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Baja Chokes + Radio & Instruments Go Dead


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Yesterday my 2003 Baja (non turbo, MT) bucked as I started out from a stop and continued to have power loss issues as I shifted through the gears.  At the same time, the radio went silent and all instruments/indicators dropped down to their at-rest positions.   At a stop, the engine idle was slow and stumbling.  I was only several blocks from home, so turned around and crawled back.  The instruments and radio started working again and engine response coincidentally improved for a few brief periods as I drove.

When I got home I checked the battery terminal connections and they were solid.  Any ideas on what might be wrong?  I don't remember seeing the MIL come on after any of these events, so I'm not sure if any trouble code may have been recorded.  I'd like to know what I might be getting myself into with regard to a repair bill if this turns out not to be a DIY fix.  I bought this car three years ago and it hasn't needed anything.  It has 127K miles on it.

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That all these functionally-unrelated systems are failing at the same time points to a global electrical fault - as the previous posters suggested, portions of the circuit that are common to pretty much everything.

Get the FACTORY TSM schematic, follow the lines, then (and I know this is going to sound really unscientific) start wiggling stuff.  That the radio is failing should be a big help - you can turn it on, lift the hood, and push wires around (and remove/reinsert relays and fuses) until you replicate the failure.  As suggested, the problem is probably in the main power distribution area.   (A few months ago I chased down a similarly transient failure in my 2002 Forester ABS - it was caused by a corroded fuse termination in the fuse/relay box.)  As you remove each fuse and relay, look down into the terminals, and if they aren't clean and bright you're probably getting close.

This is very much a DIY thing, because chasing down intermittent electrical failures is more a job for time and patience than it is of skill, and you could easily get into thousands worth of shop time if it's a nasty one.

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Before we go nuts on diagnostics, has anyone pulled out a voltmeter to actually check the charging voltage and battery voltage?

 

If I was to take a wild guess it sounds like your alternator has crapped out. What you describe is typical of running off the battery.

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1 minute ago, nipper said:

Before we go nuts on diagnostics, has anyone pulled out a voltmeter to actually check the charging voltage and battery voltage?

If I was to take a wild guess it sounds like your alternator has crapped out. What you describe is typical of running off the battery.

Perfectly valid point.  My experience with alternator failures has been "sudden death" rather than intermittent behaviour, but there's no reason it couldn't be the latter (e.g. a flakey regulator).

The only problem is that it's harder to "force" alternator misbehaviour than it is to wiggle a bad connection.  Best (cheap and easy) way to debug it is to drop in a replacement alternator (esp. from the junkyard) and see if the symptoms recurr.

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Its easy actually. urn everything on, rev the engine to 1800 RPM and take a volt reading. If its no 13.9 its a bad alt. Every alt I ever had go bad went this way. Fine during the day but cant keep up at night or in bad weather when everything is on.

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Well, 13.5 (or not too much more) is okay - that's what a 12V lead-acid requires for charging.

Thing is, rp2813 is reporting somewhat intermittent behaviour, so while the voltmeter may say it's fine while it's in the driveway, 20 miles down a bumpy road may be a different matter.  A tanked alternator is easy; to manually induce the failure in an intermittent one not so much.  That's why, if it's reading >13.5V in the driveway, the best way to determine whether it's at fault is to replace it, keep driving, and see if the problem reappears.

But there's no disagreement here - all of the above answers are correct.

 

Edited by jonathan909
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Thanks for all the good advice.  One thing that a reply above reminded me about is that ever since I've had the car, the radio has had an issue where, after starting the car, it remains dead even though it was working and turned on when the car last ran.  Within a period of half a minute or sometimes as long as a couple of minutes, the radio comes to life and remains operating without any interruptions.  It's doesn't bother me enough to try to resolve it.  I don't think this is related to the coughing and instrument failure, but I can't trust the radio for any power tests either.  Also, I forgot to mention that while everything is dead, the turn signal's flasher module operates with a very rapid clicking sound.  I don't know if that information is of any additional use for diagnosing things.

I don't have the shop manual for this car.  They're prohibitively expensive from what I've seen for sale on line.  I have a highly abridged manual from an aftermarket publisher, and it doesn't go into much detail.  I'll see what I can find on line for guidance regarding some of the components mentioned above.  I haven't been to a wrecking yard in years, so investigating this problem could include a fun outing!

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Aftermarket manuals (e.g. Haynes), while broadly useful, are never accurate enough for this kind of work - there's just too much subtle deviation in the wiring from year to year.  Look around here and you'll find  links to free downloadable sources for the authentic Subaru TSMs.

 

Edited by jonathan909
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I left the Baja on the street yesterday so I could get my other car out.  Today I moved it back onto the driveway.  It started up fine and I let it run while I moved the other car out of the way.  I hopped into the Baja, shifted into 1st and with that the trouble started again.  It continued until I had it where I wanted it on the driveway so I could work on it, and I decided to take my foot off the gas and let it struggle.  It soon died and there was a new beeping sound I hadn't heard before.  I tried to restart it and got just a buzz, like a dead battery.  Pulled the battery and took it to an auto parts store for testing.  It was dead, but it took a charge, however the diagnosis was that it was shot.  I have no reason to think otherwise. 

It was too late to install the new battery, so I'll do that tomorrow.  My multi-meter is kaput so I need to get a new one to check the charging system.  With any luck, this may turn out to be the easiest of fixes.

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Auto electrics 101:

The battery s a storage device used to start the car and make up any output defacits by the altenator (like at a traffic light)

The Alt recharges the storage battery and runs the car.

 

The Alt is not putting out enough power to meet the demand of the load, so the car runs out of battery power and starts running badly. The battery can rebuild itself if it sits long enough and hasnt been damaged by the discharge. These batteries arent designed for deep discharge. Just replacing the battery will not fix the issue, it may delay it but wont fix it. This isnt rocket science.

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It's worth mentioning too that an excellent long-term investment (in addition to the basics, like a DVM and battery charger) is a load tester.

Not just useful at home for diagnosing these sorts of problems, but the only way to find a good battery at a self-serve junkyard.  I haven't spent full pop for a battery in many years, and we need good ones, since -40 is not unusual around here in the winter.

 

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The new battery has resolved the trouble for now.  I'm not by any means convinced that this was the problem, but it may take some driving to recreate it.  I ran errands today and also let the car sit for about 45 minutes with the radio going.  I had forgotten that several months ago I had an appointment and a passenger in the car waited outside.  It took a good 30-45 minutes and when I got back out to the car, it was dead simply from having the radio on (and whatever else might be operable with the key in that position).  So the old battery was for sure on its way out.  The colder temps this time of year likely put it over the edge.

I've had batteries fail on me in different ways over the years, but most have been fine one day and dead the next without any warning signs.  I had a '64 Ford Galaxie that developed an intermittent loud hum in the radio before the battery failed, but the engine issue along with the dead instrument panel and radio on the Baja was far more dramatic.  I'd like to think a new battery has fixed the problem, but there's a reason why you won't find me in Reno or Vegas very often . . .

I'll be getting myself a new muti-meter this week to check the alternator.  If there's anything more to report, I'll post it here.

Thanks for the on-line shop manual resources.  I did find a downloadable one that covered 2003, so will use that site for future reference.

Edited by rp2813
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I ran the checks suggested above.  The multi-meter reading was 14.25V at idle, and a little higher when I increased RPM. 

When I think about how the old battery failed, I have to wonder if a component within the battery may have been compromised in a way that caused the intermittent problems with the instruments and engine idle/performance.  Presumably there are controls for these systems that are electronic, which were impacted by the battery's fatal issues.  For now, it appears the alternator is working properly and that the weak old battery finally gave up.

P.S.  While searching craigslist for parts, I found a like new complete 2003 Legacy shop manual set for cheap.  I'm in the process of arranging to complete the deal.

Edited by rp2813
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How much higher is a little higher above idle?

You don’t want to see anything above 14.8v when charging. This too would indicate a dead alternator. Could make for a good welder but battery charging is no longer an option for that unit. 

Monitor, it’ll rear it’s ugly head soon enough if it’s alternator related!

Cheers 

Bennie

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Sure, but overcharging can cause battery failure, and it sounds like you're nearing the upper limit.

To answer your earlier speculation, there really aren't any "components" within a regular lead-acid battery other than plates and acid.  But charging at too high a voltage will mess up the cell chemistry, alter the plates, and boil away the acid.  If it were me I'd be fetching an alternator from the boneyard rather than risking messing up a new battery.

 

 

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10 hours ago, jonathan909 said:

  If it were me I'd be fetching an alternator from the boneyard rather than risking messing up a new battery.

 

 

this...

A bad battery can kill an alternator by making it work more to try to recharge it...

A bad alternator can kill a battery by a)undercharging, leaving the battery to make up the difference while the car is running and thereby discharging it, or b) overcharging and cooking away the acid, causing damage to the plates...

Take the car to your local auto parts store... most will run a free charging system diagnostic for you if you ask. the system will be checked with the car off, and with it running at idle, and they will (should) ask you bring the rpms up to check it at "driving" speed.. also with all accessories off, and again with accessories on (lights, radio, heat, etc).

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I guess I'm missing something.  The voltage ranged between 14.25 and 14.28 when I tested with a multi-meter.  Unless Subarus are different from the average car, the range for a properly working alternator is between 13.8 and 14.8v.  My readings were in the middle of that range with the engine at idle and no accessories activated, at idle with blower, headlights, radio and rear defroster activated, and with those same accessories activated under increased/cruising RPM.   I'm not understanding why it's even necessary to have the alternator checked by someone else.  What am I not getting about this?

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You're not missing anything.  The parts store doesn't have any magic, just a voltmeter like yours.

I mean, if someone had a reason to really characterize an alternator, he'd have a test jig that could spin it at selected RPMs and a variable load so a determination of the power (that is, both the voltage and current) the DUT (device under test) can deliver at specified speeds and loads could be made.  But you don't need to do that, and presumably the parts store can't either.

 

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Thanks.  I've been thinking about this and am pretty sure that it's been so long since a battery has demonstrated signs of failure on me while driving that this Baja is likely my first car with any sort of computerized operation to have this happen.   I'm attributing the engine issues to the temporary loss of computerized functions. 

Interestingly, since replacing the battery the radio has been working properly.  This is why I was thinking the battery guts like plates could have deteriorated and created intermittent problems before worsening to the point of making it difficult to keep the engine running.  My knowledge of electrical theory is just enough to make me dangerous, but I'm pretty sure that you need a sound battery in order for the alternator to do its job.

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