PLEASE HELLLP!!!!

Ok, so i got an 85 z28. LG4. blablabla

Point is, few months ago, my brushes died, so i rebuilt my alternator. and life is good. (and battery is a year old)

Then, last week, my voltage started to slowly die down to about 8-10 and it really scared me. So i just automatically assumed, maybe i didnt do my alternator right. So i got both alternator and battery tested. and my alternator is putting out 15.38 volts at 78amps and my battery is putting out 649CCA (19 more than the sticker says)

So both are good. So i put it all back in my car, and its fine.... for a week... and now its starting to die back down again.

Now all my connections are good as far as i can tell, i even replaced that alternator connector, and cleaned terminals, checked starter cables. im at such a loss!

Also, my alternator DOES charge, when i first start the car, the voltage used to go upto 15 or 16 then die down to 13 (around a week ago) and now it goes upto about 13 or 14 and dies down to 10 or 11 or something... So its working.. but not enough...

I did do current draw tests, when car is off. nothing on. theres 0.003 amps of current (clock in the radio i guess) and i checked current at all my fuses and everything is taking the amount of power it should be. Im at such a loss!!!

Now i have a roadtrip to go on this weekend in the car. and I really need to be able to depend on it! lol

 

when the voltage drops are you checking with a volt/ohm meter of some sort? i ask because my car's volt gauge was doing the same thing, when i check with a dvom it was fine. you could have a loose or corroded connection somewhere and the alt could still be bad. the alt problem could be weak only when hot.

 

I just checked the voltage at about 5 points in the car (including battery) and everything was within .1-.3 volts.

I just checked the voltage drop of EVERY wire conncted to the battery (from top post, to starter so it would include side post resistance) and everything was liek .01 voltage drop or something. Completly fine, all connections are tight, clean, perfect. i cannot figure it out.

The only thing that im not sure about is the brown wire going to the alternator, its the one that goes to the engine wiring harness and that goes to the volts gauge i believe. thats the only wire that could.... possibly be a problem....

Also, the alternator DOES CHARGE, when i unplug the connector on my alternator, the voltage drops. (not by alot, but it does, and engine sounds better) so the alternator is presenting a load, and charging. but just not enough!

 

I had almost the exact same thing happen last week. Went from charging at 14.4+ volts to 12.5 or less- mostly less.

Turned out, when I installed my new intake, the choke wire (powered from hot in run plug on my alt) was crushed by a heater hose, and created a small grounding situation. Removed the choke wiring, and volts shot back up.

I drove about 400 miles with it before it started dropping charge, and it was very slow since the hose had to work through insulation on the + and - wires to the choke.

 

Well since i replaced the grounding wire bolt right below the alternator, all has been well... Im sure ill find out how itll do on the 700 mile trip this weekend.

 

Ugh, No dice. Drove home 20 minute drive today, with the lights on. and voltage just slowly dropped to 11.

anyone have ANY idea? I dont care how much it costs to fix. i just NEED rely on this car!

 

First off, you must know that you're reading of over 15 Volts means it was charging the battery
Normal off is between 12.4x and 12.5x+ or so
Normal readings with the engine running should be between 14.4 and 14.7V or so, it's not exact
If you are not in this range, after Knowing that the battery is fully charged and all the accesories are turned off.....you have to do this to check for a parasitic draw

Pull the Negative post off of the battery........connect a Test Light between the Cable and the Battery Post....is there a glow of some kind on the test light? Start pulling fuses until you find the circuit that is drawing power.....that is the circuit that has a short/bad wire/bad part

Good luck

 

I did that, theres nothing.

 

After a week of sitting, with a weak battery, it is possible that you could have trouble starting your buggy
It is also possible that even with a new battery you need to run it more often

My wife's car gets started every day but run only 6KM each way that I had to buy her a solar charger to keep the battery charged up enough that we no longer go through battery/alternator changes every couple of years

 

I drive the car everyday, I usualy do about 400KM a week.

Its just that the battery is slowly dieing, due to it not being charged enough (for reason we are trying to figure out)

 

I know you said your battery tested good, but have you checked the water level in your battery lately? One more thing to look at if you haven't already.

Do you have a system in the car by chance? I've seen amps that drained a battery down by running the wrong trigger wire to them.

 

I have a very small sub, takes up abou 9A of power. and its functioning correctly.

i have checked this too..