Voltage Drop Issue

[InfiniteGSX]

[ame=http://www.youtube.com/watch?v=eaUw28PdiOY]Wtf? - YouTube[/ame]

I've brought this up before and everyone said "alternator", "battery" bla bla bla. Well I've been working with electrical equipment for.. .well my entire life. Alternator is good, holds on a good battery at around 13.8v. Which is how it should be. I got a new battery a short while ago, and it didn't do it. I hit the blinkers and everything and no dimming, while engine off. Well actually it was when there was no motor in the car. I got the car running and its back. So I just now today had the battery replaced. Luckilly they let me chose a more powerful battery. I went from a 650cca to an 800cca. Glad I have warranty. Well it still does it. So I put it on a battery tender, it signaled it was within 80% charged and then a couple minutes later it went to storage mode....Which means its fully charged. Still blinks like this.

Notice when I hit the emergency lights (which signals both left and right front and rear high beam signal lights) it doesn't dim as much as when I just hit left or right.

I mentioned in the last post I made, that I've always had this. I've owned 9 DSM's in my lifetime and have never seen one not do it, except the time I had no motor installed.... But I know for a fact this isn't how they came from the factory and other people have told me their cars don't do it. So WTF is it? It really bugs me.

Weak Fuses? Weak Relays? Damaged Signal Boxes? Bad Connection To battery? Some people say bad ground, well please be more specific because I have one hell of a grounding system. I have a legit 2ga battery cable going directly from the battery's ground to a metal block (grounding station which is bolted straight to shaved metal for a perfect battery to body ground. And then two 4ga battery cables bolted to this grounding station, one going to the middle bottom Intake Manifold Bolt. The other goes to the Starter/Transmission Bolt.

Any idea's from people who have eliminated poor voltage issues like this is greatly appreciated. Tell me where to look and I'll get on it first thing.

 

[Jward5]

Sorry to hear this man. All that comes to my mind is you have some cracked/bad wires in there somewhere. Id start by uncovering the wires going to your blinker lever or whatever you want to call it and trace them back and see if you can find some cracked wires that could possibly be arching. Good luck with it.

 

[PieEyedPiper]

I've never been in a DSM that didn't do that. I was not fortunate enough to give a dealership lot car a try but I'd bet money the cars did it when new, too.
It's a 90's thang.



I plan to install LEDs in place of almost all the bulbs. The reduction in amperage required should produce a result.
Did you test to see how much vdroop you're getting?

When someone tells me that their car doesn't do something, I don't usually believe a word of it until I see it for myself. I'm constantly amazed by how oblivious, or just plain 'ol too uninterested people are to notice that blink, or hear that creak or whatever it is, etc.

 

[bkiel]

I'm running a small battery, and I can watch the rpm's fall at idle with brake lights on, then headlights drop it further. Signals make my fuel pump pitch up and down. I have a 1gb but same kinda thing.

Mine as well, brake lights drop idle. Headlights on it drops further. Turn signals has an oscillating effect to the fuel pump.

 

[NHerron]

Concerning your video, (didn't read sorry) I have the same exact thing going on. The cars been out of commission for a while now for tons of mods and upgrades, and this was one of the top things. To remedy this:
I am replacing the DSM alt with a Saturn.
Replacing the alternator output two 8ga wires to one fat 4ga welding cable.
Replacing the 4 8ga wires running from fuse box to battery with two 4ga welding cables.
Crimp then solder every terminal.

Stock alternator output cables drop .5V @ 100amps FYI.

 

[Pale Horse]

I was just going to suggest replacing your alternator to battery, battery ground, and chassis grounds with much larger wire as in the "Big 3" upgrade. It's possible one or more of these wires is the culprit to begin with and even if they aren't totally at fault, perhaps the larger AWG would aid in the voltage drop.

 

[Joethefallen23]

To resurrect the old horse, I too have a very similar experience. Using the turn signals results in the same oscillating effect shown in the video. Brake lights produce the same drop. Having access to a load tester (and an expensive one at that), entire charging system checks out. Idles at a rock steady 14-14.1 volts. Applying the brakes induces and instant drop to 13.2-13.3 volts. Granted, I understand the taillights apply a decent load, but close to a whole volt drop across the board? Seem excessive. No fuses blown. It does recover to high 13 - low 14 volts while I continue to hold the brakes.

90 amp Galant alt (new brushes), 4 gauge to the fuse box and two 6 gauge to the battery. Grounded to the firewall, transmission, both strut towers, the throttle body and the CAS cover.

It just seems like an excessive initial drop and easily dims the light when stopping. I can't seem to find a wiring issue, but it certainly doesn't seem like a positive arc to ground, otherwise I would have popped a fuse.

Anyone have any clues or is it just something to deal with? I haven't driven my other GSX in a while and can't recall ever having this issue (to be fair, I've had bigger diagnostic issues to deal with over the last year or so).

 

[Mello]

Both my cars do this. I think this is normal.

 

[Joethefallen23]

I see. Has anyone here ever had the chance to measure the actual drop though? It just seems like a massive drop in voltage in my opinion. I can understand at idle but it even dims the lights at highway speeds.