97 4Runner Electrical problem

Reply
 
LinkBack Thread Tools Display Modes
Old 25 Dec 2009, 07:39 pm   #1 (permalink)
JMc
Guest
  • Posts: n/a
  • User Status:


Default 97 4Runner Electrical problem

My 1997 4Runner with 203,000 miles has begun exhibiting a strange problem
that seems to be electrical. While driving the engine stumbles, the brake
light on the dash comes on, then in most cases the engine catches again, the
brake light goes out and I drive on. So far it has never actually stalled
the engine entirely, but I've lost power to a dangerous extent. Often this
happens two, three, as many as six times in succession before it seems to
clear. I've noticed a high-pitched small motor bearing noise from under the
hood at about the same time, as though a bearing in perhaps an alternator or
other similar sized unit is wearing out. Ok, I understand it is an old
enough truck that any of these things could be normal wear and tear, but it
is Christmas, and a long weekend till I might get a chance to have diag
codes read. I'm not even sure anything will have registered. I am most
puzzled by the clear connection between the brake light and the apparent
electrical problem.

Any ideas I might look at tomorrow, any hope that the brake light indicator
is just an indicator that some code is being logged?

Thanks,
Jere

  Reply With Quote
Old 25 Dec 2009, 10:06 pm   #2 (permalink)
Anyolmouse
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem


"JMc" <mcdonaldjc@verizon.net> wrote in message
news:hh3m07$7cl$1@news.eternal-september.org...
> My 1997 4Runner with 203,000 miles has begun exhibiting a strange

problem
> that seems to be electrical. While driving the engine stumbles, the

brake
> light on the dash comes on, then in most cases the engine catches

again, the
> brake light goes out and I drive on. So far it has never actually

stalled
> the engine entirely, but I've lost power to a dangerous extent. Often

this
> happens two, three, as many as six times in succession before it seems

to
> clear. I've noticed a high-pitched small motor bearing noise from

under the
> hood at about the same time, as though a bearing in perhaps an

alternator or
> other similar sized unit is wearing out. Ok, I understand it is an

old
> enough truck that any of these things could be normal wear and tear,

but it
> is Christmas, and a long weekend till I might get a chance to have

diag
> codes read. I'm not even sure anything will have registered. I am

most
> puzzled by the clear connection between the brake light and the

apparent
> electrical problem.
>
> Any ideas I might look at tomorrow, any hope that the brake light

indicator
> is just an indicator that some code is being logged?
>
> Thanks,
> Jere
>


When I had an alternator problem in my '87 PU the brake light and
alternator (charge) light both came on. Does the charge light come on
when you turn the key prior to starting the engine? Maybe the bulb is
burned out?

How long has it been since the alternator was replaced? 203,000 miles is
a long time for the original to last.

FWIW, I had the alternator freeze up in a Chevy Lumina while doing 6o
mph. It stopped the engine completely and I slid off of the highway. I
was just outside of a small town and had some of my tools with me. So I
took off the serpentine belt and drove it to the only garage for miles
around.

--
We have met the enemy and he is us-- Pogo

Anyolmouse


  Reply With Quote
Old 25 Dec 2009, 10:24 pm   #3 (permalink)
JMc
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

Thanks for suggestions:
The alternator is original, (as is everything else but fluids, tires, brake
pads and the throttle positioning sensor). Charge indicator does illuminate
when I turn key on before starting, but has not yet ever lit during one of
my episodes. I'll stay off highways and below 60 till I sort this out.
Fortunately, it is manual trans and I can control potential skidding with
application of clutch. I'll give an update after some more thought and
investigation tomorrow.

Thanks again

"Anyolmouse" <Anyolmouse@invalid.invalid> wrote in message
news:Y5fZm.10091$Gf3.313@newsfe18.iad...
>
> "JMc" <mcdonaldjc@verizon.net> wrote in message
> news:hh3m07$7cl$1@news.eternal-september.org...
>> My 1997 4Runner with 203,000 miles has begun exhibiting a strange

> problem
>> that seems to be electrical. While driving the engine stumbles, the

> brake
>> light on the dash comes on, then in most cases the engine catches

> again, the
>> brake light goes out and I drive on. So far it has never actually

> stalled
>> the engine entirely, but I've lost power to a dangerous extent. Often

> this
>> happens two, three, as many as six times in succession before it seems

> to
>> clear. I've noticed a high-pitched small motor bearing noise from

> under the
>> hood at about the same time, as though a bearing in perhaps an

> alternator or
>> other similar sized unit is wearing out. Ok, I understand it is an

> old
>> enough truck that any of these things could be normal wear and tear,

> but it
>> is Christmas, and a long weekend till I might get a chance to have

> diag
>> codes read. I'm not even sure anything will have registered. I am

> most
>> puzzled by the clear connection between the brake light and the

> apparent
>> electrical problem.
>>
>> Any ideas I might look at tomorrow, any hope that the brake light

> indicator
>> is just an indicator that some code is being logged?
>>
>> Thanks,
>> Jere
>>

>
> When I had an alternator problem in my '87 PU the brake light and
> alternator (charge) light both came on. Does the charge light come on
> when you turn the key prior to starting the engine? Maybe the bulb is
> burned out?
>
> How long has it been since the alternator was replaced? 203,000 miles is
> a long time for the original to last.
>
> FWIW, I had the alternator freeze up in a Chevy Lumina while doing 6o
> mph. It stopped the engine completely and I slid off of the highway. I
> was just outside of a small town and had some of my tools with me. So I
> took off the serpentine belt and drove it to the only garage for miles
> around.
>
> --
> We have met the enemy and he is us-- Pogo
>
> Anyolmouse
>
>

  Reply With Quote
Old 26 Dec 2009, 01:17 am   #4 (permalink)
Jeff
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

Do you have the optional 4 wheel brake equalizer gadgetry, AntiLock, or
whatever they call it? "Brake Light" makes ME think BRAKES! I never
liked the looks of all that plumbing...

Or... the optional automatic locking, i.e., vacuum operated, front
differential comes to mind. Another plumber's bad dream.

Check your wiring, including grounds?

Yea, I dread those unpredictable power-drops in the middle of nowhere!

Take care, and Good Luck!
  Reply With Quote
Old 26 Dec 2009, 07:44 pm   #5 (permalink)
JMc
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

I do ABS brakes, though they are factory. But you raise a good point. I am
now thinking the Brake light on the dash is a result rather than a source
indicator. My sense is the electrical interruption is long enough for the
ABS circuitry to sense and it is lighting the dash light to indicate they
are not ready for emergency stopping.

I am back to tracing the electrical feeds from battery, alternator, starter
and ground. It's pouring rain, melting our snow pack, and even a dry garage
is not a comfortable place for crawling around, but better than a ditch
somewhere.

Thanks,
Jere

"Jeff" <Not@dot.net> wrote in message
news:4b35a9ea$0$30841$822641b3@news.adtechcomputer s.com...
> Do you have the optional 4 wheel brake equalizer gadgetry, AntiLock, or
> whatever they call it? "Brake Light" makes ME think BRAKES! I never liked
> the looks of all that plumbing...
>
> Or... the optional automatic locking, i.e., vacuum operated, front
> differential comes to mind. Another plumber's bad dream.
>
> Check your wiring, including grounds?
>
> Yea, I dread those unpredictable power-drops in the middle of nowhere!
>
> Take care, and Good Luck!


  Reply With Quote
Old 26 Dec 2009, 09:15 pm   #6 (permalink)
Jeff
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

Your reasoning appears sound. Of course, this is the type of problem
that may not reappear, leaving you clueless as to whether all the
fooling around did any good or not. And, you're probably inadvertently
erasing any codes. But, what else can you do? How much more trouble
would it have been to include OBDII scan and clear functions in the
operating controls of the vehicle (not requiring the acquisition and use
of a scan tool)?

I say optional ABS, since my '98 Tacoma does NOT have ABS, nor the
automatic locking front differential. 4Runners may have had ABS standard.

Does the ABS controller store codes?

JMc wrote:
> I do ABS brakes, though they are factory. But you raise a good point.
> I am now thinking the Brake light on the dash is a result rather than a
> source indicator. My sense is the electrical interruption is long
> enough for the ABS circuitry to sense and it is lighting the dash light
> to indicate they are not ready for emergency stopping.
>
> I am back to tracing the electrical feeds from battery, alternator,
> starter and ground. It's pouring rain, melting our snow pack, and even
> a dry garage is not a comfortable place for crawling around, but better
> than a ditch somewhere.
>
> Thanks,
> Jere
>
> "Jeff" <Not@dot.net> wrote in message
> news:4b35a9ea$0$30841$822641b3@news.adtechcomputer s.com...
>> Do you have the optional 4 wheel brake equalizer gadgetry, AntiLock,
>> or whatever they call it? "Brake Light" makes ME think BRAKES! I
>> never liked the looks of all that plumbing...
>>
>> Or... the optional automatic locking, i.e., vacuum operated, front
>> differential comes to mind. Another plumber's bad dream.
>>
>> Check your wiring, including grounds?
>>
>> Yea, I dread those unpredictable power-drops in the middle of nowhere!
>>
>> Take care, and Good Luck!

>

  Reply With Quote
Old 04 Jan 2010, 01:15 pm   #7 (permalink)
JMc
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

There are no codes logged or pending. As an intermittent, it has been very
difficult to diagnose, but my brother on holiday visit is convinced it is a
crankshaft position sensor. He tells me it is a perfect symptom match on
the interruption of ignition, and very easily can explain trouble starting.
We (ok he) is not exactly sure of the high-pitch bearing noise, and
unfortunately that has not exhibited itself this week. I'll run a tank of
gas through after replacement and report back if anyone is interested.

Jere

"JMc" <mcdonaldjc@verizon.net> wrote in message
news:hh3m07$7cl$1@news.eternal-september.org...
> My 1997 4Runner with 203,000 miles has begun exhibiting a strange problem
> that seems to be electrical. While driving the engine stumbles, the brake
> light on the dash comes on, then in most cases the engine catches again,
> the brake light goes out and I drive on. So far it has never actually
> stalled the engine entirely, but I've lost power to a dangerous extent.
> Often this happens two, three, as many as six times in succession before
> it seems to clear. I've noticed a high-pitched small motor bearing noise
> from under the hood at about the same time, as though a bearing in perhaps
> an alternator or other similar sized unit is wearing out. Ok, I
> understand it is an old enough truck that any of these things could be
> normal wear and tear, but it is Christmas, and a long weekend till I might
> get a chance to have diag codes read. I'm not even sure anything will
> have registered. I am most puzzled by the clear connection between the
> brake light and the apparent electrical problem.
>
> Any ideas I might look at tomorrow, any hope that the brake light
> indicator is just an indicator that some code is being logged?
>
> Thanks,
> Jere


  Reply With Quote
Old 06 Jan 2010, 01:22 pm   #8 (permalink)
JMc
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

Feels like I can confidently confirm the Crankshaft Positioning Sensor was
the source of this problem. A little more obscure than I expected, but at
203k miles, just about anything could be wearing out. This was not cheap,
hope to get another 50k miles now.

Jere

"JMc" <mcdonaldjc@verizon.net> wrote in message
news:hhtb8o$4jp$1@news.eternal-september.org...
> There are no codes logged or pending. As an intermittent, it has been
> very difficult to diagnose, but my brother on holiday visit is convinced
> it is a crankshaft position sensor. He tells me it is a perfect symptom
> match on the interruption of ignition, and very easily can explain trouble
> starting. We (ok he) is not exactly sure of the high-pitch bearing noise,
> and unfortunately that has not exhibited itself this week. I'll run a
> tank of gas through after replacement and report back if anyone is
> interested.
>
> Jere
>
> "JMc" <mcdonaldjc@verizon.net> wrote in message
> news:hh3m07$7cl$1@news.eternal-september.org...
>> My 1997 4Runner with 203,000 miles has begun exhibiting a strange problem
>> that seems to be electrical. While driving the engine stumbles, the
>> brake light on the dash comes on, then in most cases the engine catches
>> again, the brake light goes out and I drive on. So far it has never
>> actually stalled the engine entirely, but I've lost power to a dangerous
>> extent. Often this happens two, three, as many as six times in succession
>> before it seems to clear. I've noticed a high-pitched small motor
>> bearing noise from under the hood at about the same time, as though a
>> bearing in perhaps an alternator or other similar sized unit is wearing
>> out. Ok, I understand it is an old enough truck that any of these things
>> could be normal wear and tear, but it is Christmas, and a long weekend
>> till I might get a chance to have diag codes read. I'm not even sure
>> anything will have registered. I am most puzzled by the clear connection
>> between the brake light and the apparent electrical problem.
>>
>> Any ideas I might look at tomorrow, any hope that the brake light
>> indicator is just an indicator that some code is being logged?
>>
>> Thanks,
>> Jere

>

  Reply With Quote
Old 06 Jan 2010, 05:09 pm   #9 (permalink)
Jeff
Guest
  • Posts: n/a
  • User Status:


Default Re: 97 4Runner Electrical problem

Thanks for the update! I wonder if a (more readily available) sensor
might interchange. A Tacoma is rare in the upullit yards, but a Camry
or Lexus are there for the picking.

NO error codes! Damn! Any more screaming?


JMc wrote:
> Feels like I can confidently confirm the Crankshaft Positioning Sensor
> was the source of this problem. A little more obscure than I expected,
> but at 203k miles, just about anything could be wearing out. This was
> not cheap, hope to get another 50k miles now.
>
> Jere
>
> "JMc" <mcdonaldjc@verizon.net> wrote in message
> news:hhtb8o$4jp$1@news.eternal-september.org...
>> There are no codes logged or pending. As an intermittent, it has been
>> very difficult to diagnose, but my brother on holiday visit is
>> convinced it is a crankshaft position sensor. He tells me it is a
>> perfect symptom match on the interruption of ignition, and very easily
>> can explain trouble starting. We (ok he) is not exactly sure of the
>> high-pitch bearing noise, and unfortunately that has not exhibited
>> itself this week. I'll run a tank of gas through after replacement
>> and report back if anyone is interested.
>>
>> Jere
>>
>> "JMc" <mcdonaldjc@verizon.net> wrote in message
>> news:hh3m07$7cl$1@news.eternal-september.org...
>>> My 1997 4Runner with 203,000 miles has begun exhibiting a strange
>>> problem that seems to be electrical. While driving the engine
>>> stumbles, the brake light on the dash comes on, then in most cases
>>> the engine catches again, the brake light goes out and I drive on.
>>> So far it has never actually stalled the engine entirely, but I've
>>> lost power to a dangerous extent. Often this happens two, three, as
>>> many as six times in succession before it seems to clear. I've
>>> noticed a high-pitched small motor bearing noise from under the hood
>>> at about the same time, as though a bearing in perhaps an alternator
>>> or other similar sized unit is wearing out. Ok, I understand it is
>>> an old enough truck that any of these things could be normal wear and
>>> tear, but it is Christmas, and a long weekend till I might get a
>>> chance to have diag codes read. I'm not even sure anything will have
>>> registered. I am most puzzled by the clear connection between the
>>> brake light and the apparent electrical problem.
>>>
>>> Any ideas I might look at tomorrow, any hope that the brake light
>>> indicator is just an indicator that some code is being logged?
>>>
>>> Thanks,
>>> Jere

>>

  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 07:55 pm.

Attribution:
Autoblog
Powered by Yahoo Answers



ToyotaLexusForum.com is an unofficial community for car enthusiasts. ToyotaLexusForum.com is not affiliated with Toyota Motor Corporation in any way.
Toyota Motor Corporation does not sponsor, support, or endorse ToyotaLexusForum.com in any way.
Copyright/trademark/sales mark infringements are not intended or implied.