well here is my delema, my battery is bad and i have to jump start it everytime i need to start my truck, so i was wondering if i have to jump start is because the alternator is failing. so i was going to test the alternator, but it is covered in about an inch of sludge. so instead i had the idea to unplug the battery and put a meter on the battery wires while it was running, but when i took of the battery wires it stalled.

then i thought that maybe since its efi (my engine is a 22re/ 85 pickup btw) it just needed the battery on to run the efi or something like that. then my brother told me if it stalls when you unplug the battery, your alternator is bad, wich makes sence because if the alternator was good it would keep the engine running.

now i would like to present this evidence. my truck will run fine for about a half hour, then it will start to sputter and cut out above idle, after a while, the lights on the dash will come on like it has stalled when its still running. now that brings us back to it stalling without a battery. maybe if my lights and stuff are killing the battery, then after a half hour the battery is dead, so it doesnt have any juice to keep it running. and i know the sputtering and such is related to power, becuase it has more power and sputters less with the lights off, then when i turn the lights on it will want to stall.

so do you guys think i need a battery ( well i know i need a battery, but is that causing the problem?) or an alternator, or both? just tryin not to spend money on an alternator if i dont need one ya know...so thankd everyone.

 

 

if it was just the battery the truck should run fine off the alternator, (for a while) but when you turn it off it wont start again.

even if you battery and alternator were both brand new, if you disconnect the battery while the car is running, it will stall. every car does that. the battery completes the circuit. so thats not a good test.

a good one is to use a multimeter.

start the truck so its running and test the voltage when the truck is running. a good alternator should be putting out about 13.5 to 14 volts, thats how it charges the battery.

anything less then that i would say a bad alternator. how old is your battery? if its older then 4 years you should replace it anyway. but take a battery out of a running car and swap it in see if anything changes. that will tell you if your battery is bad or not.

 

I have never known of a single car that will stall if the alt is good and battery is pulled.



in fact I have driven home a couple of times with out a battery on a good alt.

 

I agree, if your engine stalls when battery is disconnected then yur alternator is not connected or working correctly.

the battery does not complete any circuit to the alternator. the alternator connects the circuit to the battery. the alternator is grounded to the engine block and the positive to the alternator is connected to the battery terminal which is connected to the fuse box.

Where on earth does the battery connect any circuit?

want proof, I will go out and disconnect my battery and you can watch my truck still run. I can also do this with my BMW although a little harder to do since battery is under back seat.

 

simple series circuits.. but not on modern automobiles

 

clean the brushes inside your alternator the sludge that you say is on the outside is in it aswell ...mine had the same symptoms you described cleaning the brushes saved me 260 kangaroos on buying a new alt

 

okay, i will definatly clean my alt. ill let you know if anything changes. any good ways to clean it (air compressor, windex, etc.?)

 

so, long story short, my alternator is bad because it wont run without the battery?

 

yea thats exactly right its the easiest way to tell...take the alt off then the plate off the back of it ..its just 4 small nuts a quick search on here shows how to remove the brushes clean it with what ever you like i used thinners just make sure its all dry and aired out again before u start the car

 

I most definitely didn't think that statement through. sorry for the wrong advice.

 

how about brake cleaner? is that too harsh?

ill do a voltage test before and after...im not good with meters, but do i set the meter to 9v?

 

dilute it with some water it should be fine n use hot water it will break down any oil or grease build up

 

alright thanks man, ill let you know how it turns out

 

heres pics of the alternator, i havnt got around to cleanin it yet, but prolly tomorrow. im on the lookout for a new one also, and a new battery. but ill clean it and see what happens.

 

I would take the alternator apart to clean it. I have had good luck using this stuff. It's pricey but perfectly safe to use and works pretty dang well:

http://www.autozone.com/autozone/acc...er=119711_0_0_

 

i found a nos alternator in pa, 17011, i think was the zip, its for an 83 corolla w/22re. he wants $40 and its.

 

Was just about to suggest lectra cleaner
Used it on my old old alt. and it cleaned the sludge off.
too bad the thing was still dead lol

 

There are so many things that may be wrong. If it is the charging system you should get the light right away

Agreed it could be the Alternator.

It could also be poor grounds

The battery terminal of the alternator these wires have a history of becoming burnt and brittle the plug on the alternator can get corroded both these things can cause a failure to charge .

Battery terminals could be loose or Corroded .

Do you have a Multimeter? Set on DC voltage in a range that lets you measure between 10 to 15 volts DC see what voltage you have across the battery terminals with the vehicle running should be from 13 to 14.5 depending on your meter.

Perhaps get the alternator checked at advanced or auto zone . I would hate to see all the trouble to change it if that is not the issue.

 

i was talking to my dad about this last night, he said, well isnt your battery light coming on???

it also started doing this when i got my "click but no start" problem...when i go to start it, it'll just click, unless the battery is over 12ish volts...wich is probably a bad wire right??