# Car Died On The Road... Is It The Alternator?



## milkyspit (Feb 17, 2005)

I need help from some of you auto guys on diagnosing a problem with my wife's car!
/ubbthreads/images/graemlins/help.gif

Last week my wife went out to her car, a 1990 Toyota Camry that's generally been running well, and it wouldn't start. Wouldn't even turn over. The strange thing is that it happened when she was at a local farmer's market getting some stuff... and when she had started the car to GO to the farmer's market maybe half an hour earlier, the engine started just fine!

She called me at work, and I instructed her to get a jump start from someone else in the parking lot. She did, drove home, and the car ran just fine.

When I got home, I measured the battery voltage with my DMM, and it read 12.58V. Then I started the car... started fine... and read the voltage again, with it presumably coming this time from the alternator... it read something around 13.8V. (I don't remember this particular number exactly.) I let the car idle for about 15 minutes, then shut it off and again measured the battery's voltage, which was around 13.02V, so I assumed things were working properly, as it seemed like the battery was slowly recharging as expected.

Today she called me again at work to tell me that the car DIED WHILE SHE WAS DRIVING IT. This is bad!!! She had the good sense to pull to the side of the road immediately, and fortunately for us a local architect came out to assist her. He jump started the car and followed her home to make sure it didn't die again en route. As he was leaving, he suggested that the alternator might be shot, mainly because the battery in the car is only a year old, is a very good battery... and because a bad battery wouldn't have started the car, but then caused it to die in the middle of driving.

I can add the following background information. About a year ago the battery we had in the car at that time "died" and was replaced by my uncle, who's generally an excellent mechanic. At the time he said the car still had its original alternator, but that it seemed to be functioning properly. However, about a year before THAT I replaced the PRIOR battery myself when THAT one had seemingly "died." So we're on our third battery in a 2-3 year span. Something ain't right, and IMHO it's not that we're buying crummy batteries! /ubbthreads/images/graemlins/mad.gif

This brings us to the inevitable questions: what's wrong, what should I replace, and how can I get it done as inexpensively as possible without sacrificing the quality of the repair? I'm guessing alternator for now, but does this history sound like the symptoms typical of a dying alternator? What do I do?

I'm pretty much an automobile engine newbie. If anyone can offer some advice to get me going in the right direction, please do!

/ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif


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## raggie33 (Feb 17, 2005)

start car disconet batt if it dies alternater is bad


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## Topper (Feb 17, 2005)

Raggie is right on top of this give that a try, architects
don't no squat about car batts but he might be right.
Topper


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## gadget_lover (Feb 17, 2005)

If the alternator is bad the battery will keep the car running for quite a while.

The fact that the battery read over 13 volts after driving it indicates that the alternator works at least some of the time.

As raggie said, if you disconnect the battery while the car is running the alternator should keep it running.

The sudden death would indicate a possible bad ground. I'd check where the battery cable grounds to the block as well as where the engine computer is grounded.

Other than that, I'd drive for a bit with a volt meter attached to the cig lighter outlet to see if the voltage is dropping suddenly at some point.

Voltage regulators can also make things interesting. /ubbthreads/images/graemlins/smile.gif

Daniel


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## Moat (Feb 17, 2005)

Alternator brushes will eventually wear out, and can charge intermittently towards the end - which could be your case (they may be replaceable, although often the slip rings and bearings will need attention too). I'd also give a real close look at ALL of the connections/junctions/cable ends (pos and neg) from the battery to chassis ground(s) and starter/fuse box/bus supply/etc. Like maybe check 'em for V drop across junctions while under load. Also might try driving the car with an accurate Voltmeter connected, to monitor any wild swings/drops.

I've always shied away from disconnecting the battery while running, as I've heard transient Voltage spikes can smoke the regulator (or worse)...???

My $0.02, Milky!


Edit - Ooof... Daniel beat me to it!


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## CiTY (Feb 17, 2005)

Alternators and water pumps, I would replace if they were over 100k as a rule of thumb. No need getting stranded...


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## Lurker (Feb 17, 2005)

Intermittent problems of "dead-- won't crank" can also be caused by a corroded battery terminal when the cable-to-terminal connection is weak.


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## dimwatt (Feb 17, 2005)

Milkyspit, Call some of the local auto parts stores. Most will test the battery and/or alternator for free. Stay away from most garages for this test as ineviteably, you battery AND alternator will be "bad"! (maybe your brakes too)

dimwatt


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## dimwatt (Feb 17, 2005)

Milkyspit, Call some of the local auto parts stores. Most will test the battery and/or alternator for free. Stay away from most garages for this test as ineviteably, you battery AND alternator will be "bad"! (maybe your brakes too)

Disconnecting the battery is a positive test but on newer vehicles can cause the alternator to fail, if it hadn't already.

dimwatt


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## Lurker (Feb 17, 2005)

If you disconnect the battery, the car will stall only if the alternator is not currently charging. If your alt is bad, it must be an intermittent problem or your battery would be dead in minutes. Therefore I wouldn't expect the test to work in your case.

Definitely get it checked out with proper diagnostic tools.


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## Zelandeth (Feb 17, 2005)

I had a car which did this a year or so ago. Would be driving fine, then just lose all electrical power without warning. Turned out to be a dodgy earth connection between the battery and the body. 

I'd reccomend against disconnecting the battery with the engine running, given the level of the electronics in cars these days, I'd be seriously worried about frying something (Then again - I'm paranoid) I'd get it checked out by someone with the correct equipment.


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## juancho (Feb 17, 2005)

Milky,the same thing happened to me and it was a faulty negative coonection to the ground of the car, because that cable sneak out under the engine it is difficult to check.
If is that, do as I did and make the negative connection short and *visible* to a top part of the engine near the battery.
Juan C


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## Lynx_Arc (Feb 17, 2005)

I have had similar problems with a car awhile back. It could either be related to starting system or could also be electronic ignition module intermittent failure. The time it took to get jump started may allow it to cool down and be able to work. I had my car die while driving and wouldn't start right away then it got to where it took over an hour to cool off the module till it started. I noticed when I took off a plug wire that any electrical activity at all caused a spark at the plug when the key was in the igniton on position and not started/running.


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## BIGIRON (Feb 17, 2005)

My bet is simple problem with cables or connecters. Just make sure all connections are clean and tight. Don't forget that with age a cable can corrode and fail inside the sheath where it's not visible.

Sounds, from your testing, the alternators ok. I subscribe to the "don't disconnect the batt while engine running (and don't connect jumper cable when engine running) theory. No need to gamble many $$$ electrical parts.


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## greenlight (Feb 17, 2005)

My car died while I was driving. It was definitely the alternator. If you can get to it in the engine compartment, you can change it really easily. Or you might have to pull the engine.


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## Brock (Feb 17, 2005)

My money would be on a bad wire from the alternator or battery to the rest of the system.

I would strongly recommend not disconnecting the battery while the car is running; in newer cars this will damage computers and the like. In older car you will often get rapidly fluctuating voltage that can still cause damage. In really old car (maybe yours) it might be ok. In any case if the voltage rises while idling you have already ruled out the alternator. However it could be regulation of the alternator.

I would get a good voltmeter and see if you can watch it while running the car from the cig plug. Check to see if it sometimes quickly falls off (loose wire or bad regulator in the alt) and comes back up.

Just jumping the car wouldn't get enough power back in the battery for any real length of time, so it must be working sometimes. In any case I would charge the battery overnight to make sure it has a good charge on it, and if it stops again, check the battery voltage at the battery BEFORE jumping while trying to start. If the battery voltage drops really low the battery is shot, if it just sits there it is a bad wire.


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## BlindedByTheLite (Feb 17, 2005)

i just had to replace my alternator a couple months ago. it was going haywire and was draining brand new batteries within a day or two. replaced the alternator and everything's fine now.

also, as a new rule, i do not run ANYTHING in the car, not the radio/heat/lighter/headlights or anything if the engine is not also running. nothing drained the battery faster during my alternator problems than running something in the car with the engine off.


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## Minjin (Feb 17, 2005)

Testing the alternator without load is pointless. Go out with your multimeter and try again. This time watch the voltage and gradually turn on your lights, blower motor, radio, and rear defroster. Now you're actually testing the alternator. Engine might drop 50 rpms or so and voltage will go down, but it shouldn't sag below 13.5v or so.

If the alternator really did go bad, and she drove it till it shut off, the battery is probably shot. You should be able to test it and it might show 11 volts or something. Test it with load and it should be under 9 volts. Also, you didn't mention the incredibly obvious. If the alternator went bad, her battery light would have come on long before the car shut off. You can generally notice as things start shutting down as well. Many radios will turn off as voltage gets lower. The blower motor will get slower. These are all details that people should be noticing when they drive cars. For most people a car is the most complex machine they will ever own, yet they have no desire to learn anything about or observe the behavior of their own car. 

It always amazed me when I worked as a mechanic how oblivious people are to problems. No, the car shouldn't be shuddering when you're accelerating from a stop. No, you shouldn't hear loud bangs every time you hit a bump or small pothole. No, you shouldn't have to turn the steering wheel half a turn before the car moves in that direction...

Mark


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## markdi (Feb 17, 2005)

do not forget about the ground connection to the frame or block of the engine - it could be bad - intermittant


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## DarkLight (Feb 18, 2005)

Dunno but when I replace my batteries and alternators I try to up the ratings as much as possible within reason....

I say check ground then have car diagnostics run..

computer controlled cars can be quite tricky..


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## eluminator (Feb 18, 2005)

I would suspect the battery cable connections. I would remove them from the battery and clean them up and re-attach them snugly. If your cables attach to the posts on top of the battery, you can get a special wire brush to clean the posts and the cable connections. You should see shiny lead on the surface when they are clean.

And don't forget the other end of the cables. The ground (black) one is simple. It probably bolts to the engine.

The connection of the wires to the battery can fool you. They can seem good to the casual observer when they aren't good. When you start the engine 100 or more amps goes through these connections. This will do strange things to the surfaces of the lead unless the resistance is very low.


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## Lurker (Feb 18, 2005)

One final thing to consider. I think you said this is a 1990 vehicle. That makes it about 15 years old and based on its age, it may have well over 200,000 miles on it by now. Even if the mileage is considerably lower than that, it's age is still a problem. In any case, this car is most likely on its last legs and you might want to think about replacing it at some point. Do you want to spend money on repairs at this point or is it time to give up and apply that money to a newer car? The cost of an alternator replacement could be in excess of the market value of the vehicle.


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## Wingerr (Feb 18, 2005)

My bet is on an intermittent battery cable connection- I'd go with the load test Minjin outlined, checking voltage at the terminals as well as the battery posts. Don't bother removing it for an offline test. 13.5 volts while running indicates the alternator is fine. Intermittent problems are hard to pinpoint sometimes, so you'll have to try to induce the failure with jiggling or extended running to heat things up.
The no-start being characterized by symptoms of no cranking action indicates a simple power loss, not anything to do with ignition modules, fuel systems, etc.
If you lose the battery connection while driving, it can very well stall out even if the alternator is okay, if you introduce a sudden load like applying the brakes. It may result in the voltage dipping below the requirements for the ignition and injectors, and stall out before the alternator can compensate. Not advisable to disconnect while running, for the reasons stated before.
Check the cable connections on the other end (not just the battery end), because they're often neglected until problems crop up. Remove them, wire brush them, and generally clean them up before reinstalling.
A 1990 car is still new in my view- /ubbthreads/images/graemlins/smile.gif My 1993 Saab is my "new" car right now!


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## markdi (Feb 18, 2005)

most cars when the alt is good and the engine is running have around 14.5 volts at the battery.

my 88 grand am never causes me any electrical or computer problems.

but I have cleaned the main ground to the engine.
and the electrical connectors have silicon boot/seals

oh and get this

the battery connectors on my old car are side post and they have seals on them(factory stock- original-never replaced)

no part of the connection between the connector on the car to the terminal on the battery is exposed.

my battery terminals/connectors(on the car or battery) have never needed to be cleaned - ever

I have owned it since 92.

why all cars are not this way is a mystery to me.

they did a lot of things right on my old car.

every thing on it works and works well.


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## Wingerr (Feb 18, 2005)

But unless he's going to trade up to an 88 Grand Am, he has to find out what's going on with his car-
How long do you go between battery replacements when running at a constant 14.5V, assuming it's not still on the original battery? If you measure it when it's cold, right after startup, the voltage is higher, but afterwards, I would consider 14.5 to be a bit on the high side. So long as you have no problems, I guess.


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## markdi (Feb 18, 2005)

my mom's 97 mini van and my old ford curier truck
both charge at more than 14 volts

my other grand am with the std quad four charges at the same voltage as the one with the w41 ho quad four.

batterys last me between 5 to 7 years.

I think this is the second battery I have bought for my 88.

I had a mazda that would blow the diodes in its alternator one at a time. dc voltage would go down and ac noise would go up-- I could hear it in the radio.


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## Saaby (Feb 19, 2005)

[ QUOTE ]
A 1990 car is still new in my view- My 1993 Saab is my "new" car right now! 

[/ QUOTE ] /ubbthreads/images/graemlins/grinser2.gif

Anyway, here's an excellent article to read before you decide it's time to buy a new car. Even if you don't agree with the article there's some good, solid advice in there.


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## markdi (Feb 19, 2005)

I would love to have a newer car.

I am not in love with grand am's or quad four's.

I just keep fixing it every time it blows a head gasket

about every 80 to 90,000 miles or so.
I take the whole engine out of the car and replace every 
gasket on the engine and clean and inspect every thing.

74,000 miles or so to go till this head gasket pops.

I bet the head gasket would last longer if I drove slower and did not punch it all the time.

and I bet my car is one of the uglyest owned by a cpf 
member.

needs a paint job bad.

a good honda car would probably last me the rest of my life.


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## SilverFox (Feb 19, 2005)

Hello Lurker,

My wife and I were amused by your comments...

Ryan, thanks for posting a link to that article. It makes sense to our family.

We just dumped about $1000.00 into our older Volvo. Older Volvo's do not have much meat on the disk brake rotors, and every 10-12 years you have to replace them.

Overall, we have spent close to $12000.00 on repairs on this car. It is probably time for a new one. The body is crap, but it runs very well. 

Oh, did I mention that I bought it brand new in March of 1971? It has 330000 miles on it. Next month it will be 35 years old.

My other vehicle is a 1953 GMC... and my son drives a 1963 Caddilac...

Love the classics.

Tom


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## Draco_Americanus (Feb 19, 2005)

[ QUOTE ]
*Lurker said:*
One final thing to consider. I think you said this is a 1990 vehicle. That makes it about 15 years old and based on its age, it may have well over 200,000 miles on it by now. Even if the mileage is considerably lower than that, it's age is still a problem. In any case, this car is most likely on its last legs and you might want to think about replacing it at some point. Do you want to spend money on repairs at this point or is it time to give up and apply that money to a newer car? The cost of an alternator replacement could be in excess of the market value of the vehicle. 

[/ QUOTE ]

I persoanly do not use the market value of a vehical based on what I will spend on repairs, for Me it's the overall history the vehical has had while I owned it and the condition of the vehicle. I also assume by the time I am done with a vehical it's scrap! You should see My s-10, most would have scraped it 10 years ago, but if 100 bucks will keep it running another few months, thats better then a car payment!
Anyway by reading the posts I too sugjest checking the ground cable.


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## Draco_Americanus (Feb 19, 2005)

[ QUOTE ]
*Minjin said:*
For most people a car is the most complex machine they will ever own, yet they have no desire to learn anything about or observe the behavior of their own car. 

It always amazed me when I worked as a mechanic how oblivious people are to problems. No, the car shouldn't be shuddering when you're accelerating from a stop. No, you shouldn't hear loud bangs every time you hit a bump or small pothole. No, you shouldn't have to turn the steering wheel half a turn before the car moves in that direction...

Mark 

[/ QUOTE ]

This is too true, but I will also say that there are certian things one may not realy notice, I try to be as absrvent as posible but I failed to notice the gross play in my Jeep's steering wheel untill after I drove another vehical, I promptly got that fixed. 
As for an alternator failing under load, I had that happen with my one older buick, the lights dimmed, the radio made a "putt putt sound" I then learned to not get cheap replacemnt parts, I built a voltage monitor and pluged it into the cigerette and watched the voltage very up and down with just the turn signal on.


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## Samoan (Feb 21, 2005)

get your relays switches and sensors checked as well. There are plenty of relays and sensors that are designed to kill your engine if they pick up a bad signal.

I was haivng very similar issues with my ZJ a couple months ago and a new ESO relay fixed everything.

-F

-F


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