...we decided to change out the gauge with another one.

Car is now always charging and the headlights no longer go dim at idle.

So...I still say just try swapping it out once. Not saying it'll fix the issue, but, it is potentially the problem.

I'll add an asterisk to this, in that you were dealing with an AMP meter, and one that puts all the current the car makes through it at that, so if it goes bad, all kinds of wackiness can ensue, including burning the car down to the ground!

That's why we don't have amp meters anymore, too dangerous, unless they are inductive...

Now for my more relevant .02 worth. I lean towards the brushes and/or a problem with the switched field wire, which would most likely be related to the power module...

Best of luck!!

Mike

[vxvxAndrewxvxv]

I'll add an asterisk to this, in that you were dealing with an AMP meter, and one that puts all the current the car makes through it at that, so if it goes bad, all kinds of wackiness can ensue, including burning the car down to the ground!

That's why we don't have amp meters anymore, too dangerous, unless they are inductive...

Now for my more relevant .02 worth. I lean towards the brushes and/or a problem with the switched field wire, which would most likely be related to the power module...

Best of luck!!

Mike
Using an inductive AMP clamp attached to my digital volt ohm meter. The brushes checked out fine when the alternator was torn down for inspection.

My next step was swapping out power modules. But i have to wait a little while until i can borrow a spare from a friend.