carey83gsl

yes, another problem in what is becoming quite the list with this toy of mine. this is a big long and involved, but maybe that will help those interested in helping me find a solution?

my voltmeter has been pretty twitchy, so i just figured that i may as well have my alternator tested for free. it failed catastrophically.

so i got a new one. great! first day, reads @ about 14 volts consistently, obv. dipping a bit with lights etc., on. but all is well.

however, volt meter started getting twitchy again the next day. so i checked the battery charge with the car on with a multi-meter thingy, and it said that the battery was charging @ 14.5 volts, whereas the volt meter in the car said 13.5. So, I figured the new alt. was just fine and was going to ignore the voltmeter in the car from now on.

so, i shift into reverse, and begin to back out of my driveway when all of a sudden ALL the warning lights come on in the car, and the voltage drops to twelve. a quick test reveals that the alternator is not charging the battery, and that the car is running solely from the battery.

so i took this new alternator back to schucks to have it tested. it passed fine. so, i went back and put it back in, and it still doesn't work.

when i quickly rev the engine, all the lights go out and the voltmeter registers. as soon as i let off the throttle, the idiot lights come back on, volt meter drops. and if i rev slowly, nothing at all happens. the alternator begins to work ONLY when the engine is at some specific angle from quick revving, it seems.

so, i figured it must just be a cable somewhere that's shorting out and touching metal, and is pulled away from the metal when the engine is tilted. but i'm having no such luck finding anything like that. every cable / connector looks fine, the strut tower ground / starter connections are all fine, etc.

however, the alternator DID fail a test in the FSM where you check the voltage from the "L" terminal to a ground with the ignition switch on. it says it COULD be faulty wiring, but it's most likely an alternator. but it passed the schucks test fine.

i'll probably get the alt. tested tomorrow at a few different shops. anyone have any ideas?

thanks in advance!

brandon davis

iTrader: (3)

My volvo is doing the same thing. well a family members volvo. im not sure how to fix it either.

carey83gsl

any ideas? i've checked around for wiring in the engine bay about five times, but if i don't come up with something, i'll just have to have it towed to a shop.

bliffle

Classic alternator failure symptoms.

Alternator rebuilds are subject to early failure. I assume you got a rebuild and not really new alt.

Take it to a Chucks competitor.

Jeff20B

iTrader: (13)

Swap it for another reman. After the 3rd or 4th one you'll get a decent one. Reman starters are the same way.

DivinDriver

iTrader: (15)

Oh; thread title made me think someone was giving away free alternators...

Now, I am depressed.

bliffle

It helps to have your own voltmeter/multimeter so that your readings are repeatable. You can get good ones for about $20 at Radio Shack, Home Depot, etc. A harborfreight thay are half that price. I saw a D'arsonval voltmeter at the autostore for $5.

Sometimes, when it's hard to figure things out with just a voltmeter and an ohmmeter, it helps to have a proper ammeter. These have a loop that goes around a cable (like the battery cable, generator cable, starter cable, etc.) and reads out the amps flowing in the wire. Very nice! You can tell how many amps your starter uses, how many amps your generator supplies, etc.Improves the simple picture you get from a voltmeter, sometimes. I haven't gotten one yet because I've been using voltmeters so long I can usually figure things out with just that. But most of all I'm just cheap (like the typical FB guy).

carey83gsl

alrighty, well i've had the alternator checked by a reputable auto electrics shop, and he says its fine. so, rather than continue to search for problems that i can't find, i'm going to take the car in to them and have them diagnose it for me.

i'll let you all know what it is.

i've checked all the connections and whatnot, replaced the positive battery cable, checked current through the negative cable all the way to each ground, had the alternator checked about 4 times, and checked the fuses about 4 times as well.

grrr. i hate not being able to figure this stuff out by myself. of course, the only electrics i dealt with on my old datsun were the battery and heater fan, so any real electrical problems are pretty new to me.

carey83gsl

*sigh* it WAS the alternator.

after further tests, the alternator voltage would drop off at anything resembling idle RPM. like..it would pretty much shut off. and neither Schucks nor the place i brought it to test alternators at lower RPMs. which is stupid.

so anywho. they've given me another one, which was free under warranty, and we'll see how this one goes. however, i've noticed that this new one they gave me had a piece on the back that the one that was bad DIDN'T have...

so. history of schucks alternators so far:

#1: huge crack in the side. wouldn't turn. luckily, i noticed immediately and got another one.
#2: problem cropped up only at idle RPMs, wouldn't show up on tests. and it was missing a piece.
#3: ???

oh well. hopefully this one works.

bliffle

So, Jeff was right!

The question remaining is: how did the shop determine the problem? Voltmeter? Ammeter? Substitution test?

carey83gsl

haha yeah, as usual, you guys were right. and the schucks guys were wrong.

i didn't specifically ask him, but he said he checked the voltage to the battery with the car idling, and also checked the voltage using something else that eliminated the wiring in my car, and it was still putting out squat.

he seemed pretty darn knowledgeable. he guessed the car from the alternator, which is pretty impressive..

AND he said he's never seen this problem before (fine output @ high rpms, no output at low rpms), and that a replacement would probably fix the problem. we'll see!

RotorMotorDriver

iTrader: (1)

As someone mentioned, I once went through 4 before getting one that worked. I would just argue with them when it passed their bench test until they gave me a new one. I just started telling them that if it was fine, they could put it back in the box and sell it to someone else, but I wanted another one because it didnt work in my car.

Luckily our cars are easy to get them in and out of, not like some of the Hondas Ive worked on at work where you have to unbolt the motor mount to get the belts off, lift the engine to get the alt out, etc...

Anyway, glad you found the problem. Another word of advice I would throw out there for anyone reading is to make sure your battery is fully charged and in good condition with a new alternator. If its low or dead from running with the bad alternator, you can fry the voltage regulator when its trying to recover your dead battery, thus killing it.

~T.J.

bliffle

Also, check the electrolyte in the cells. get that $4 cheapo hydrometer with 4 floating *****. If the fluid is low add distilled water. I once had to add a quart of water to a battery.

What happens is that no one ever checks the fluid in the battery so it tends to dry out until after 10 years it doesn't hold a charge and the car won't start and the owner goes to the garage and they tell him he needs a new battery ($150) and $100 to put it in. All it needed was distilled water and a trickle charge. The mechanic takes the 'dead' battery home. adds water, and puts it into his RV solar battery array and gets another 20 tears of service out of it.

carey83gsl

alright, well, this one was bad too.

or, my battery was low and fried it from the sounds of it...BUT, my battery still starts fine, and powers everything fine. hm.

i AM going to check some wiring around the power antennae and see if there's anything loose back there, it was pretty messed up last time i looked. but i still don't really see how that could cause this problem. but who knows!

bliffle

Do what Jeff says.

carey83gsl

alrighty, i'll take it back again. at least the people at this schucks are pretty nice.

and at least it was cheap.

carey83gsl

oh, also, my temp gauge goes up quite a bit when it's running on the battery, but when the alternator charges (under acceleration), the temp drops back down. i guess i'll chock that up to the alt problem.

again, i'm going to check the rear wiring before getting a new alternator, but has anyone else experienced a wiring problem that shorts out alternators? is this even a possibility with the symptoms i'm having?

thanks!

bliffle

Why do you suspect the rear wiring? Are the wires hot?

Temp gauge variations may be bad ground. Check grounds with your voltmeter.

carey83gsl

well, i don't know. i guess i suspect it because i'm frustrated and running out of ideas, and the wiring is so messed up back there. there's ones cut and spliced together here and there, it's weird.

i've checked the driver's strut tower ground as well as the ground down near the transmission, and they're fine. are there any crucial ones i've missed?

carey83gsl

problem solved!

it wasn't the alternator.

lesson learned: a multi-meter is no substitute for taking off grounds and cleaning them yourself. the ground down by the transmission was pretty grimy. that seems to be the cause of it.

however, in the process of all of this, my temperature gauge has decided that my car is overheating all the time now. hoorah. search time!

bliffle

You have to have the voltmeter across the suspected ground while you're cranking the engine.

orion84gsl

iTrader: (5)

My temp gauge just started doing that as well. Turns out the temperature sensor isn't functioning properly. The thermostat is actually opening when the temp gauge says its nearly over heated, but it will sit there and not budge, but it's actually at perfectly normal temps. Also no water boiling into or out of the overflow bottle. Had me stumped. I replaced my thermostat, but that didn't make the problem go away, but after some checking my buddy and I came to the conclusion the gauge wasn't reading correctly.

Also my alternator is giving me some problems too. Lights are dimming voltage is sitting at 12 and has actually dropped below that. Going to have to read up on this one.

bliffle

Do you have an OEM tstat? Is it installed with the jiggle stick up? Did you take it out and test it in the stove in a pot of water?

Did you clean off your battery posts and cable clamps with that $4 ID/OD wirebrush from the autostore? You DO have one, con't you?

Did you verify the battery voltage with an independent voltmeter?

carey83gsl

yeah, my temp gauge immediately shoots all the way to "H" even when i've just started the car, so i know that the car is (presumably) operating at the same normal temps it always has. definitely something that needs to be fixed in the near future though. i'll check the sensor. there IS a cable that i fiddled with right below the beehive cooler, is that it?

orion84gsl

iTrader: (5)

-I did, but it's been replaced with a new one from NAPA, and yes it is in correctly. I will test the old one on the stove soon.

-Battery cables were just replaced. Cleaned the terminals on the battery and on the starter. Used dielectric grease on all connections. And no I don't have one of those, but my bigass wire brush works just fine.

-...nope. Not yet anyway. I'll have to do that tomorrow when I'm helping Sam with his car. I don't have a proper voltmeter and I've spent more than enough money this week, so I'll have to use his.