Volts Dancing (Udate: Video Link 1st Post)

2005.Neon.SXT · Post by **2005.Neon.SXT** » Wed Sep 14, 2011 11:25 pm

Ive had this issue for a couple of years now, but want to know if any of you had this situation. My voltmeter dances all over the place, from as low as 13 volts to as high as 14.2 volts. My gauges, exterior lights (minus HID's), dome light, etc flicker as the needle bounces.

Things I've done: just recently (last week) did the "Big 5" upgrade and have 4awg wire in place of the stock grounds. My buddy and I tried to eliminate ideas of what it could be by unplugging the radio, HID's, pillar gauges, alarm, gauge cluster, etc and nothing seems to remedy the situation (my lights still flicker). I have had my alternator and battery tested and nothing seems wrong with any of them (battery is a year old).

So... Ideas?

*** EDIT ***

Here's the video link: http://www.youtube.com/watch?v=iS_qgYzgNCQ

I have no idea what to make of it... if you watch the cluster closely, you'll see it dim... and for those who can't see that, I showed the voltmeter gauge.

Thoughts?.... I know I've made like three threads about this, which is why I'm bumping this, but I just want my car to idle at a fixed volt... not a range from 13.00 to 14.15....

mwenzlick · Post by **mwenzlick** » Thu Sep 15, 2011 1:09 am

Mine does the same, but seems to average around 13.4 - 13.5, i have never seen anything above 13.9 but and as low as 13.2.

nineball · Post by **nineball** » Thu Sep 15, 2011 11:40 am

anything above 13 is fine. get worried if it drops to 12 or lower.

xbrandonx · Post by **xbrandonx** » Thu Sep 15, 2011 2:07 pm

my cap flutters around the same..

2005.Neon.SXT · Post by **2005.Neon.SXT** » Thu Oct 13, 2011 9:53 pm

Bump. Added video in original post.

nineball · Post by **nineball** » Thu Oct 13, 2011 9:57 pm

you can hear the revs drop when the needle drops, so i doubt it is the meter. sounds like you have a lot of trouble shooting ahead of you. wish i could be more help.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Thu Oct 13, 2011 10:31 pm

Ya, you can "hear" it... But unless it's very minimal, my tach doesn't budge.

mwenzlick · Post by **mwenzlick** » Thu Oct 13, 2011 11:37 pm

Have you checked the voltage with an actual multimeter?, i have the glowshift LED volt gauge and it is about .1 - .2 volts off and flutters sometimes. it may not be completely acurate based on where it is hooked to as a source.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Thu Oct 13, 2011 11:48 pm

I was thinking that but then why would my cluster, dome light, brake, reverse and turn signals pulse/dim? If the gauge was faulty... This has been such a mystery to me. No one seems to know the answer...

mwenzlick · Post by **mwenzlick** » Thu Oct 13, 2011 11:57 pm

hmmm. i hate to spout out the obvious but have you checked

connections at the alternator
battery terminals clean and secure
all major grounds are clean and secure
no shorts anywhere

other than that, all i can think of is having the alternator tested

2005.Neon.SXT · Post by **2005.Neon.SXT** » Fri Oct 14, 2011 8:07 am

Alternator has been checked, tested and tightened. Just upgraded my grounds to 4awg, and cleaned where they're bolted. Battery is a year old. Back when this started happening, I swapped in a JY alternator and it helped for a little, but not for long.

I've checked my connections and wiring for my cluster overlay, Alpine headunit, pillar gauges, alarm system wiring, and everything I could think.

ZeroChad · Post by **ZeroChad** » Fri Oct 14, 2011 12:16 pm

The PCM uses the signal from the IAT or the battery temp sensor on NGC. If this signal is irratic or non existent, it will mess with the field signal the PCM sends to regulate the alternator. When I had my IAT sensor disconnected from the pcm, the alternator voltage was lower than normal and would fluctuate a lot.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Fri Oct 14, 2011 2:09 pm

ZeroChad wrote:The PCM uses the signal from the IAT or the battery temp sensor on NGC. If this signal is irratic or non existent, it will mess with the field signal the PCM sends to regulate the alternator. When I had my IAT sensor disconnected from the pcm, the alternator voltage was lower than normal and would fluctuate a lot.

I don't have a battery temp sensor (that one that plugs in the back of the blanket), but I did put the blanket on a couple days ago. I had taken it off a couple years ago, but putting it back on hasn't done anything.

Can the IAT sensors go bad? They hard to replace?

*EDIT*

Also, is there a voltage regulator in the PCM that can go bad? My buddy at the shop said that may be a possibility?... It just irritates me when I'm sitting at a stop and my lights are just flashing at me... constantly. I don't have a sound system anymore, and it was taken out a couple years ago.

... I'm gonna figure this out, dangit lol.

Post by **occasional demons** » Wed Oct 26, 2011 8:04 pm

I was behind a Honda tonight, lights dimming about 3 to 5 times per second.

It could very well be the VR in the PCM. Possibly over/under shooting the target voltage. If it only does it with the engine running, I would lean towards the PCM.

It would take a few dollars, but you could get a VR from the mid seventies to early eighties set up, and splice into the field control of your alternator, and bypass the PCM. The VR must be grounded tho. But if the voltage stays steady, you know it is a PCM issue. Whether or not it is worth replacing the PCM to cure it, is another matter.

http://chucker54.stores.yahoo.net/oemuscarvolr1.html
http://chucker54.stores.yahoo.net/volreg.html

http://www.repairconnector.com/products ... gtail.html

Edit:
viewtopic.php?t=46797&

Post by **occasional demons** » Mon Nov 14, 2011 10:07 pm

Took note of another possibility today. Battery was dead in the Jeep due to an interior light not shutting off. I jumped it to move it closer, so I wouldn't have to carry it as far to the battery charger. I noticed the lights flickering, and the volt gauge bouncing at 14. It is normally rock solid. once I got the battery charged it is back to it's normal self.

Possibly the battery is borderline, causing the alternator to be in a constant state of charge. The VR is hitting peak, and backing off, back and forth. If the battery loses it's internal resistance, it will not stabilize the voltage like it should. So the VR has to hunt, to maintain the target voltage level.

If this is the case, the battery is running the alternator to death. I have seen a few cases of the battery being replaced, and the alternator failing a few weeks later.

The only way you would realy know if it is pulling from the alternator, is an amp gauge, and checking for an amp draw specifically to the battery would take a healthy amp gauge in series, or a meter with a DC amp probe. Those are not cheap. In any case, it isn't a simple/cheap thing.

nineball · Post by **nineball** » Mon Nov 14, 2011 10:47 pm

good thought. my dad's old liberty had similar symptoms (weird gauges, etc) and it was the battery too.

on the other hand it seems weird that it would be so rythmic and consistent but you never know.

Post by **occasional demons** » Wed Nov 16, 2011 8:14 pm

I think the consistent rythm is the VR over and undershooting the target voltage, due to the battery not keeping some sort of stability.

I have seen old school VR's go above 16 volts with a battery with low internal resistance. It was one way of diagnosing a bad battery that otherwise seemed 100% normal. What I got from it, is a good battery should regulate itself at a max of around 15 volts.

This is with a standard "12 volt" charging system of course. Newer electronic VR's do a much better job of controlling the voltage, so the over voltage scenario is much less common. The flickering lights may be the tell tale sign tho. But it is just a theory.

BigMac · Post by **BigMac** » Fri Nov 18, 2011 1:50 am

2005.Neon.SXT wrote:Alternator has been checked, tested and tightened. Just upgraded my grounds to 4awg, and cleaned where they're bolted. Battery is a year old. Back when this started happening, I swapped in a JY alternator and it helped for a little, but not for long.

I wonder if maybe the wiring connector is corroded, and pulling it off and pushing it back on cleaned the contact surfaces a bit which fixed the problem temporarily. You might want to try disconnecting and reconnecting it a few times to see if that makes any difference.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Sat Dec 03, 2011 10:49 am

Bill, regarding your comment in the other post, mine didnt come with a battery sensor blanket. Just the IAT.

My battery is about a couple years old... What would getting it "thoroughly" tested involved? I did a test with a multimeter, and everything checked out as far as that goes.

I've not checked spark wires or alternator wires yet.

Post by **occasional demons** » Sat Dec 03, 2011 5:17 pm

I think it was only the '03's that had the blanket.

Somewhere like AutoZone, or a battery place can load test it to see if it keeps voltage above a certain level for the specified amount of time.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Sat Dec 03, 2011 8:56 pm

occasional demons wrote:I think it was only the '03's that had the blanket.

Somewhere like AutoZone, or a battery place can load test it to see if it keeps voltage above a certain level for the specified amount of time.

I've had that done numerous times, with the old battery and even after I got this current battery installed. According to AutoZone and Advance Auto, both my alternator and battery test out fine... *shrugs*

stringburner · Post by **stringburner** » Thu Dec 15, 2011 4:06 pm

I have an '03 R/T that does the exact same thing. I've had it about a year & a half, and i've always noticed that the voltmeter (same as the op's, "Glowshift") drops a good bit when I roll up the power windows. Same identical needle flutter as the video, but I noticed it while driving mostly. Lately, probably because it's gets dark a lot earlier, when I first start to drive the car, there is a subtle, very rapid strobe effect to the headlights and cluster lights. It kind of messes with you and you think it's your eyes, but it's there, and seems to go away after the car warms up a bit. It also took one fit for a day or so where the voltmeter would bottom out to zero after rolling the windows up, then bounce back to the normal range. Hasn't done that for awhile and only that one time. I agree that it's annoying. O_o

nineball · Post by **nineball** » Thu Dec 15, 2011 4:08 pm

stringburner wrote:I have an '03 R/T that does the exact same thing. I've had it about a year & a half, and i've always noticed that the voltmeter (same as the op's, "Glowshift") drops a good bit when I roll up the power windows. Same identical needle flutter as the video, but I noticed it while driving mostly. Lately, probably because it's gets dark a lot earlier, when I first start to drive the car, there is a subtle, very rapid strobe effect to the headlights and cluster lights. It kind of messes with you and you think it's your eyes, but it's there, and seems to go away after the car warms up a bit. It also took one fit for a day or so where the voltmeter would bottom out to zero after rolling the windows up, then bounce back to the normal range. Hasn't done that for awhile and only that one time. I agree that it's annoying. O_o

have you upgraded your engine grounds? that does quite a bit to help that draw when using windows or when first turning on the rear defrost. when i first did mine with 4g it was a dramatic improvement.

stringburner · Post by **stringburner** » Thu Dec 15, 2011 5:46 pm

I have not, but I'm going to do that soon. I've been in school & working for the last couple years, so there hasn't been a whole hell of a lot of time for much of anything. I have to put a timing belt on it w/in the next 1000 miles or so, so I'll do the ground upgrades @ the same time. I haven't looked for a how-to on the ground upgrades, but I'm sure the information is here w/ a quick search. I got rear-ended a couple weeks ago, so i haven't been driving it, therefore it hasn't bothered me much lately. ( ; As soon as I get it in the shop and get it fixed I'll work on the rest of the stuff.

Thank you for the reply.

nineball · Post by **nineball** » Thu Dec 15, 2011 5:47 pm

stickied in the electrical section of the how-to forum.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Thu Dec 15, 2011 5:51 pm

Engine grounds didn't help in my case. Mine still flutters in voltage. Did all 5 grounds.

stringburner · Post by **stringburner** » Fri Dec 16, 2011 4:30 pm

nineball wrote:stickied in the electrical section of the how-to forum.

Thank you sir. ( :