Alright, first of all I did a search for the problem I was having and could not find anything.

Now, my voltage started acting up few days ago. First the car would not start, and the negative wire on the battery was extremely coroded. It was so coroded that I could not unscrew it. I ended up taking the whole cable out and replacing it with my 79 firebird negative cable. I put in an 80dollar energizer battery almost twice as powerful as my original one. Now usually the voltage is around 14-14.5 when I am driving, however when I idle it drops to abour 13. It usually drops when the lights are on. During the day there is really not that much problem, it never drops lower than 13.5. However whenver the blinker is on the voltage needle fluctuates with the blinker (kinda cool). So I was wondering what the hell would the problem be. Here are few conclusions that might be the culprit. It also drops if I brake hard.
1. Bad alternator (on its way out)
2. The bracket that was holding the alternator to the exuast manifold is removed due to headers. This might be a problem.
3. The negative cable that is suposed to be hooked to the frame from the negative terminal is not hooked up, its just closed up.
Now, I am going to connect the cable tomorow, and check if that was the problem. It did work fine on my 79 bird without the cable being hooked up to the frame. I was just wondering if this sounds like a connection problem, or more like an alternator problem?? Also I am not sure if that bracket does whole lot with the power, it might loosen the tension to the belt and therefore it might not be working properly???
Please help???

 

cable should be ok attached to the engine any ground point would work just fine or else it would be dead all the time.

alt bracket could be a problem if the belt is loose and allowing it to slip some it will not put out a full constant charge that way. watch it while running is it moving around at all if it does wiggle and move i would work up a new bracket.

most likley alt is going south. did you clean you term on the battery ends positive and negative? doesn;t take much corosion to mess things up.

 

Are you taking the voltage reading from the dash gage? If so ignore, anything it tells you. Get a DMM/VOM and check with that. This is common.

 

well, I did ground that little wire that comes from the negative terminal cable to the body. I also noticed that my negative connection was pretty loose, it took me about 2 full turns to tighten it (hand tight). Than I started up the car, my voltage was a bit higher almost at 15. I turned on the fan and the lights and the needle barely moved. So, I think I am doing good now. Also, I checked the bracket and if the alternator moves or not, but its solid on there. It moves to the right with the whole engine, but so do all the rest of the accessories.
My positive connection on the alternator does not have the plastic boot over it, which might be the problem and I seem to always ground the positive connections when I try to tighten them. There are always sparks if I barely touch anything else while messing with the bolt. Thank *** I did not get shocked.
I am going to drive it and see how everything works out.
I noticed as well that the connection on top of the alternator is not cliping into the place anymore, so i might have to change that as well, but its stuck in there pretty good.
I will be back with updates.

 

the body does need to be grounded, there should also be atleast 1 ground from the motor to the body too. running without atleast 1 body ground somewhere can damage the gears in the rear end, the slip yoke and the transmission along with causing other electrical problems.

 

Good point! I did ground it to the body as well as the engine. I tightened up the connections and it seemd to be working a lot better. It does, but when its under load and all the lights it tends to drop whenver I break harder or when I first shift after I started the car. Mind that all of these problems come at night whenever I am using the lights and all...
I dont know what to do, it goes to just below 13v, when I hit the brakes a bit harder to stop. If I stop normaly it will stay pretty consistent. What do you think the problem might be?? I will have the car tested in two weeks, but untill then I am contemplating of getting a new alternator.
Also, would a stronger alternator be better???

 

OK xlw,
Try this:
1. At the rear of the passenger side cylinder head (next to the firewall), see if you can find some wire lugs bolted to the head.
2. If you find these wires ( one if them is the ground wire that connect the dash gauges to engine ground), unbolt them from the head and scrub all the metal lugs clean with ScothBrite or Med-Fine grit sandpaper.
Also clean the suface of the cylinder head around the bolt hole.
3. Reconnect the wires and see if your problem is fixed?

If this does fix your problem please let us know so other third gen owners might learn from your experiance.

If NOT then we will keep tring to help you.
Do you have access to handheld voltmeter? Having the proper tools too troubleshoot can save a LOT of money from being spent on un-needed parts (like replacing an Alt that is not bad).

 

ok i gotta ask... how does a ground wire affect a rear end? there must be some logic to this so before i say bs i may learn something here.

thanks

 

 

I think what Denn meant to say:
If the engine to body ground strap is not connected, the transmission shift cable can fry because it is the only metal connection from body to engine and ends up carrying all the Alt current.
This has happened alot!

 

Am on it!!

 

Ok, I was working this whole weekend, with no time to do anything. I figured out what the big problem is with the charge. When I got my headers installed, the fan sensor was just broken, so I use the fan switch that was t-ed from the green/white wire. It was grounded to the metal that was on the transmission. Every time I turned it on the voltage would drop. However, it will only drop if the car is not moving. It will drop to about 13 and a bit lower, and it would climb up just a bit above 13. If I dont stop to violently the voltage is always above 13, and if I stop violently it will drop to just a bit lower than 13. I switched the ground away from the tranny and put it to the body. The charge is a bit better now...However, I will try to check those wires out tuesday and try to clean them, it shouldnt be a problem. Just want to let people know that I am not giving up on you.
There are way too many threads that dont end up with an answer.

Thanks.

 

I did it and it did not change anything. At least not that I noticed. I found bunch of wires grounded to the drivers side of the head and cleaned them too. It just seems like when the fan turns on the voltage drops to just below 13 and than it climbs back up, and stays around there. Whenever I idle if the voltage drops it will climb back up immidiatelly to 13.5. Which is good I guess. The cleaning of the connections really doesnt hurt your system and I would recomend it none the less.

 

Is this still happening after cleaning the grounds?

As long as the voltage is over 12.5 volts, the battery is not being drained, so I would not worry too much.
You could have:
1. A bad Volts gauge.
2. A weak Alt.
3. Low idle speed.

What it the engine RPMs when the voltage is low?
Do you have acces to a handheld Volt Meter?

 

Whenver the engine warms up the idle is about 600-700. If the voltage drops I can hear the idle lower a bit. However not too much of a problem. I will be getting a new alterntator anyways, so Illl update the status of it.

 

slap me if im confused on this but u say ur voltage is pulsing with ur turn signals....do ur head lights also pulse...if so ur voltage regulator is out...check on the back to see if its external...youll be able to tell....if not youll need to get a new alt

 

You mean check on the back of the alt. for voltage reg. What is it and how does it get shot??