3rd Gen Low Voltage Problem

[TheOGConCon]

Hey guys, it's been a long time since I've posted anything, so before I jump into the issue I'm having, a bit of an update is in order.

As far as electronics go, I've done a 55w projector retrofit, running two sets of House Tuning 30w pods, Smittybilt XRC 9.5, a CB, led lights on all corners, along with the primary interior lights, and I'm running all aftermarket audio (double din, touch screen, speakers powered off head unit, 10" sub powered by JBL GTO751EZ, roughly 500w RMS if I remember correctly)

Last winter I had an issue where the main ground in the fuse box fried itself, and had to have the dealership run all new wiring and replace the fuse box (don't recommend it, that was an expensive venture and if they hadn't underquoted me in the first place, I probably wouldn't be driving this truck anymore).

Now for the problem - I monitor engine diagnostics with the BAFX OBDII reader via Torque Pro, and yes I am aware that all of the readings need to be taken with a grain of salt. I've done comparisons between taking a multimeter reading while looking at my voltage on Torque, and it seems there's about a .8-.9 voltage drop. Under normal driving habits, with the stereo on (not loud) headlights, with one of the sets of pods on as fogs, and the heater on, normal readings on torque seem to range from 12.8-13.1, but never higher than 13.1

Couple nights ago, it was particularly cold, therefore had the heater on full blast with everything else about the same, and was sitting at a stoplight and noticed my voltage drop down to 11.2v.

I'm running a larger SuperStart battery and was running the O'Reilly alternators but got tired of replacing them, and am now running an alternator that was pulled from a wrecked 99 4Runner that had 130k on it, and am still seeing the same issue. I've also upgraded the battery to chassis ground.

Am I experiencing a legit issue here, where I'm having a problem with wiring or the battery? Or am I finally running enough electrical shit that it's finally come time that the factory alternator just isn't cutting it anymore?


Also, since I refuse to pay for Photobucket, anyone that wants to see what the rig looks like now is welcome to check my Instagram @notconnorwrong

 

[LittleCaesar]

Is the battery light on? Is the alternator belt tight enough?

I'd start by getting both the battery and the alternator tested at O'Rileys and go from there.

 

[wemslie97]

My Scangauge II was reading no more than 11.3v yesterday but was whining from the engine compartment for a few days. The alternator was so hot I don't know why it wasn't on fire. Belt is good...alternator...toast. Don't know if it's bearings or brushes or what but it's original with 166,000 on the clock so new oem is going in.

 

[wemslie97]

Oh, and no dash lights on! Another 20 miles and it probably would have had a melt down. Try touching the alternator after letting it cool down for half an hour or so. Should only be very warm at most.

 

[3bears]

I think your running too much power needs.
with all that you might have to update to the CS144 alternator mod.

Also the torque pro does read a tad low on the voltage #'s.

 

[theesotericone]

Am I experiencing a legit issue here, where I'm having a problem with wiring or the battery? Or am I finally running enough electrical shit that it's finally come time that the factory alternator just isn't cutting it anymore?

Like stated above, get the battery and alt checked. If your battery has a dead cell that will cause the alt to full field all the time. Full fielding is a very easy way to fry the alt. By your numbers the alts already a goner but I'd make sure the battery is good.

I'm running way more RMS and have a ton of aftermarket electronics including a winch. My stock alt handles it all no problem.

 

[TheOGConCon]

Like stated above, get the battery and alt checked. If your battery has a dead cell that will cause the alt to full field all the time. Full fielding is a very easy way to fry the alt. By your numbers the alts already a goner but I'd make sure the battery is good.

I'm running way more RMS and have a ton of aftermarket electronics including a winch. My stock alt handles it all no problem.

I'll take the battery to get it checked tomorrow, as well as do my own test with a multimeter. I just put in this alternator, albeit it is used. Glad to know the stock electrical output can handle it. What battery are you running?

 

[TheOGConCon]

Is the battery light on? Is the alternator belt tight enough?

I'd start by getting both the battery and the alternator tested at O'Rileys and go from there.

No battery light, alternator belt was checked by dealership. I know the alternator was good when I put it in a couple weeks ago, had it tested prior to install. Battery is next to check

 

[TheOGConCon]

I think your running too much power needs.
with all that you might have to update to the CS144 alternator mod.

Also the torque pro does read a tad low on the voltage #'s.

That's been on my mind, just not sure of a good place to source a quality CS144. No junkyards nearby have any, and the last adventure I had with part store alternators has left a sour taste in my mouth. eBay also has a host of high amp alternators for our rigs, which I'm also unsure of pursuing.

 

[19963.4lsr5]

You should verify the voltage at the battery with a multi meter. My 4Runner will run all day at 13.89v-14.02v with radio-lights-heater on speed 2 at idle in gear with brake lights on too.

I read the voltage at the cig lighter. My 96 saturns system voltage according to my ScanGauge (ICM voltage) ran almost 2v lower than at the battery posts.

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[TheOGConCon]

You should verify the voltage at the battery with a multi meter. My 4Runner will run all day at 13.89v-14.02v with radio-lights-heater on speed 2 at idle in gear with brake lights on too.

I read the voltage at the cig lighter. My 96 saturns system voltage according to my ScanGauge (ICM voltage) ran almost 2v lower than at the battery posts.

I have done a comparison side by side between torque pro and a multimeter and found just shy of a 1v drop between the battery and the OBDII reader. Taking that into account, I'm still dropping to barely above 12v while at idle at a stoplight with the heater, headlights, foglights (30w led pods with Amber covers) and stereo at moderate volume.

 

[19963.4lsr5]

I have done a comparison side by side between torque pro and a multimeter and found just shy of a 1v drop between the battery and the OBDII reader. Taking that into account, I'm still dropping to barely above 12v while at idle at a stoplight with the heater, headlights, foglights (30w led pods with Amber covers) and stereo at moderate volume.

Moment of silence for your charging system most likely.

Edit. Set the ebrake, put in gear and turn on all your stuff and check the battery post voltage and compare it the the voltage at the alt output post. Make sure there the same during low voltage condition to eliminate bad connections in alt of the under hood junction box.


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[Pioww]

I would check the grounds. Considering the corrosion that these vehicles can incur, you may consider running extra grounds, especially when you have high power requirements. If you run the big three and that makes an improvement, that would give you your answer, to the cause. There is a tool like a power probe, but it has another name load pro I think, that is good for measuring circuits with a load applied. It is hard to find this issue, if it is a bad ground issue, without checking each ground, to see if it is the cause. Good luck.

 

[floatingkiwi]

I've found a bad ground from the battery to the body, even though the factory crimp looks good (and we dont have corrosion here).

So:
load up your electrics with your lights, rear screen heater and suchlike, and check voltage drop over the ground point from battery terminal to the actual body. It should only be mV range. I had 0.5V depending on load. Bad... And it was getting too hot to touch.