Car trouble, can anyone help?

[Heliobas Disciple]

My car has died (wouldn't start) three times this month. The first time, I had the battery checked and the alternator checked my a local mechanic. He said the battery had a bad cell and the alternator was fine (no lights were going off inside the car to alert to an alternator problem either). He said I may get by with the battery in the hot weather, but when it turned colder I'd definitely need a new one. The battery died again later that week and I replaced it at Walmart.

Two weeks later (today) the car was dead again. By dead I mean no noise whatsoever when I turn the key. After jumping it, I took it back to the first mechanic who checked the new battery and said that it looked like a low charge and that the battery was crap (not his exact words ) and that I should never buy a battery at Walmart. He tried to sell me his again for three times as much as I paid at Walmart. He didn't recheck the alternator. Interestingly (to me) was that the new battery checked at the same voltage the original one checked at (in the 10 range).

When I went to Walmart to exchange the battery, it tested fine and the guy there told me my alternator wasn't making the voltage go up, so it could be an alternator problem. But couldn't check it there. If not that, a short somewhere.

I know little about cars, but wouldn't my alternator be working if the battery had more of a charge after a 20 minute drive than before it? If the alternator wasn't working wouldn't my battery been further drained, not recharged? And it started up a few more times this evening without a problem.

Also, the guy at Walmart intimated that if it was a short it would be very expensive to diagnose/find the short. The car is 17 years old and I can't afford an expensive fix on it. Anyone have any ideas/tips/hints????

Thanks, HD

 

[Hamilton Felix]

Hmm.... let's see if we can come up with some simple tests here. Hey, HD, do you have any tools, a test meter?

Drive around with battery fine. Park and unhook a battery cable. Next day, see if it will start after you reconnect the battery. I'm just thinking there's a high resistance short or other internal load that's draining the battery while it sits.

Usually, Checker/Kragen/Schuck's stores will do free battery and alternator tests.

I've found that a battery at Wal Mart for the same price as a battery at Costco will turn out to be "less" battery. But it worked.

Sometimes an alternator can blow a diode, and still charge but only a little bit. Hard to diagnose without a volt meter. I'd expect to see around 14 volts or more, right after you start up. I'd expect 12 volts if I checked it first thing in the morning and the engine had not been started. I believe 13.8 is considered normal when running.

A standard starting battery for a car will lose capacity each time it is run down. Run the battery flat a few times, and it's probably junk. An RV/marine deep cycle battery will stand that sort of thing.

Oh, I forgot to ask if this is a new car that will be affected by unhooking the battery. I sort of live in the past, so I don't expect anything other than having to reset the car clock after I pull a battery. I tend to look at unhooking the battery as a way to reset some onboard trouble indications.

 

[WFK]

The car is 17 years old

probably the alternator is 17 years old also.
The way that thingie works is by magnetizing a rotating electro magnet.
Power to the rotor is supplied through brushes to slip rings.
When the brushes wear out (17 years!!!) no more DC to the rotor, no more AC to the rectifier bank, no more charge to the battery.

First guess is the alternator!

One hint is that the replacement battery tested good in a tester.
That is where they first see if the battery accepts a charge, charge it a bit and load it down. Yes, the no-charge light should have come on, but then it could be gone too.

Item 1, charge battery with an external charger (don't bother taking it out) to see if it goes (slowly) above 13 volts. Unhook the charger and see where is drifts to. If it drifts below 12 Volts the battery is shot.
It has been SEVERERLY discharged and is on the brink of failure (even a new one.)

Suppose it passes this test and stays above 12 Volts, then:
Start car and observe voltage on battery:
It MUST rise with car idling. Normally a working charge system will run it up to 14 volts or so before the charge regulator cuts back on the current into it. (And, by the way, "current into it" means current going into the rotor through brushes and slip rings.)

To get an idea if this basic charge mechanism works, you should find someone (a shop) with a DC Clip-On Ammeter. These thing can measure DC Amps in wires without opening connections.

That is also the tool to see IF there is a short that drains the battery when all things are supposed to be off. That is NOT an expensive test.
What could be expensive is to track it down if there is one.

With a 17 year old alternator, I would not bother replacing just the brushes, but the entire alternator because I wouldn't trust the bearings to last much longer.
---------------------------

Overall, it looks like poor service at Wallmart (if THEY put the battery in - which isn'r clear from your post.) And the p'd off machanic (in your shop) is now of no help either. I think you have to find a THIRD place to have it properly diagnosed.

(To say the alternator is OK because the light didn't come on is NOT a professional answer <== mechanic #1)

 

[Heliobas Disciple]

Thanks Hamilton Felix and WFK.

I have no tools. It's an old car, and it has no clock - so theoretically I could unhook the battery at night to see what happens. Except I don't know how


WFK, you're right. The alternator, like the car, is 17 years old. The new battery did not test good in the tester right after being jumped - it came up that it needed a new cell. By the time I drove to Walmart, (20 minute drive), the test was done by a voltmeter (I think) and it showed 12 volts, he never tested the cells of the battery. I think he was trying to get rid of me. He was the manager, the two young guys actually switching the battery for me until he came over looked horrified at what he was telling me. (first hint). Walmart did put in the battery 2 weeks ago. And my first mechanic didn't test the alternator by the idiot light, that was me. He used some sort of probing thing to check it out.

This is what happened today. I got up and tried to start the car. It barely got started. I drove it around for 20 minutes and stopped it. I then started it up again and it started just fine. I left the dome light on to see what would happen, it dimmed somewhat when I went to start up (the second time - didn't risk having anything electric on first thing this morning). I then let it sit for the day, not wanting to get stuck anywhere. I just went back out and tried to start it again. This time I started with the dome light on. It was pretty dim when I got in the car and got very dim when I went to turn the car over. Once again, it barely made it, but it started and the dome light became very bright once the car was on. I drove around for about 10 minutes to recharge (I'm hoping) the battery.

So, does the light changing mean the alternator is fine? (I hope so).

I called a third party mechanic - actually one I used before who left my station and one I really trust. He said if I could bring him the car during the week, he would test to see if the battery is being drained by something (the same test you suggested), as well as test the battery itself and the alternator again. He said that if the battery was really low or draining, the alternator would be used to charge the battery when I started the car, and not powering the car per se, and that voltmeter (?) thing the Walmart guy used would not have registered any change from the alternator when I turned on the car. That made me feel better.

He suggested I go back to Walmart and insist they give me a new battery but I may wait to see what his diagnosis is on Monday. Frankly if it's the battery, I want to return it out of the car and buy a new one from him. I don't need this type of hassle if the Wally-world batteries are unreliable.

Now get this - the same day my car died, my microwave died (absolutely dead) and two days ago my vacuum cleaner just up and died too. All three have no power. Isn't that strange (not to change this to an unex/alt type thread of course!)? I wonder if it's me....maybe it's time for a tin foil hat or something

Thanks again, and any other hints would be greatly appreciated,
HD

 

[intothatgoodnight]

Sounds like a bad diode pack in the alternator, to me. Unhook the battery at night, and reconnect in the morning -- if car starts right up, then it is likely that the alternator will need rebuilding or replacing.

Could also be some weird short that occurs only when the key is in the off position -- had an ignition switch in an old Chevy do this to me. Replaced defective ignition switch, and problem was resolved


intothegoodnight

 

[Dennis Olson]

Yeah, I'd put an alternator in it. ASAP.

 

[Heliobas Disciple]

The car is dead again. It was dead yesterday when I went out to start it for work. And my work schedule today prevented me from dealing with it, tomorrow too.

Hopefully I can get some time Wedn. to get it jumped and over to Walmart to replace the battery, so I can drive it to my mechanic and let him keep it a few days to see if he can figure out the problem.

Thanks for all the suggestions. This place is great

As soon as I get it checked by a mechanic I'll post what it turned out to be.

HD

 

[WFK]

When things electrical around you die, you have bad Karma

I fixed my son's truck not long ago that had a "battery" problem.
Don't ask make or age, but it is a seasoned contractor's truck. Battery was totally out of acid (at least not visible).

Now that truck has a Voltage regulator at the upper end of the firewall and a battery ground connection (close to the battery) to the chassis. And THAT ground connection was corroded. Battery went through weird voltage swings after it was refilled with destilled water. (And it checked out GOOD at the battery place.)

After cleaning the ground connection the weird voltage swings disappeared and the truck has been running OK with the same alternator and the same battery.

It is unlikely that you have this situation because the battery guys must have checked the acid level and your signs point to under-charge, not overcharge.

The dome light variations you describe are typical for a low battery that ACCEPTS charge from the alternator. But that is all one can say. There can still be defects or discharge into something that SHOULD be off but isn't.

A simple multimeter (with an 10A range) can be used to see if you have a mystery load discharging the battery.

Pull the keys from the ignition, and close the doors (so that internal lights are off). Disconnect one battery terminal (I would pull the Plus) and connect the Ammeter + to battery plus and the Ammeter - to the drifting terminal; use the 10 A range.

If there is no current, there is no drain. Open a car door and see if the internal lights cause a visible current on the meter. If not, it's on the wrong scale. Do NOT start the car with the meter in, or you can kiss it good bye.

The clock can draw some very low current. If you see 1 Amp or more, start pulling fuses until it goes to zero.
That process would isolate the drain.

A meter as required for this test was available recently for $3.99 (battery included!) from Harbor Freight. Probably back to 7.95 or so by now. (Quality Chinese stuff)

 

[Heliobas Disciple]

WFK: When things electrical around you die, you have bad Karma

uh - oh. And I spoke to my mother whose up in NY yesterday, she went outside and found a dead battery in her car (for no apparent reason either). Must be a family karma thing

Here's an update, with a question.

We had some time today, so we jumped the car. I had left the keys in the ignition while we set up the jump with the door open. As soon as the connection with the other battery was made - the buzzer letting me know I had the door open with the key in it went off. Loud and clear. I checked the dome light and it came on. (the car was totally dead two seconds earlier). We still hadn't jumped the car.

Does that mean anything?

Next I drove to Walmart and got a new battery. We unscrewed the trunk battery for the night, since that could be a logical drain we could never see. But I'm not sure about doing that. Does anyone know if there's any danger in unscrewing the bulb and leaving the socket exposed? Will it stop drawing energy if the bulb is out? Should I put it back in?

The car goes to the mechanic tomorrow to see if the alternator is on the fritz (I'm starting to doubt this) or if there's a short somewhere (I dread this but luckily my mechanic is well versed on how to discover this) or if somewhow the connection from the alternator to the battery has gone bad (might not be that expensive to fix) or if indeed Walmart just sold me a bad battery (my hope - since that one has the no cost connected to it!)

HD

 

[DARKSTAR]

Every thing should come on, warning chime and dome light, if the doors were open. No danger of unhooking bulb, with bulb removed circuit is open and no current flow. Put it back in before it goes to the mechanic, or tell him it is out in case no current drain shows up during test. Another bulb to pull if there is one, is the glove box light. Have seen to much paper and junk build up hold door open to not let the switch work.

 

[Heliobas Disciple]

UPDATE

I finally got to the mechanic today.

I got the new battery put in on Wednesday. Besides unhooking the trunk light, I realized the front of the car cd player wasn't on right, so I took that off and put it on. It's a security device which you can bring in the house with you when you park the car, and when it's off, a red light blinks. Anyway, I never mess with it, but someone else in the car had, and I put it back on correctly. The car started great for the next few days, which got me thinking about the radio.

Meanwhile, my mechanic said both the battery and the alternator test fine. It was a pretty extensive test - he had us turn the lights on, the brights on, run the fan, etc. and he had some machine hooked up to the battery the whole time.

Then he checked for a drain on the battery. The meter read a 6 (the lowest on the scale), but it shouldn't read anything at all. I took off the front of the radio/cd player and it went up to 12. I put it back on, and it shifted between 6 and 12. An intermittent drain is what it looks like.

I'm going to go back to where they installed my radio (a year or two ago) and have them pull it out and check the wiring. I'm hoping they can also do a drain test- and do it with the radio out - but realize that's a long shot. I may just have them leave it out, go back to my mechanic and see if there's still a drain without the radio, and then put it back in if that's not the cause.

Luckily my mechanic could recommend a place to go that specializes in electrical problems. It's a mechanic's mechanic, as he put it. All the car dealerships in town use it too when they have an electrical problem they can't diagnose. That will be my next step. He also said that he thinks this place only charges a flat fee to diagnose a drain, not by the hour which all the local mechanics do. That's a relief as well since I hear it can take a while to find these things. Did I mention I have a great mechanic

Anyway, just wanted to thank everyone for the input and update anyone who was reading the thread.

HD