Alternator/regulator question

[DirtDog]

OK for those that don't know I have an 06 GP GXP with the 5.3L LS4. Now lately I've been having a problem with the voltage in the system fluctuating from 15.2 (which used to be around where the normal was for my car before this problem) to 12.5 is as low as I've seen it go. I have had the battery tested as well and every time it turns out fine.

So my question is could the regulator in the alternator be going bad? Even though it is computer controlled. When the bower goes down to under 13 it comes up on the DIC and says power saver mode activated!

Before I went to Cali 3 months ago I would start the car and it would start off at the normal it always had then over about a minute it should slowly go down to 13 then when I came back (it set without getting started for 6 weeks) it started just fluctuating like it is now

Opinions ideas. And yes Saturday we disconnected all the connections and made sure they were spotless and clean

[oldgtpowner01]

I know some fluctuation is normal since it is computer controlled. Sometimes those things will test good as will batteries but there still may be a problem. How old is your battery? If it is more than 4 years old I would replace that with a high quality part first and see what happens. We do replace alternators on those cars every so often in the 100k range. Another thing i see sometimes are corroded battery terminals, if they are bad enough that may cause an issue charging as well. Sounds like you have addressed that though. Chevrolet service consultant/ tech here. Typically if a regulator fails it would not stay within the parameters that you are seeing.

chris

[DirtDog]

I know some fluctuation is normal since it is computer controlled. Sometimes those things will test good as will batteries but there still may be a problem. How old is your battery? If it is more than 4 years old I would replace that with a high quality part first and see what happens. We do replace alternators on those cars every so often in the 100k range. Another thing i see sometimes are corroded battery terminals, if they are bad enough that may cause an issue charging as well. Sounds like you have addressed that though. Chevrolet service consultant/ tech here.

chris

Well I did have corrosion on the battery and I cleaned it all off and still had the fluctuating voltage...the car used to stay steady around 15volts but now its going so low as to trip the power saver mode on. The alternator has been replaced before (not by me though) and the way I can tell is the stock brand is delco and it has a Remy on it now.

I'll go out and check my battery date ghats stamped on battery

[91parkave]

Go have a Alt/batt load test done at Autozone it is possible Your battery Is on its way out but that's usually only for starting AS however if its bad enough it will drag The alternator down with it. Regardless just have the system tested and go from there

[DirtDog]

Yea I had them test it along with two other stores and the battery and alternator shows its fine. But lately I've been getting a lot of corrosion build up. I sprayed some anti corrosion on it Saturday after I clean it but I still have the problem.

[jteske88]

Man, i know i get some fluctaition but 12.8 is the lowest mine has ever gone, no battery mode saver message. If you battery is dipping below the 12.5 that is def on just bat at that point and would lead me to believe something with the alt. And im charging not just one batt but three. NO issues. If the load test doesnt show the issue maybe your alt sensewire is f'd up and throwing off the reading. Did you mess with the clamp near the batt at all? Run any wire Through it?

[DirtDog]

Man, i know i get some fluctaition but 12.8 is the lowest mine has ever gone, no battery mode saver message. If you battery is dipping below the 12.5 that is def on just bat at that point and would lead me to believe something with the alt. And im charging not just one batt but three. NO issues. If the load test doesnt show the issue maybe your alt sensewire is f'd up and throwing off the reading. Did you mess with the clamp near the batt at all? Run any wire Through it?

The positive wire that's on the alt...I took it off and made sure it was spotless...and the wires from the wire harness I took off and also made sure the connectors were good. Which salt sensewire are u referring to?

On the battery I took both the positive and negative off and used a wire brush on em to make sure they were nice and clean. I put some anti corrosion stuff on them as well so the connections are good

[jteske88]

the sense wire is one of the wires in the harness that goes to the Alt to tell it to turn out or what voltage to output. You say you replaced the connections? I did the same and i thought it was fine untill it started acting funny. Had to redo it but i also added better ground wire to frame/engine. Could be a bad ground somewhere also. Kinda alot of options to go through.
Or your BCM dont like you

[DirtDog]

the sense wire is one of the wires in the harness that goes to the Alt to tell it to turn out or what voltage to output. You say you replaced the connections? I did the same and i thought it was fine untill it started acting funny. Had to redo it but i also added better ground wire to frame/engine. Could be a bad ground somewhere also. Kinda alot of options to go through.
Or your BCM dont like you

Yea...I'll go through all the connection more thoroughly today when my new fogs come in...and let's just not bring the bcm into this discussion just yet...

[DirtDog]

O and it runs fine when I start her for the first time or when she's been sitting awhile...normal voltage and everything then after the engine gets good and warm the voltage just drops

[jteske88]

you just watch it on the dic? but this is like my abs issue and being a wire. hot no likey, cold it love it. Im not ruling that its the wire. but i dont know what else it could be if all is checking out.

[DirtDog]

I'm hoping its just a bad battery cause infused to never get corrosion on my battery then it all of a sudden appeared on the batter. I cleaned it off once...then literally a week later it was back. So this time I cleaned it and sprayed anti corrosion stuff on it. And yea I watch it on the DIC but its never fluctuated like this bad before

[jteske88]

yeah batt could be way out

[DirtDog]

I guess I'll replace the battery and hope that fixed the problem. I'm also doing the big three upgrade as well so I'll do em at the same time

[91parkave]

Did you ever go get the charging system tested out? I'd try to nail electrical gremlins out before you upgrade , could be more of a headache if the problem persist

[DirtDog]

Yea I had it tested and they said battery and alt were fine but I know some things up. I'm gonna get a new battery next paycheck

[91parkave]

There's a Little clamp that goes around the negative cable is it connected ?

[DirtDog]

There's a Little clamp that goes around the negative cable is it connected ?

I wanna say yes. Could u provide a pic as to what ur referring to? And I'll go look

[jteske88]

That the hoop that the negative runs thorugh by the battery,

[DirtDog]

I'm gonna go check it out...what's that hoop do?