leftoverair said:
after 30mi of highway driving the gages ceased to work, followed by
the engine hesitating/bucking then stalling. 20mins later she started
up & i made it home. the next day this happened three other times
while only driving several miles.
Similar things happened to my 1997 Outback in the Spring of 2000, on I-5 in
Northern California. The first time it happened I didn't notice the gauge
misbehavior, though I'm sure it must have occurred. What I noticed was that
the radio stopped working. I'm sure that soon thereafter I glanced at the
speedometer, something I normally do very frequently, so by the time I
looked, it must have been working. A half hour later with the radio turned
off I noticed that despite the fact that I was more or less keeping up with
the speeding I-5 traffic my speedometer read 0 km/h when I glanced at it.
The tachometer read 0 also. The engine was running as I could accelerate,
and hear the engine. Then the speedometer came back up to 120 km/ or so. The
car ran nicely for another hour or two. Then, the third time it misbehaved,
the engine quit running and fortunately I was in the slow lane and was able
to get the car off the road to the right. I couldn't get the car started and
AAA hauled it in to a Subaru dealer. They mis-diagnosed the problem as just
a failed battery. The battery had indeed failed. The alternator had taken it
out, likely by having one of its diodes short out. They replaced the
battery. I specifically asked about the alternator and was told it was fine.
They were wrong about that.
here's the low down:
-old battery was tested at 12v during idle w/ no load.
Before or after this misbehavior?
(haven't tested
new battery)
-alternator tested at 15v at local auto parts store.
When it was working correctly, yes. And when it next misbehaves?
-fusible link is still flexible. (not sure what reading i should be
getting with volt meter)
aside from checking/cleaning ground wire on the engine, i'm not sure
what else to do.
Replace that alternator before it takes out your new battery (if it hasn't
already damaged it).
The day after the battery was replaced in Chico, California, the same
misbehavior occurred on US 395 in the middle of nowhere (but fortunately not
somewhere in the backcountry where we had been earlier that morning). I was
able to nurse the car a mile or two further south into a small town where,
with the engine left running, I checked with the US Forest Service rabger
station to see if they could recommend a competent local mechanic. They did
so (recommending a guy who maintained their vehicles), the mechanic was
indeed competent, and he diagnosed the alternator misbehavior. Four hours
later, with an alternator ordered in from 60 miles away, the car was running
again.
Subarus of that era were known to have alternator problems, as later
acknowledged by Subaru USA. Mine was a Canadian Subaru (built on the same
assembly line in Indiana as the US ones) but Subaru Canada didn't
acknowledge this alternator problem. They finally acknowledged the problem
about a year and a half after Subaru USA did. Subaru Canada then compensated
me for the alternator, but not for the ruined battery. The second battery
died seven years later, so it probably hadn't been significantly damaged by
the more brief misbehavior on the second day the way the first battery had
been damaged.
One of the symptoms that the mechanic along US 395 observed was that
although the alternator output voltage was reading only a bit lower than
normal at idle speeds, making the engine run at maybe 1500 or 2000 rpm
caused the voltage to *drop* rather than increase. The faster the engine
ran, the lower the voltage became. This apparently can happen when one or
more diodes are failing. The new alternator had a normal output voltage at
idle, increasing as the engine speed was increased. Pushing a lot of
un-rectified AC into a battery is a good way to kill it fast.
Replace the alternator before it wrecks the battery.
David
