Battery or Altenator?

[68Formula]

About a month ago, I drove my Pontiac and left the lights on. Jumped the car all was fine.

Drove the car yesterday. Stopped and restarted once with no problems. But it died at the gas station, and didn't have enough juice.

Went to jump it (it was dark by this time) both positive and negative are black and the routing is weird (long story). Before I started the jump vehicle, I momentarily swapped positive and negative. Corrected it, restarted the car and drove home.

Interior left blinker light stayed solid when signaling left, and nothing signaling right. Gages were completely dark. Wife followed and said the brake lights were fine, but the taillights were so dim she wasn't sure if they were on (they were). My headlights were also so dim (but on), I couldn't see much of anything (good thing I was only 1 mile from home and most of that was through our subdivision).

Put a voltage meter in the cig lighter, and after rejumping it in the driveway it read 12.5volts. After letting it run, it was up to 12.8volts. Disconnected the jump car, and voltage dropped to 11.8v. When I put on the headlights it dropped to 11.2v. Turning them off, it went back up to 11.8v again. Turn off car and won't restart.

Is this a battery or alternator problem, or both (did I fry the alt)? Battery is heavy duty (biggest one that would fit - figured I need it since the car is not driven daily), but probably about 7 years old now. Alternator was purchased new in 2004 when I went to single wire.

Also, if I have to replace the alternator, I'd like to get one with more output since the future calls for fuel injection, electric fans, and power seats. What would be a good replacement (you know how modern parts stores are - you have to ask by vehicle and engine size). Something from a luxury GM car that would have lots of bells and whistles like a Cadillac, Olds or Buick? I don't want to spend a ton of cash on a fancy chome model, or high output aftermarket one, if I can simply buy one for another model that puts out more and costs about the same as a replacement. Again, it would have to be a single wire one.

Thanks.

[Yoda4561]

Sounds like you've at least toasted the battery, probably before you even swapped the jumper cables. Alternator is also likely, probably the reason the battery died at the gas station was that the alternator wasn't charging properly. Take it down to sears or someplace and have them load check the electrical system, they usually do this for free or close to it, although they usually expect you to buy a new battery there if it turns out to be a problem.

Edit: The biggest problem with your setup is probably that single wire alternator. Go to a 3 wire setup, it charges MUCH better at idle and low speed.

[68Formula]

The biggest problem with your setup is probably that single wire alternator. Go to a 3 wire setup, it charges MUCH better at idle and low speed.

I'm assuming by 3 wire you mean the original setup? I believe everything is still in place. That should have an external regulator, correct? Are the external regulators as reliable?

[Yoda4561]

No, by that I mean a GM 12si 94 amp alternator(84 camaro G code 305, and a few others from the mid-80's), or a CS130 from a latemodel, both internally regulated. The 12si is supposed to be one of the most reliable alternators GM made, the cs130 has better output, but the wiring is a bit more complicated and the alternator isn't as "bulletproof". The wiring is pretty simple for the 12si, I doubt it would take anyone more than an hour to do correctly. Go to mad electrical's website and read up on their alternator stuff, I double checked with some other online sources and their info is pretty spot on. Since it's a pontiac there may be some differences in the warning light/resistor setup, so make sure to do some homework on the proper setup, and then you can grab a new alternator at any local parts store.


http://www.madelectrical.com/electricaltech/onewire-threewire.shtml
http://www.madelectrical.com/electricaltech/delcoremy.shtml
http://www.madelectrical.com/electricaltech/howitworks.shtml

Interestingly just going to a similar amp rating on the internally regulated 10si, vs the old 10dn external yeilds 4x the current at idle.

http://www.chevelles.com/forums/showthread.php?p=2745989 I also found this helpful, it kind of illustrates how simple the late model 3 wire is.

[BonzoHansen]

Will the battery hold a charge?


I posted this the other day.

I tripped on this the other day. This is a screen cap from a larger install document I found on the GMPP site. It is how GM Performance Parts says to wire the CS130 that comes with the serp setup they sell. IROC setup. They just jump the S term to the BAT stud. I ran that lead along with the BAT lead to a junction point. I ran the factory brown idiot light circuit to the L term.

https://static1.pt-content.com/images/pt/2010/02/th_CS130_Wiring_As_Per_GMPP-1.png (http://smg.photobucket.com/albums/v359/SIBLY/Cars/?action=view&current=CS130_Wiring_As_Per_GMPP.png)

My 77 had no external reg of course. If it did it would have hit the trash. :)

[H2Ogbodies]

Ahhhh...another 1-wire alternator toasted. Why anybody runs one is beyond me. They DO NOT have the ability to regulate voltage-so they put out a high amount of amperage at low speed-what this means is you literally bake your charging system through the wiring. Resistance builds heat, if you have say 40 amps @ idle from the alternator but the car is only consuming 30 amps worth of power, then your wiring and alternator itself is "absorbing" the extra amps through heat via higher resistance. Go back to a 3-wire setup-from the harness side of your external regulator, splice the blue and brown wires together and cap the orange and yellow ones off. Now, run an 8 ga. wire from the alt. charge post to your battery, go to a parts store and grab the HELP section three wire CS type alt. harness. The black wire is not used, cap it off. The white wire gets spliced with yoru OEM brown wire from the alt. harness and the larger red 10 gauge wire from your OEM alt. harness gets splcied to the large red lead on the new CS alt. harness. If youhave idot lights you are done. If you are runnign factory style Ammeter gauges, you need a diode-check madelectrical for the correct value-I can't remember what it should be.

[68Formula]

Go back to a 3-wire setup-from the harness side of your external regulator, splice the blue and brown wires together and cap the orange and yellow ones off. Now, run an 8 ga. wire from the alt. charge post to your battery, go to a parts store and grab the HELP section three wire CS type alt. harness. The black wire is not used, cap it off. The white wire gets spliced with yoru OEM brown wire from the alt. harness and the larger red 10 gauge wire from your OEM alt. harness gets splcied to the large red lead on the new CS alt. harness. If youhave idot lights you are done. If you are runnign factory style Ammeter gauges, you need a diode-check madelectrical for the correct value-I can't remember what it should be.

This post is awesome! I think even an electrically challenged person like me can handle this.

So judging from the fact this would use a CS alt. harness, this is how I would wire a CS130? Or am I just using a CS harness to adapt a 12si?

P.S. I yanked the negative terminal on the battery and it kills the engine. Plus my multimeter shows nothing off the alternator when it's running.

[chevyhector]

Thanks guys! I've learned a new thing today!

[kryptik]

This post is awesome! I think even an electrically challenged person like me can handle this.

So judging from the fact this would use a CS alt. harness, I'll want to get a CS130 alternator rather than a 12si?

P.S. I yanked the negative terminal on the battery and it kills the engine. Plus my multimeter shows nothing off the alternator when it's running.

Yes if disconnecting the battery kills the ignition, then your alternator is not properly charging. You should also have output on the meter when the alternator is spinning.

I would definitely recommend a CS alternator over a 12si, considering it is just as easy to bolt in. If you do the conversion to a 12si, you can do the conversion to a CS with almost nothing extra, short of a different mounting bolt and a harness adapter.

[BonzoHansen]

P.S. I yanked the negative terminal on the battery and it kills the engine. Plus my multimeter shows nothing off the alternator when it's running.that can damage an alternator as well.

[H2Ogbodies]

You can run either style alternator but-I would run a CS style-it'll fit, even a 6" case one. Both alt. style take the same pigtail harness....now, 95, 96-up GM cars have a different connector that to my knowledge nobody makes a pigtail for so it's a boneyard item-usually you can't use these due to the bolt pattern clocking. I use alts from 90's 3.8 Buick motor equipped cars, Pontiac Trans Port vans, Caprices, S-10's...there's actually quite a few you could choose from. All of these can be used on your accessory drive you have now. Options are slightly less if you plan to run a serpentine but again, you still have a lot of options. 1-wire alts are never worth the money in the long run.

[TnBlkC230WZ]

Ahhhh...another 1-wire alternator toasted. Why anybody runs one is beyond me. They DO NOT have the ability to regulate voltage-so they put out a high amount of amperage at low speed-what this means is you literally bake your charging system through the wiring. Resistance builds heat, if you have say 40 amps @ idle from the alternator but the car is only consuming 30 amps worth of power, then your wiring and alternator itself is "absorbing" the extra amps through heat via higher resistance. Go back to a 3-wire setup-from the harness side of your external regulator, splice the blue and brown wires together and cap the orange and yellow ones off. Now, run an 8 ga. wire from the alt. charge post to your battery, go to a parts store and grab the HELP section three wire CS type alt. harness. The black wire is not used, cap it off. The white wire gets spliced with yoru OEM brown wire from the alt. harness and the larger red 10 gauge wire from your OEM alt. harness gets splcied to the large red lead on the new CS alt. harness. If youhave idot lights you are done. If you are runnign factory style Ammeter gauges, you need a diode-check madelectrical for the correct value-I can't remember what it should be.

This is so true. The CS altenators are the best wayto go. It is very easy to wire in a CS altenator. You only have two more wires and possibly resistor you don't use your factory idiot light.