Pulsating Power Supply and Electronics

[Christopherrr]

I think my alternator is going south...

In recent weeks I've noticed that my voltage guage has been flucuating up and down...nothing big, I just figured it was normal...okay not really. Last week I noticed that the voltage has been ranging from 15 volts to 16 volts (noramally it would be in the 13-14 volt range), indicating an overcharge and the fluctating increased; so much that I you can see lights and electronics pulsate that correspond with the fluctuating voltage.

Is this confirmation that the alternator is on its last leg? Or could it be something else? All connections are clean and rust/corrosion free. Grounds have good connections too. I just want insight before I head out for new parts...ie alternator, battery. Yay.

How bout it cowboys?

[Trans Am]

dont know about cowboys, but the voltage regulator might be going south. cowboys seem to be going to clearwater , florida lately and they tend to buy mustangs. dont know about their regulators thogh, dont even want to know . i think its part of the alternator and maybe you can replace only that instead of the whole alternator.

[Christopherrr]

Well, I did a test on my alternator...unplugged my battery and turn on all electronics. It kept everything running perfectly...but I still had that annoying dimming/brightening thingy. It's late...I can't think of a word to describe it.

Where's the regulator at?

[Jeff_in_Atl]

Well my Mustang did the same thing. It was caused by the stereo sub amp not pulling a steady current. The kick drum would hit and make the amp want power. The regulator would sense it and tell the alternator to give me all you got. The brushes rubbing the armature would spark so hard they would leave a black mark and a small divot like a welder. After a while the entire armature would be black with tiny little divots and it would quit working. When it was partially scored it would pulsate the electronics just like you are describing. I would take it apart and lightly sand the commentator to remove the scoring. Put it back together and the lights would be steady again. I finally figured out that if I put a big capacitor on the sub amp it would stop burring the commentator and it did.

I'd say it's in the alternator not the regulator. The alternator is mounted in the back side of the alternator. If you felt adventurous you could take it apart and see if the armature is scored. If you don't feel like fooling with it you could just replace the alternator. Usually a regulator comes with it.

[Joe 1320]

You may have a loose positive terminal in the alternator. The single positive post can sometimes work loose, causing fluctuations in the current draw. While the cable may actually be tight against the post, you should not be able to wiggle the post or twist it an any fashion, it should remain tight. It may also be worth it to pull the alternator and have it tested for free at your local auto parts store just in case.

[Christopherrr]

Well my Mustang did the same thing. It was caused by the stereo sub amp not pulling a steady current. The kick drum would hit and make the amp want power. The regulator would sense it and tell the alternator to give me all you got. The brushes rubbing the armature would spark so hard they would leave a black mark and a small divot like a welder. After a while the entire armature would be black with tiny little divots and it would quit working. When it was partially scored it would pulsate the electronics just like you are describing. I would take it apart and lightly sand the commentator to remove the scoring. Put it back together and the lights would be steady again. I finally figured out that if I put a big capacitor on the sub amp it would stop burring the commentator and it did.

I'd say it's in the alternator not the regulator. The alternator is mounted in the back side of the alternator. If you felt adventurous you could take it apart and see if the armature is scored. If you don't feel like fooling with it you could just replace the alternator. Usually a regulator comes with it.

I thought it would my sub too, but I unplugged my basslink and it still did it.

You may have a loose positive terminal in the alternator. The single positive post can sometimes work loose, causing fluctuations in the current draw. While the cable may actually be tight against the post, you should not be able to wiggle the post or twist it an any fashion, it should remain tight. It may also be worth it to pull the alternator and have it tested for free at your local auto parts store just in case.

Yeah, I'll jjust dish out the $$$ for a new one. I figure I should...it's been 220K on the factory unit.

Thank guys.

[Z Ya Later]

If I may make a suggestion, if you've got the money and want a brand new unit and not a reman., give Powermaster a call. They sell their alternators in a couple different finishes and several different amp ratings. I've been really happy with my 140 amp chrome unit.

[Jeff_in_Atl]

I thought it would my sub too, but I unplugged my basslink and it still did it.

Unplugging it won't do any good. The damage is already done (if that is what is wrong). If you do have an aftermarket sub amp you really should have a cap on it.

Yeah, I'll just dish out the $$$ for a new one. I figure I should...it's been 220K on the factory unit.

Thank guys.

Did you exchange your old one? If not, take it apart and see if the armature is burnt.

[Christopherrr]

Will do Jeff...thanks guys.

[fastTa]

Voltage regulators are almost always the cause of the "flickering" interior lights and electronics.

You should be able to find a local alternator shop to rebuild your alternator. It normally runs about $65-$85, and will normally be of better quality than a new one.

[Christopherrr]

Thanks Joe for the advice...it worked. Clean and tighten the connections and everything is back to normal. Yay!

[Joe 1320]

Thanks Joe for the advice...it worked. Clean and tighten the connections and everything is back to normal. Yay!

Glad it worked. Gotta love the cheap fixes.

[fastTa]

The best fixes are the free ones!

[Christopherrr]

Glad it worked. Gotta love the cheap fixes.

yes I do...

The best fixes are the free ones!

indeed!