Alright, here's the deal. I'm working on my brother's car. He has a 1993 Subaru Legacy Wagon. The thing is throwing me a curveball as far as the power output goes...lets explore, shall we?

A while back, he was having problems with the alternator putting out irregular voltage....so we decided it would be a good idea to replace it. At the same time, we just decided to drop a new battery in there too for good measure and/or ****s and giggles. Well over the course of the past few days, we've noticed a fun little situation. Irregular voltage again. The lights would dim, then brighten. The wipers would slow down, then regain speed. The windows were slow then fast, and the blower motor would jump to alternate speeds at its own accord. So from about a week ago, its just been a smorghasbord of ups, downs, and the remote desire to inject a couple CC's of arsenic into my temples. Whether or not someone out there has the true answer to this problem, input is greatly appreciated. Thanks guys (and girls).

 

Id check all the connections at the battery and fuse box.

 

It sounds like a voltage regulation problem. I'm not sure what controls that, but this is a most unusual problem. Maybe post this over on the Legacy Central BBS too ( http://bbs.legacycentral.org )

 

There isn't any auxilary stuff hooked like an amp or anything is there? Did you check the belt? I know it sounds obvious, but that is one weird problem. Oh and the regulator is in the alt. Maybe a bad rebuild.

 

sounds to me like one of your wires is starting to ground out and its stealing your power and soon it will just take all of it once it welds itself off somewhere. It might take you a while but i would check all of your wire but mostly just your main power wires make sure they have full insolation on them still and if you see any cracks or **** like that near anything that it could jump some current then i would change that wire. Even if you find one though i would still go ahead and look through the others just to be safe too though.

 

Does all this stuff happen at the same time? If so, I would say that it was the belt tensioner. If not, then its part pf the actual voltage regulation system, I would take it a local mechanic and have them run diagnostics on it, I know its a 93, but someone somewhere should have the right adapter for the diagnostic machine to plug in. and on another note, I had 95 Mx6 that was doing the same things as your brothers car, and it was the temperture sensor in the mass air flow sensor that went bad, the only way I figured it out was my car was running extremely rich, smell the exhaust. The mass air flow sensor, controls the amount of air being sucked into the engine, when the temperture sensor falls, the computer thinks the air is either to cold or too hot so it tries to compensate for the lack there of by mixing more fuel into the combustion chamber, all this in turn causes rpms to fluctuate up and down.

 

Are you sure it isn't haunted ?

To me it sound like a possibly corroded ground terminal, although many of the suggestions here make a lot of sense too.