BATTERY OR ALTERNATOR?

Buffalo Surfer · Post by **Buffalo Surfer** » 13 Aug 2011, 12:47

Hello Everyone, does anyone know the symptoms of a bad alternator? My battery I was told is good(By Walmart) but it lacks strength when I try starting up the car, sometimes no turn whatsoever and others it starts right up. If I let it sit when it doesn't turn it will crank after a while and barely start. I check the fluids and the level is is ok in the battery......any clues to my problem?

Post by **Pauloil** » 13 Aug 2011, 14:56

frustrating problem, I'm sure. starting probs should start with checking the wires first. You will need DVM. (digital volt meter.) i buy mine at harbor freight for $4. search for drop voltage and alternator under this chat room and read up. to answer your question we need to know what your cables are like first. then what the voltage is at batt when car is running. etc.

Post by **Ozark Lee** » 13 Aug 2011, 15:28

Is your battery light lit on the instrument cluster? If so I would suspect the alternator. If not I would suspect the battery.

A complete alternator failure will light up the battery light. The alternator can get weak and not light the light but that is not a normal failure mode. The battery or the cables are also suspect as was pointed out before.

...Lee

855 moneypit · Post by **855 moneypit** » 14 Aug 2011, 21:12

How is the wiring? Everything buttoned up nice and tight? Check for a loose nut on the starter as well. Went through 3 starters when the issue was the nut backing off causing intermittent starting problems.

Post by **Pauloil** » 14 Aug 2011, 21:25

lock washers are nice!

Volvos rock3 · Post by **Volvos rock3** » 15 Aug 2011, 09:06

I would definately suspect a loose/bad connection/wire with an intermittant problem and no idiot lights.

Billc1015 · Post by **Billc1015** » 15 Aug 2011, 16:01

Your starting issue is not being caused by the alternator if your battery is testing good. You should check the positive wire going from the battery to the starter. It sounds like you may have too much voltage drop in that wire.

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Chris Bowsman · Post by **Chris Bowsman** » 15 Aug 2011, 18:19

I work in an auto parts store and test a bazillion batteries/starters/alternators every day. Before you do anything else, go outside, clean up your battery terminals and make sure all the charging system wire connections are tight. Most of the people coming into my work with problems have batteries that look like a science experiment is growing on the positive terminal.

Post by **JRL** » 15 Aug 2011, 18:35

Your positive cable may be totally shot
If so the battery will not take a charge

Chris Bowsman · Post by **Chris Bowsman** » 15 Aug 2011, 20:20

JRL wrote:Your positive cable may be totally shot
If so the battery will not take a charge

We have people who buy batteries or alternators frequently coming in, claiming they're defective. We test them, they're fine. They argue, we give them a new one. Repeat several times. Once we can convince them to try replacing the battery cables, we never see them again.