So about a week ago, i went out to start my truck and heard the clicking noise. tried a bunch of things and eventually cleaning my battery posts got it started up again first try. then just the other day it happened again. clicking and no start. Then i put in my other deep cycle and it started first try.
charged my battery up and it starts every time.

then ive been noticing my battery guage is looking pretty low.
Did a multimeter test on the bat. and im only getting 12.4 volts when idling.
i should be getting like 13 or 14 right?

so i got my alt. and starter and bat. tested. they said my bat is fine. My alt is shot, and my starter is going soon. he said the starter is drawing like 700 amps and thats whats killing my alternator.
does this all make sense to you guys?

is there anything i can clean or simply rebuild on the starter or alt. i was thinking about gettin a brush kit for the alt.

i jsut find it hard to beleive i need a new starter considering when my battery is charged i can start up no prob.

any and all advice would be great because i cant really afford a new starter and alt. at the same time right now.

 

A starter won't kill an alternator. A starter draws power from a battery to turn over. Once the alternator's spinning, it keeps the battery charged and runs other accessories as well. You should be seeing around 13.6 volts at the battery while idling. Have the alternator rebuilt and that should solve your problem. Might cost you a total of $100 to have someone rebuild it. At least, that's what I paid a good guy I know to rebuild mine.

 

maybe ill take my alternator apart and check out the brushes. is there anything else to watchfor in the alt? the commutator maybe?

any further tests i can do on my starter to diagnos that?
is it normal for a starter to draw 700 amps? he said it should be drawing a third of that and that i need a new one. he also is a salesman though

 

The contacts are burned in the starter very easy and cheap to replace them and there are lots of threads on here about it.
This is most likely the cause of the high amp draw from your starter.

Check out the brushes in the alternator.

 

alright i pulled out the alternator and the starter today.
the alternator brushes looked totally fine almost new even. same thickness as the new brushes i got.

anything else on the alternator it could be?
is there anyway that bad cables or clamps could restrict the charging voltage? My battery post clamps arent in the greatest condition.

i took the starter apart. the plunger and contacts were a little worn but barely at all. anything else in the starter that could be causing to to draw that many amps? That guy also coulda just been saying that to get me to buy one of his new ones.

i dont have a lotta experience but i dont think its my starter. when i have a good charged battery, itll start instantly no problem.

 

Another thing you can check the voltage at the two small terminals on the back of the alternator they are your field terminals. With the engine running you should have about battery voltage. If you don't you're voltage regulator is not working. You might also with a digital voltmeter check voltage drop from the battery terminal on the back of the alternator to the positive battery terminal. It should be very little drop though I do not know how much.

 

What year is your truck does it have a voltage regulator?

 

Having had an alternator repair shop from the late 80's through the mid 90's I would say somebody is wanting to sell you something instead of finding the problem. BTW, I have retested [for a second opinion] many "dead alternators" that were functioning properly but were replaced just to make a sale. I also believe that 700 Amps load would be close to melting the plastic insulation on your starter's battery lead. Get a second opinion from a reputable repair shop!

 

I would have to agree with all of this i thought you would find the contacts in the starter completely fried since they are not you need to check all cables and connections also make sure all connections are clean and bright.

This means grounds as well as hookups at starter and alternator also look for cables that may be corroded internally.

With all of this done again check for proper charging voltage and as well as proper field voltage at those two little terminals an the alternator.

 

alright so i took them to another shop. got em tested. they said the alternator was totally fine. brushes too.

the starter was pretty good but they replaced the contacts and cleaned up the brushes and the commutator. we were thinking yeah it must be my cables somewhere blocking the current cuase at the batt im only getting 12.3 volts

so i installed the starter and alt, fired it up, then tested the batt terminal on the alt and it read 14.3. so i started at the battery going down the cables testing to see where it dropped off. and i worked my way back to the battery terminal on the alt which was now reading 12.3. so if my alt is fine, then this is weird cause it should always read 13 or14 right?

 

Seems some things never change...

I think most of your problem has been resolved

NO. The alternator was first replacing the power removed from the battery from starting while at 14 volts. Likely it returned before your tests were completed. The alternator "replaces" lost energy to the battery while the alternator senses a load condition. The voltages vary with the loads applied. Your digital meter reading accuracy can also slightly vary depending on the manufacturer. Run it for a day or two and see how it acts.

AND you never did say what year the truck is??

 

oh sorry, its a 92. how do you tell if its externally regulated? i was prettty sure that it was.

ok so the battery terminal on the alt will only read 13 or higher when its charging the battery or when there is a load that requires that voltage? So its normal for it to drop down to around 12 when theres no load?

and ill try testing those two feild terminals. you guys said that they should be around 12 volts? and if not then i have a regulator problem?

My contacts all seem pretty clean. the clamps on the battery cables are a bit cracked, but ive cleaned them well and i can still get them tight enough that they wont budge.

 

Instead of fighting the 'load-no load' issue just turn on your headlights.
My DVM shows a consistant 13.8 - 14.0 at the battery with the lights on and it only drops .1 - .2 V a minute or so after cranking.

 

i just tested the volts again
12.44 at cold start idle. (at both the battery and the alt.)
12.07 with the lights and stereo and other stuff on (also at both the batt and alt)

 

Sounds like regulator to me...
The batt should be 12.6V sitting on a shelf.
The alt should carry 13.2V on a fully charged batt after you replace the starting drain. Minimum !