Help! Is this just a dead alternator?

[DirtyMech]

Hello all. My apologies in advance, I know people here like to have all their information

on the first post, but I was trying to get out of town and my car is effectively dead now.

I'm diagnosing the problem in realtime and any help or knowledge from past experiences

you could offer would be very much appreciated. It may be that I already have the proper

diagnosis and would just like to get confirmation. I am mechanically knowledgable.

 

I've got a '95 Subaru Legacy EJ22 Wagon. My batter died due to a suspected dead alternator.

The following things happened prior to the battery dying, while I was driving. At startup:

 

- The engine was making a faint wheezing noise at low RPMs.

- The temperature gauge was running slightly lower than normal.

 

Shortly thereafter these things happened:

 

-The speedometer completely gave out completely.

- The tachometer started giving wild readings.

- The trip and odo meters stopped working.

- My radio started cutting out.

- The battery started dying.

 

Fortunately I was able to recognize the symptoms and park the wagon outside

of my house before turning off the engine and losing starting-capable voltage.

 

I've checked the battery voltage and it's 12.1 Haven't gotten a chance to check voltage

while running the car but I am charging the battery now and will test it very shortly.

 

I know this is a texbook dead alternator. I checked the label and its a remanufactured Hitachi from 1997.

Big suprise, I know. The thing I'm amazed about is all the symptoms. Would the speedometer, odo, trip,

and tachometer all be caused by a bad alternator? If so then it must be a very digital instrument cluster!

I'm also curious to know because I am planning to drive my car to the closest place with an alternator

in stock and want to make sure there are no other problems going on.

 

 

Much thanks!

Edited August 12, 2011 by DirtyMech

[DirtyMech]

Got it charged enough to test.

 

Sitting Voltage: 12.55

Running Voltage: 12.61

 

 

Looks like the alternator. Put it back in the charger.

 

Current Charging Voltage: 12.71

 

Looking for a local supplier now.

[Olnick]

Sounds like you're on the right track, hope replacing the alt does it for you.

 

Are there any "auto electric" shops near you--places that rebuild alternators & starters? There's usually one in an area that local mechanics respect and use. Might be worth calling around and asking some shop guys.

 

Good luck.

[1-3-2-4]

wow that same stuff happened to my 95 Legacy but it was still giving me 14V on the output but I'm going to guess one of the diodes were failing inside.

 

also the cluster the speedo, tach and odo and trip are all electronic driven

[eulogious]

AC ripple will cause some very weird things to happen to any electronics that are in the car and ac ripple is introduced. So yes, having all those things act strange is "normal" for a failing alt.

 

I would also replace the battery, if it's more than a few years old. Sometimes a worn out battery is what causes the alt to fail. Replace the alt and not the batt, and then a few months down the line the new alt fails. Even after charging the battery after this happened. Any sort of overcharge on normal car batteries greatly decreases it's lifespan and usefulness. So after all the weird stuff you have been having I would replace the battery, if you haven't already.

 

Good luck with the repairs!

[DirtyMech]

Oh yeah, success! Got the car running and made it to my destination last night. All my symptoms were caused by the alternator. The engine noise was the faulty alternator bearing or shaft components grinding. All the other electrical problems were solved by the replacement of the alternator. Set me back four hours but I got it all fixed without using a tow truck or bumming a jump from someone.

 

There was an awesome mobile mechanic named Kim parked in the corner of the O'reilly lot in Oakland. He helped me out with a couple tools I forgot at the house after I had charged my battery and driven without shutting the engine off until I got to the parts store. It was my best parts store experience ever because none of the employees minded that A) I was working in the parking lot on my broken down car, and a mobile mechanic was parked in the corner just helping people out who needed assistance. Wish every auto store had that kind of attitude and a helpful guy like that in their parking lot!