Alternator Going?

I bought a 110 amp alternator from AutoZone last year to replace the factory alternator that went out and haven't had any issues until this winter. Sometimes (usually in the morning when it's really cold) the voltmeter will only show that I'm at 12V (sometimes less) when I'm idling (after the engine is warm). Then when I start driving the volts go up as the RPM's go up. Other mornings, the volt gauge says 14V+ and the alt seems to be putting out a ton.

I do have a stereo system with subs, 1.6 farad capacitor, etc, and sometimes the volts output seems affected by having the stereo on and sometimes it seems completely unaffected.

This issue has caused me to have to jump the car sometimes (the battery acts as if it's dead), but what's strange is that sometimes it starts right up without hesitating.

It seems like the alternator is on it's way out, but could anything else be causing this? The last time I had to replace the alternator, it would just never go above 12V as if I didn't even have an alternator. This is a little weirder. Could I have a weak alternator bearing or something?
I still have the same duralast gold battery that was in the car when I purchased it so at minimum the battery is 5 years old. Could a floating short in the battery be causing this?

Thanks for any help....

I've had good luck with AZ Duralast batteries but best to take it to the Zone and get it tested. However, bad luck with AZ rebuilt/reman parts. The voltage fluctuation and change due to load is normally a flaky voltage regulator in the alternator.

You sure a 110 amp alternator is good enough considering your sound system? :grinno:

I've had good luck with AZ Duralast batteries but best to take it to the Zone and get it tested. However, bad luck with AZ rebuilt/reman parts. The voltage fluctuation and change due to load is normally a flaky voltage regulator in the alternator.

You sure a 110 amp alternator is good enough considering your sound system? :grinno:

Hey Bob. Yeah, you're probably right. The problem is that I need to take the car to AZ and have them test the alternator when it's acting up otherwise I don't think they'll warranty it if it tests out during one of it's behaving times (at least if they're anything like Checker was when I worked there).

No, I would much rather have a higher output alt, but I have no clue where to find them! O'reilley's seem to top out at 110 amps too! :dunno: I haven't had great luck with Napa parts so usually avoid them. What do you recommend?

I bought a 110 amp alternator from AutoZone last year to replace the factory alternator that went out and haven't had any issues until this winter. Sometimes (usually in the morning when it's really cold) the voltmeter will only show that I'm at 12V (sometimes less) when I'm idling (after the engine is warm). Then when I start driving the volts go up as the RPM's go up. Other mornings, the volt gauge says 14V+ and the alt seems to be putting out a ton.

I do have a stereo system with subs, 1.6 farad capacitor, etc, and sometimes the volts output seems affected by having the stereo on and sometimes it seems completely unaffected.

This issue has caused me to have to jump the car sometimes (the battery acts as if it's dead), but what's strange is that sometimes it starts right up without hesitating.

It seems like the alternator is on it's way out, but could anything else be causing this? The last time I had to replace the alternator, it would just never go above 12V as if I didn't even have an alternator. This is a little weirder. Could I have a weak alternator bearing or something?
I still have the same duralast gold battery that was in the car when I purchased it so at minimum the battery is 5 years old. Could a floating short in the battery be causing this?

Thanks for any help....

i got a 83 buick that's over chargeing and it's the battery that's bad not good on the alt. and like he sais duralast is best battery i've bought and still will buy duralast if battery go's bad.

No, I would much rather have a higher output alt, but I have no clue where to find them! What do you recommend?

The HO alternator. We have some old discussions and sources, mostly on-line. I'll see if I can find some.

Yeah, I just checked Napa just for kicks and they didn't have anything higher than 110 amps either.

So do you think I should just eat the warranty on the AZ alternator and start fresh with an HO one?

Hey Matt,

Bring it to AZ for testing, if its bad get a replacement under warrenty for the time being. Then look for higher output ones. Are you sure your system is turning off properly when you shut the car off?

Otherwise, I know the PCM wont command the alternator the charge until a few seconds after the car has started. Sort of a failsafe to keep the alternator from going full field right away and burning up the regulator.

I'd take the batt and alternator in for testing.

By system, do you mean stereo system? If so, then yes, I know everything shuts off when the car does.

If not, then I'm not sure. Everything looks shut off when I leave the car.... :D

Would an alternator from a '98 Bonnie SSEI be a direct swap?

Yes, system I meant sterio system

And no, 98 and previous years are different. Brackets bold up different. It will not work.

You need 99+

K, so a 99+ and I'm good....

I didn't get to an AZ today, but I'll try very soon.

Well, I tore out the alternator and took it to AZ to have it tested and everything tested out well. I was afraid that would happen, because the alt does behave half the time. I also checked out the Bonnie alt's and they seem to be completely different in terms of mounting design, so that was out (the alt for the '98 was the same for the '99). So as a hail mary I put in a new battery and new battery cable bolts and that didn't change anything.

So. Anyone have any ideas? Any idea as to where to get an HO alternator for these cars?


EDIT:

For my info, here is one JC Whitney has for pretty cheap. 200 amps.

http://www.jcwhitney.com/bosch-alternators/p2018615.jcwx?filterid=c1579d1833y2000f6j1

Any idea as to where to get an HO alternator for these cars?

Suppliers on EBay or Amazon.com have them. 220 amp. See link below for an example.

Click here (http://www.amazon.com/GRAND-PRIX-3-8L-OUTPUT-ALTERNATOR/dp/B003D7XSFG/ref=pd_sbs_auto_1)

Since the battery is 5 years old, and it seems to act up only when it's extremely cold out, I would suspect the battery is on it's last legs. It's 5 years old, and you have a bunch of add-on stereo equipment that adds additional strain on the electrical system. Since the volt guage in the car reads system voltage, when the battery is extremely cold, the dash guage will read lower until the battery is warmed up a bit and will accept a charge. I would double check alternator output with a volt meter rather than trusting the in-dash guage.

Hey Rich. Yeah, I got a new battery and that didn't change anything. It's weird - it's like I only have the low voltage reading when I'm idling. Once the car starts going, then the volts go up with the RPM's. My first notion is to now just get an HO alternator, but I'm not sure if that will fix it. It seems like the current alternator just isn't spinning fast enough when idling. Wouldn't an HO alternator potentially have the same problem? Or does an HO alternator put out more electricty per pulley revolution?

Typically, alternators only put out about 60-70% of rated amperage at rpm's below 1000 or so. A heavier duty alternator may or may not help your issue at idle, especially with the add-on stereo. Since you have a quite large capacitor installed, I assume this is a pretty big watt system.

Eh, it's decent sized I guess. It's a 3000w amp, but I think it's only like 500 watts RMS so not crazy. The deck is a Sony 52Wx4. What's weird is that I've had this system since about April-ish and haven't had any issues until recently. What I don't get is that in the morning sometimes I won't even turn the stereo on at all and I still have the same problems. Yeah, I've noticed that the stereo can make it worse, but it still happens either way. :(

Typically H.O. alternators put out around 105 amps at idle which is much better than OE/stock. For example a 220 amp H.O. alternator will achieve full output at around 1200 rpm.

Another factor is the rating of the battery and reserve capacity. Thats why most people with decent aftermarket high power stereo systems not only install a H.O. alternator but a better battery like the Optima Red or Yellow tops.

Regardless wiring from the output from the alternator should be upgraded to 4 gauge main charging wiring for maximum current flow to the battery.

Based on your symptoms you could have a combination of issues. If you are going to dump a bunch of money into a system then it doesn't hurt to upgrade the basic charging system if it is stock.

Cool, thanks Bob.

Hmmm.... Maybe I'll try that Bosch HO alternator then. $120, 200 amp, and 1 yr warranty on it.

How difficult of a job is it to upgrade the wiring? I've never done that before on any vehicle. Do you just take a 4 gauge wire and run it straight from the alt to the battery or do you have to change out harnesses and spaghetti bowls of wiring?

No comment on Bosch stuff. :grinno:

Rich probably will. :lol:

You can get H.O. alternator wiring kits ready to go from on-line stores or at auto parts stores or make your own. The wire is the alternator output wire going back to the battery positive cable/terminal. Keep in mind this should be fused. Up to 250 amp fuse. The stock setup has a fusible link.

Here's an example (instructions) from a rather pricey kit. 0 gauge kit with a 250 amp fuse.

Click here (http://www.powerbastards.com/Instructions/0_Gauge_Wiring_Instructions.pdf)

No comment on Bosch stuff. :grinno:

Rich probably will. :lol:


Crap! You had to rain on my parade!! :p

You can get H.O. alternator wiring kits ready to go from on-line stores or at auto parts stores or make your own. The wire is the alternator output wire going back to the battery positive cable/terminal. Keep in mind this should be fused. Up to 250 amp fuse. The stock setup has a fusible link.


Awesome, thank you! It looks like they do just "add" a BFW to the existing wiring which is easy peasy! I was really hoping that was the case!

I've measured the output at the battery, but never at the alternator. I probably should at some point.

never tried a Bosch Alternator...that is all I will say!

never tried a Bosch Alternator...that is all I will say!

:lol:

Probably for a good reason. Can't complain about the price though. But I'd pass. Had to replace the stock Bosch alternator in my Audi 100LS back in the late 70s.

My brother said he used to have a Bosch alternator and he loved it. He said even after a head gasket blew and drenched it in oil, it never failed.

In talking to the same brother (who worked at AZ) he confirmed that the AZ remans are garbage. He said he went through 3 or 4 in the space of a year and finally but in a new AZ alternator and hasn't had problems since. If I went that route, I'd only be out $25, but the old alternator has to test bad first. The more I watch the alt behavior, the more I'm thinking it is the regulator. There are times that I can be idling at a light with the defroster blasting, the lights on, the stereo thumping, and it doesn't flinch while staying strong at 14V. Other times nothing will be one but the blinker and that will cause voltage drops.

So I still haven't made a move yet. I'm kind of hoping it will just die like the factory one did.

I could help you get the factory one to die.... :P

Matt, did you get my PM response about the LCA arms? My wifi was acting up so I'm not sure it went through.

I could help you get the factory one to die.... :P

Yeah, that's the same thing my bro told me. :p

Matt, did you get my PM response about the LCA arms? My wifi was acting up so I'm not sure it went through.

I sure did! Thanks! :biggrin: