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From: JMc on 25 Dec 2009 19:39 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
From: Anyolmouse on 25 Dec 2009 22:06 "JMc" <mcdonaldjc(a)verizon.net> wrote in message news:hh3m07$7cl$1(a)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
From: JMc on 25 Dec 2009 22:24 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(a)invalid.invalid> wrote in message news:Y5fZm.10091$Gf3.313(a)newsfe18.iad... > > "JMc" <mcdonaldjc(a)verizon.net> wrote in message > news:hh3m07$7cl$1(a)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 > >
From: Jeff on 26 Dec 2009 01:17 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!
From: JMc on 26 Dec 2009 19:44
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(a)dot.net> wrote in message news:4b35a9ea$0$30841$822641b3(a)news.adtechcomputers.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! |