Is my alt going?

[1-3-2-4]

Im here just got to maryland and my car starts to go nuts my tach dropped to zero and radio cut off and back on. With no headlights on it seemed to do better. Im mobile now with 185 mi to go

[J A Blazer]

Similar problems happened to my 2000 4-cyl OBW in the weeks before my alternator finally died.

[1-3-2-4]

No warning lights or anything like that.. Can I make it back home? Its like 360 miles

[davebugs]

A lot of times you'll get an erroneous ABS light and another seemingly unrelated idiot light(I forget wha tit is).

 

If it dies, and you have a good battery wait an hour, start it up, and head to the nearest battery place. Your distance between when it craps out will keep getting shorter.

 

Often you'll notice there is no high RPM's - almost like a fuel delivery problem. That's really the battery dying since that's what you're really running off of.

[GeneralDisorder]

Stop in at a discount tool shop or hardware store, etc and grab a multi-meter. Check the voltage - should be about 14.5v DC and should NOT increase beyond that with throttle. Then check for AC current off the alt. Should be no more than 0.25v AC (higher indicates rectifier failure). If either of these tests come back higher you risk damage to circuits and devices on the car including the battery.

 

GD

[nipper]

Stop in at a discount tool shop or hardware store, etc and grab a multi-meter. Check the voltage - should be about 14.5v DC and should NOT increase beyond that with throttle. Then check for AC current off the alt. Should be no more than 0.25v AC (higher indicates rectifier failure). If either of these tests come back higher you risk damage to circuits and devices on the car including the battery.

 

GD

 

 

Thats with everything on and reving at 1800 rpm. If it is low, then shut everything off except for lights and wipers. That may get you to bordeline or just a hair below then you can make it home. Stick to well travled roads just in case.

[1-3-2-4]

Yea im jusy running the bare stuff has not done it again so far

[1-3-2-4]

Made it to richmond, va

[Suzam]

Now the diagnosis fun begins!

[edrach]

First educated guess: clean and tighten battery terminals.

[1-3-2-4]

Dont know if I can get it any cleaner

 

*edit on the laptop now

 

I left my meter on the bed I said to myself I don't think I'm going to need this :-/ Something like this happened when leaving work one day.. I tried to make it come back by turning on everything in the car and I never could get it to do it again.

Edited October 4, 2010 by 1-3-2-4

[edrach]

Dont know if I can get it any cleaner

Was either terminal the least bit loose?

 

Reason for my "educated guess" was that you had a momemtary loss of voltage when you turned on the headlights. A poor contact at either battery terminal (or other locations that carry high current), would result in a voltage drop when you called for enough current to turn on the headlights. I'm a firm believer in checking the simple, easy stuff before getting into the difficult causes.

[edrach]

That's really the battery dying since that's what you're really running off of.

Sorry, I have to disagree here. The battery's only purpose in life is to start the engine. Once the engine is started, the alternator supplies ALL the current for the car's normal operation. If the alternator fails to supply the needed current, then the battery takes over again until the battery runs out of charge.

[1-3-2-4]

Was either terminal the least bit loose?

 

Reason for my "educated guess" was that you had a momemtary loss of voltage when you turned on the headlights. A poor contact at either battery terminal (or other locations that carry high current), would result in a voltage drop when you called for enough current to turn on the headlights. I'm a firm believer in checking the simple, easy stuff before getting into the difficult causes.

 

No nothing was loose and my headlights were already on when it was doing what it was doing.. However my ham radio gear transmitting at 45 W pulls about 13 A from the socket.

 

I would of did a video but it was going nuts while the car was at idle it pretty much went like this..

 

foot on brake or rolling or stopped in neutral

 

tach bounces to 0 rpms dash lights flick off then back on, radio also shuts off then comes back on.

 

Never stalled, Since I was tired I stopped to rest for about 3 hours in Elkton, MD started the car up and drove another 180 miles with no other issues.

 

Last time I checked the Alt which was about 4 months ago the output was good but it may be something flaky on it now which only shows up at random times.

 

While I was driving and at idle I turned on my headlights and fogs and it never cut anything else off.

[Fairtax4me]

If the alternator fails to supply the needed current, then the battery takes over again until the battery runs out of charge.

Exactly... once the alternator dies, which is the hypothetical situation he was trying to describe.

 

A lot of times you'll get an erroneous ABS light and another seemingly unrelated idiot light(I forget wha tit is).

Airbag light.

 

It took you 7 hours to get from MD to Richmond, VA? You pushing the car or what man?

[1-3-2-4]

Exactly... once the alternator dies, which is the hypothetical situation he was trying to describe.

 

 

Airbag light.

 

It took you 7 hours to get from MD to Richmond, VA? You pushing the car or what man?

 

lol I was making good time but I would of been super early like almost 24 hours early so I entered in some long rest time

 

the crosswinds were pretty strong gas mileage is around 25.6 MPG and that's with a crappy aliment right now.

[Fairtax4me]

My car did some screwy stuff when the positive post on the battery was about to break off. There was a thread about it, sometime last fall IIRC. It eventually did break, and any sudden use of electricity would kill the car. I limped it to the local advance auto. The trip was all downhill from the grocery store parking lot where I had to roll start the car. Car stalled when I hit the brakes to turn into the parts store lot. I parked and started taking the cables off the battery. The post came off with it.

[Arty]

This sounds exactly like what my car did before the alternator went kaput. The gauges bouncing around was the kiss of death. What ended up being the problem was the lead wire to the alternator from the battery terminal was making contact with itself, shorting out the system. Apparently, a few friends of mine with Subarus have had the same issue. I hope it's this simple for you as well. Though I don't understand why I didn't make it 25 miles and you're making it for hours on end...

 

 

best of luck to you, man.

[davebugs]

Sorry, I have to disagree here. The battery's only purpose in life is to start the engine. Once the engine is started, the alternator supplies ALL the current for the car's normal operation. If the alternator fails to supply the needed current, then the battery takes over again until the battery runs out of charge.

 

Exactly what I meant. If the alternator is gone, the car resorts to the battery until it is exhausted. The thread was asking about bad alternator symptoms.

 

Net effect is what I proposed was happenning to the OP. I just skipped an unneeded(obvious to me atleast) step in the explanation.

 

We're on the same page.

[1-3-2-4]

This sounds exactly like what my car did before the alternator went kaput. The gauges bouncing around was the kiss of death. What ended up being the problem was the lead wire to the alternator from the battery terminal was making contact with itself, shorting out the system. Apparently, a few friends of mine with Subarus have had the same issue. I hope it's this simple for you as well. Though I don't understand why I didn't make it 25 miles and you're making it for hours on end...

 

 

best of luck to you, man.

 

When I stopped at the shell in Elkton, MD and after I woke up I looked at the alt and the output cable it seemed like it was stripped.. I'm not sure what you mean by making contact with it's self.. do you mean the body of the alternator?

[edrach]

We're on the same page.

Yea, I figured that out when I re-read your post. Sorry, didn't mean to be quite so combative.

[edrach]

When I stopped at the shell in Elkton, MD and after I woke up I looked at the alt and the output cable it seemed like it was stripped.. I'm not sure what you mean by making contact with it's self.. do you mean the body of the alternator?

If the wire portion of the alternator's output cable touched the body of the alternator or engine (electrical ground), it will result in pretty immediate loss of voltage (original symptom you described) and possible damage to the alternator itself. Tape any part of the alternator wiring up with vinyl electrical tape NOW if there's any possibility of the bare wiring touching the metal body of the alternator and/or engine. Hopefully, nothing else was damaged.

[1-3-2-4]

Cross your fingers if I can get this picture posted just took it

[1-3-2-4]

I

[idosubaru]

yeah cover that up. when you have time check those alt connections and make sure the plastic plug into the alt isn't brittle, falling apart, corroded. haven't seen it much on EJ's yet, mostly older stuff, as they're not reaching that age yet but give it a check along with that copper cable.

 

crank pulleys are known to separate too. they are made of two completely separate pieces of metal with a very thin rubber ring between them, you can see if you look closely. if the pulley slips, the inner ring turns with the engine but the slipping will make the outer ring not turn as fast...reducing alternator output. draw a line across the face of the pulley. if the line gets "broken" later after some driving, you'll know your pulley is separating. fix it before it falls apart.