1990 Legacy Battery Issues

[jjesien]

Hi there,

 

So I just bought a high mileage 1990 subaru legacy with the 2.2l and auto trans. I went into it knowing there were some issues to resolve, those being primarily leaking valve covers and some throttle body issues. While talking to the seller he told me that the alternator had recently gone bad and that he had replaced it with a junkyard one. He assured me he'd had it tested and it tested out well. 

 

I drove the vehicle a few days to figure out some of it's quirks before I dove into the project. After a thorough cleaning of the engine bay I drove about five miles, noticing some serious electrical malfunctions with the gauges and the headlights dimming, and eventually the car died from a lack of electrical power. Obviously, I jumped at the alternator. Pulled it and the battery out. Took the battery to work (I work at a Chevrolet dealership) for a full charge and a diagnostic to make sure that it was not in fact the problem. Battery tested great, so I charged it fully and put it back in the car. Next came the alternator. Again, took it down, got it bench tested and it too tested out fine. 

 

So I came home, installed everything again, hit the key and it starts right up. I hopped in to take it for a test drive and made it maybe 100 yards down the road before the whole vehicle just shuts off like someone hit an on/off switch. The only time I've ever had electrical failure to that extent is when the battery cables aren't properly hooked up, so I checked everything out and it's all hooked up fine. Tried to jump it with my Jeep and the motor still wouldn't turn over. 

 

So like I said, I'm a newbie to the Subaru world, so I was wondering if there's some engine ground that may have come loose that wasn't readily apparent or if there might be a fuse or relay that would cause these symptoms. It's very clearly all of a sudden not getting power to the starter and I can't figure out why. Any help is appreciated.

 

Edited October 28, 2014 by jjesien

[john in KY]

I'd suspect the battery cables. Look for corrosion just behind the post connectors. 

[jjesien]

No, I thoroughly cleaned both the posts and the connectors. A friend of mine theorized it could be that the ECU just up and quit, but that seemed like a bit of a stretch to me.

[1 Lucky Texan]

when you tried to jump it, was there any clicking?

[Gloyale]

Fusible link in the under hood fuse box.

[heartless]

just because the ends are clean does not mean the cable itself is in good shape - check closely for signs of corrosion up under the insulation of BOTH cables. if either looks like it has corrosion up there, they may need to be replaced.

 

These cars a bit fussy about grounds, too - make sure they are clean and tight (working from memory here, so may be a bit off on a couple of these) - main battery ground at the tranny bellhousing; another smaller one on the upper rad support, in front of the battery/above drivers side headlight; there are a couple of engine harness grounds on the back of the motor, near the tranny bellhousing, one on the passenger side (on one of the intake bolts I think), one just a bit to drivers side of center...

 

Look around for others, making sure they are all clean and tight.

 

check the underhood fusebox over as well.

 

the ECUs on these rarely fail - not saying it doesnt ever happen, but pretty rare.