Bad Alternator?

[astach]

In my 97 2 door sohc explorer sport i just started noticing that i was getting huge voltage drops while idling. Granted i do have a system in the back, I have done the "big 3" wiring upgrade also, this just started happening a few days ago. Today while driving i noticed that while idling and driving i was seeing a voltage of 12.2-12.4 V. Every so often when pulling away from a light it will bounce up to the normal 14.4-14.6V but then it will just fall back down again. i have had this system for well over a year now but i never noticed anything like this, since i saw this i have disconnected the amps and everything to see if that would fix it but nothing has changed. The battery is less then a month old.

Am i going to be looking for a new Alternator or should i just have auto zone check it out? If it turns out to not be a bad alternator, what else could it be?

 

[BrooklynBay]

It sounds like a bad alternator. You could have Autozone test the alternator, and load test the battery just to be sure. What brand is the battery?

 

[astach]

I took it over to autozone and had it tested and they said it was fine. So on the way home i made a right turn and everything started working great, but when i made a right turn down my street it started doing what it was doing before. the only thing i can think of is a broken wire somewhere. The autozone employee thought it could be the voltage regulator, would that cause this problems also?

 

[BrooklynBay]

The regulator is internal, and is tested at the same time as the rest of the alternator.

 

[cfd911]

voltage reg

yes that s true it could be a bad voltage regulator, electrical components do not respond well to heat, so think about this , you take your alternator out of your truck it cools down the guy puts it on the machine to test it he tests it for about 15 seconds and shows a basic test that the diodes, rectfier and alternator is putting out the right amperage, so it passes. you go home put it back in your truck , you now have it on a constant heavy load continuiously even with your nice radio and subs going then you add that the alternator is under the hood where engine compartment temperture is significantly increased now you are increasing stress on a component that is weak and you very well could have a bad component.

 

[cfd911]

but

definatly check all your conections to the alternator and check that wiring too.....

 

[cfd911]

just for chitz and giggles

just for fun i tested my batt and alt he s what i had.

newer battery 6 mths old truck off doors closed battery voltage 12.5 volts

truck idling 14.3 volts truck high rpm ( 1500 rpm) 14.5 volts.

so your 14.6 is good while running your 12.2 is BAD BAD BAD WHILE RUNNING so yes i would check all your connections and while the truck is running use a volt ohm meter at the battery and check the plug at the alt wiggle it see if you get a volt drop .......

if everything checks out ok then turn on your head lights and your stereo and amps and check your voltage , if it seems low 12-13 volts rev your engine and if your lights flair up and the voltage goes up your alt can t keep up with the load so your alt is too small or your alt is bad and also remember your alt output is only approx 1/3 at idle as rpms go up then your alt output will improve at needed.....

 

[astach]

Me and my father both checked out all of the wires and everything, but could find nothing wrong with any of them. So we just replaced the alternator and now everything is running like it was before. I still cannot figure out why the tests would have come up good when in truth replacing the whole thing was the only fix we could find.

 

[cfd911]

like i said

like i said before when you put a constant load on that alternator it heats up then you have it under the hood with hot engine temperture that might aggravate the the problem of a faulty componant remember solid state electronics if their gonna fail they usually do when they are heated up ie overheated or just normal wear and tear and heating up from normal use...

 

[LarryT1]

I see if your sig you dont say anything about having capacitors in your system, you should invest in one so it takes the hit and not your battery. a friend of mine had the same problem with a big system and no capacitor. I've been running the same system as his in my ex with a cap for 6 years with no charging problems at all.

 

[astach]

I see if your sig you dont say anything about having capacitors in your system, you should invest in one so it takes the hit and not your battery. a friend of mine had the same problem with a big system and no capacitor. I've been running the same system as his in my ex with a cap for 6 years with no charging problems at all.

I forgot to add that in i have everything running off a 4 farad capacitor. I have had it in for awhile but i never had problems till the other day, but with the new alt everything works great.