At wit's end - Alternator
 

I'm sure someone out there has been through this...

Battery is not getting recharged. Measure the output at the Battery - 12v. Measure at alternator 12v.

Replace alternator with nice new Bo$ch (ouch) - same problem.
Replace battery (100 bucks) - same problem

Check all grounds. File down leads to ensure good connections - same problem.

Check all fuses, connections, etc..

GOOD PART*** I unplug the + at the battery, Immediatly the alternator outputs 14.4 volts. Reconnect battery, drops back to 12 volts.

QUESTION@@ Is there a relay or diode or something that switches the path / current? Possible amperage leak?

With great pain, I must beg for advice...

Other note - When running off alternator (at 14.4v) the car will stall when I turn the headlights on...

Re: At wit's end - Alternator
 

I appreciate that you've checked your grounds but ... I had exactly the same symptoms and, despite having cleaned the grounds twixt firewall and brown earth rings I still suffered charging problems and rough idling. Have you tried connecting a booster cable to the brown lead earths and the other end directly to the neg of the battery. In my case this fixed everything and I chose to bypass the firewall earth mount using an earth braid (bolted to the existing stud) and an alternative cleaned hole in the firewall. Worth trying.

Thanks for replying.. I can try this.

I just want to drive this freakin' car... I have no problem fixing this and that as needed, this alternator issue is just so agravating.

You bypassed only the firewall ground? Cause there are like 12,000 grounds on this car. Could they have used cheaper wire in this car?

Thanks again, I will try this today. And if ANYONE is interested, I have a good working (now extra) 90 amp alternator. Let it go cheap...

-Jason

Not only do you have to clean the ground wires but you also have to clean and/or replace the treminals at the battery. Especially the posititive terminal where the 10 gauge (or so) wires connect. One is the wire from the alternator to charge the battery.

Could be even worse if the positive terminal has been replaced with one of the clamp on the cable styles.

Cleaning the connecting points in some instances is not enough. As mentioned, you may need to replace or augment the ground wire. Older cables develope internal corrosion, thus, high resistance to current flow.

Go ahead and check/replace cables as noted. But it sounds like you might have a monster amp draw somewhere. Could be a bad battery, minor short in battery cables that hasn't started on fire yet, something.

Your car should have come with the 115 amp alternator, not the 90 amp one. In any event, the voltage will start dropping like a rock once amp draw gets over about 45 amps. So I would get the draw tested. You should be able to get this done at a battery shop for cheap to free.

If I do have a monster draw somewhere (which I suspect as well) wouldn't one of the 60 fuses blow? Or should that indicate that the problem exists BEFORE the fusebox? Should I measure the amperage output at each fuse location? How can I test for resistance in each of the main grounds?

There has to be a logical order to follow...

There is no fusing between the alternator to starter, starter to battery and then battery to fuse/relay box. That is a long way and why I put fuses in the battery cables I build.

Now where your problem is will take some work. You could have heavy loads on the fused side of the fuse/relay box that are not enough to blow the fuses but big enough to knock down the battery and alternator. So I would first put an ammeter on the various cables going to the positive post on the battery terminal to get a clue if juice is going somewhere in a big fashion. And you probably have a big flow so need to use professional high level equipment because most multimeters won't take a measurement over 10 or 20 amps without blowing their fuses.

RIDDLE ME THIS.....

I just put the old alternator back in for kicks, and it works! 13.8v at the battery... WTF??

What gets me is that I had both of the alternators tested with a 40 amp load and they both were fine. Now the old one will supply the current I need. Maybe the internal regulator is cooked in the new one?

The other possibility is there were a couple of "iffy" grounds. I replaced a couple and filed down all the rest. Maybe there was an issue there as well.

Oh well. I'm not 100% confident that all is resolved, but will hope and pray that it continues to work. Now to replace those inner tie-rods.

Thanks to all who helped, I appreciate the input.

-Jason

i just went to this dance and you didn't say if your alternator lite comes when the key's on.

my alt lite was out with the key on and running voltage was 12.7.

replaced the bulb and lite is now on when the key's on, car not running, and 13.7v when idling.

i had this happen in a volvo some years back and the alt lite must be in 12v series, like old style xmas lites.

Yes, the infamous battery/alternator light... I believe that it is the light that is directly under the volt meter, opposite the oil light?
http://forums.pelicanparts.com/uploa...1068430605.jpg

If so, it does come on properly when being started or in the accessory mode, then it shuts off properly once the engine is started. I verified this by unplugging the D+ on the alternator. I will say the light is "slightly" more dull than the oil light, enough to notice, but clearly visible.

Oh yeah, here is the beast..
 

Oh yeah, here is the beast..
http://forums.pelicanparts.com/uploa...1068431614.jpg

mine is opposite the oil pressure lite but it's older and i don't know where you alt lite lives.

it was one thing to check.

Hell, my alt. light dosnt come on when I turn the key on....hmm, should I check it?
I think its charging,but my battery will go dead pretty fast if the car isnt running,and after I start it I have to rev it to 3k rpm before it will start charging.

I had the same problem, replaced the negative battery cable and solved the problem.

Your definately drawing current that you shouldn't be. Did you recently put in a new stereo? Check your main ground off of the battery and the one to the engine block. Other than that, check your fuses.

What is the voltage at the battery when the car is running?

Voltage regulator? Cheap, try it...

can this cause a problem? i have a crappy sony that the PO installed. seems very mickey mouse and ive had intermittent starting problems for some time

the car looks awesome by the way. makes me wish i had some nice new paint.

maybe your battery has turned to crap.internal short or something??

That paint is far from new. Took me 2 days of serious buffing to get it that far. Digital camera is so deceiving.

Check your wiring. Get your battery tested at a local shop.