As some of you know, I have a 1990 Subaru Liberty/Legacy wagon. A friend and I thought that is has a dud alternator, but from a little bit of research on the net about the issue, it could be something else. Considering I get my licence tomorrow, I need my car to be reliable and not run out of electricity. Before I go spending $175 on an alternator tomorrow, want to make sure it isn't something else.
What is happening though, is that the alternator will charge the battery for maybe an hour or so, then the dash lights will start flickering on and off really quickly, which is generally a sign something with the electrics is at fault, it seems to be when the car goes under about 2000-2500RPM, but not in every gear (sometimes 2nd, sometimes 4th, sometimes 5th but never 3rd or First). To avoid this I shift in to a lower gear to keep the revs up, therefore killing the fuel efficiency. It will sort itself out after a bit and only flicker on once or twice again. It does seem to be random and sometimes on some very long drives it has only flickered for a second or two.
Sounds like an alternator on its way out to me. You could pull the alt and take it to a parts store, some will test it for free. Although an intermittent failure like that might not show up on the test... worth a shot anyway before you go drop the cash on a new one.
Usually if the Subaru's computer thinks the battery or alternator is going bad, itll light up the battery and brake light. May not be the case with this though.
Id probably start first by checking and cleaning grounds, some factory grounds are known for being put on top of paint and eventually having rust build up. Theres.. 5-6 in the engine bay, atleast on my Impreza. On mine, theres one on each frame rail, one near the intake manifold, and two on the left strut tower. May be forgetting some.
If that doesnt work, id say its the alternator.
If you have a voltmeter and can stop the car while its doing it, you could check the voltage the alternator is putting out as well as what the battery is at
[QUOTE=TweaK2007;42161964]Sounds like an alternator on its way out to me. You could pull the alt and take it to a parts store, some will test it for free. Although an intermittent failure like that might not show up on the test... worth a shot anyway before you go drop the cash on a new one.[/QUOTE]
Problem with that though, it takes ~50 minutes to an hour for that to happen. Thanks for the tip though.
[editline]12th September 2013[/editline]
[QUOTE=FordLord;42162099]Usually if the Subaru's computer thinks the battery or alternator is going bad, itll light up the battery and brake light. May not be the case with this though.
Id probably start first by checking and cleaning grounds, some factory grounds are known for being put on top of paint and eventually having rust build up. Theres.. 5-6 in the engine bay, atleast on my Impreza. On mine, theres one on each frame rail, one near the intake manifold, and two on the left strut tower. May be forgetting some.
If that doesnt work, id say its the alternator.
If you have a voltmeter and can stop the car while its doing it, you could check the voltage the alternator is putting out as well as what the battery is at[/QUOTE]
Checked all of the grounds, which are fine and clean. Turns out they are in the exact same spot on the first gen Libertys. It's not just the battery and brake light coming on though, it's everything on the dash coming on.
What I might do is borrow my dad's voltage meter after I get my licence, then keep that in the car to see if it happened.
As both of you guys have said though, it sounds like a dud alternator, I just thought I would check first.
That sounds like a bad ECU ground to me. 98% sure.
So all the warning lights flicker on and off? I read it as if all the lights shut off and back on.
That could be something different entirely, but i think itd most likely be the alternator
[editline]12th September 2013[/editline]
[QUOTE=bradley;42162271]That sounds like a bad ECU ground to me. 98% sure.[/QUOTE]
It could be, ive just never heard of an ECU ground issue in a Subaru, unless its been removed at one point and not put back properly. If it is, the ECU is on the passenger side where your feet go. You can pull up the carpet, then the ECU is covered by a metal plate that you can unbolt. Im not exactly sure where the ECU ground is, but id assume its on the transmission tunnel
[QUOTE=FordLord;42162325]So all the warning lights flicker on and off? I read it as if all the lights shut off and back on.
That could be something different entirely, but i think itd most likely be the alternator[/QUOTE]
Flickering on and off extremely quickly (10+ times a second) or they all stay solid for a bit. As I said, the higher the RPM while it's happening, it stops but as soon as it lowers to under about 2500rpm, it starts happening again.
This happened to the girlfriend's S13. But it was doing it with all illumination. Exterior and interior lights, it would flicker and dim. It would happen on and off until one day it just completely died when I was driving, (was out in the middle of nowhere too at that!)
It was a toasted alternator. I took it out, tested it at the part's store where I worked and it was shot. I just went to a yard and got a decent alternator off a similar car and bolted it up. Works fine until today. Hopefully it will last.
Check the charging voltage. Perhaps the regulator is going and high RPM's are spiking the computer until it resets.
Edited: The regulator is on the Alternator, of course.
Could be regulator, yeah. I'd really have to see what it was doing firsthand.
If there's audible clicks during the flickering, it's an ECU ground for sure. But if not, I'm guessing regulator as well. Get a voltmeter after the regulator pins.
[QUOTE=bradley;42162679]Could be regulator, yeah. I'd really have to see what it was doing firsthand.
If there's audible clicks during the flickering, it's an ECU ground for sure. But if not, I'm guessing regulator as well. Get a voltmeter after the regulator pins.[/QUOTE]
There are no audible clicks while it is happening. I'll be sure to give it a go tomorrow then as I don't have a voltmeter myself or the means of going out to get one.
Thanks for everyone's help
[QUOTE=Slade Xanthas;42162415]I'd expect that would be rather scary during a storm at night.[/QUOTE]
I've actually had such thing happen to me, except it also rained.
Although it was the connector to the alternator status light that were busted.
Somehow the voltage regulator in the particular alternator in my car refuses to work if that status light isn't fully functional.
Thank god a prechamber diesel engine only needs power for the fuel solenoid once it actually is running or I would've been stuck in the middle of bumfuck nowhere a late sunday night.
Can you hook up a multimeter to the battery when this happens, I had a loose alternator ground where it would charge intermittently, the only way I knew is because there was a volt gauge I installed.
[QUOTE=Animosus;42161724]
What is happening though, is that the alternator will charge the battery for maybe an hour or so, then the [B]dash lights will start flickering on and off really quickly, which is generally a sign something with the electrics is at fault, it seems to be when the car goes under about 2000-2500RPM[/B], but not in every gear (sometimes 2nd, sometimes 4th, sometimes 5th but never 3rd or First). To avoid this I shift in to a lower gear to keep the revs up, therefore killing the fuel efficiency. It will sort itself out after a bit and only flicker on once or twice again. It does seem to be random and sometimes on some very long drives it has only flickered for a second or two.[/QUOTE]
My previous car (a Ford) did this when the alternator started to fail. It would usually begin to flash the electrical system warning light within ten minutes of starting to drive, and would come on-and-off every couple minutes. Revving the engine would make the light disappear, so I would usually drive it with overdrive disengaged to keep it revving in 3rd gear.
Although, on mine it would only flicker the [I]warning[/I] lights, not the entire dashboard / exterior lightning.
Well actually, easy test for low speed alternator output... unhook the battery ground and see if it will stay running with the headlights on. I had the voltage regulator on mine go out before and all the lights would flicker a bunch but I guess not enough to trigger any warning lights. It stopped once I replaced the alt.
^^^^ Don't do that on new cars with computers.
[QUOTE=clutch2;42185536]^^^^ Don't do that on new cars with computers.[/QUOTE]
Saying "newer cars with computers" is actually a complete lie, anything pre-OBD2b would be fine with that trick.
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