91 Ls400 died while driving
02-04-15, 03:58 PM
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91 Ls400 died while driving
Hi I have a 1991 Lexus LS400 with 211k miles on it.
Recently I was driving it in slow traffic, and while I was sitting at a red light the dash board started to light up with all these warning signals, low oil, emergency brake on, etc, when the light turned green I accelerated and all of the lights went away and my dash went back to normal. I then got stuck at another red light and the same thing occurred this time however the whole dashboard started flickering and becoming dimmer and then the engine turned off. I tried to turn the car back on but nothing happened. I had to call AAA and they said it was probably my alternator, the AAA guy zapped my battery and told me to turn off all the vents and the headlights. He also said that when I come to a stoplight I should put the car in neutral and rev the engine so that the car doesn't die again. I drove it all the way to my mechanic and parked it in his lot. I turned off the car and decided to walk home, but just for the heck of it I tried to start the car and it started it up normally. My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine.
Anybody have any idea what the problem is?
The alternator is about 4 years old, and I just got a new battery about 4-5 months ago.
Recently I was driving it in slow traffic, and while I was sitting at a red light the dash board started to light up with all these warning signals, low oil, emergency brake on, etc, when the light turned green I accelerated and all of the lights went away and my dash went back to normal. I then got stuck at another red light and the same thing occurred this time however the whole dashboard started flickering and becoming dimmer and then the engine turned off. I tried to turn the car back on but nothing happened. I had to call AAA and they said it was probably my alternator, the AAA guy zapped my battery and told me to turn off all the vents and the headlights. He also said that when I come to a stoplight I should put the car in neutral and rev the engine so that the car doesn't die again. I drove it all the way to my mechanic and parked it in his lot. I turned off the car and decided to walk home, but just for the heck of it I tried to start the car and it started it up normally. My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine.
Anybody have any idea what the problem is?
The alternator is about 4 years old, and I just got a new battery about 4-5 months ago.
02-04-15, 04:26 PM
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Sounds like some resistance exists at contacts of the ignition switch. Probably it's nearly worn out to be open soon.
02-04-15, 04:28 PM
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02-04-15, 10:18 PM
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I'd search on here for alternator failure symptoms. My guess is that you have a marginal/failing alternator.
When the alternator went on my '91, it did so suddenly and completely. It drove fine, but I had multiple random-seeming warning lights come on. Sounds just like your situation except that yours must still be making enough voltage when driving vs. at idle.
Of course, a loose connection in the alternator or a loose ground wire could cause similar behavior too.
The alternator is under the power steering pump. If it looks like it's soaked in PS fluid, that is not a good sign. How is your PS system? PS and alternator failures tend to go together - very well documented on this site.
"My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine. "
Was the problem present when he looked at it? What tests did he do to decide the alternator was good?
If you've got a voltmeter, it's pretty easy to monitor voltage at the battery with the engine running at various speeds to see if the alt is putting out the right voltage at idle as well as at 2k+ rpm.
When the alternator went on my '91, it did so suddenly and completely. It drove fine, but I had multiple random-seeming warning lights come on. Sounds just like your situation except that yours must still be making enough voltage when driving vs. at idle.
Of course, a loose connection in the alternator or a loose ground wire could cause similar behavior too.
The alternator is under the power steering pump. If it looks like it's soaked in PS fluid, that is not a good sign. How is your PS system? PS and alternator failures tend to go together - very well documented on this site.
"My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine. "
Was the problem present when he looked at it? What tests did he do to decide the alternator was good?
If you've got a voltmeter, it's pretty easy to monitor voltage at the battery with the engine running at various speeds to see if the alt is putting out the right voltage at idle as well as at 2k+ rpm.
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04-10-15, 10:56 PM
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I'd search on here for alternator failure symptoms. My guess is that you have a marginal/failing alternator.
When the alternator went on my '91, it did so suddenly and completely. It drove fine, but I had multiple random-seeming warning lights come on. Sounds just like your situation except that yours must still be making enough voltage when driving vs. at idle.
Of course, a loose connection in the alternator or a loose ground wire could cause similar behavior too.
The alternator is under the power steering pump. If it looks like it's soaked in PS fluid, that is not a good sign. How is your PS system? PS and alternator failures tend to go together - very well documented on this site.
"My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine. "
Was the problem present when he looked at it? What tests did he do to decide the alternator was good?
If you've got a voltmeter, it's pretty easy to monitor voltage at the battery with the engine running at various speeds to see if the alt is putting out the right voltage at idle as well as at 2k+ rpm.
When the alternator went on my '91, it did so suddenly and completely. It drove fine, but I had multiple random-seeming warning lights come on. Sounds just like your situation except that yours must still be making enough voltage when driving vs. at idle.
Of course, a loose connection in the alternator or a loose ground wire could cause similar behavior too.
The alternator is under the power steering pump. If it looks like it's soaked in PS fluid, that is not a good sign. How is your PS system? PS and alternator failures tend to go together - very well documented on this site.
"My mechanic took a look at it the next day and he couldn't figure out what the problem was, he said that alternator was fine. "
Was the problem present when he looked at it? What tests did he do to decide the alternator was good?
If you've got a voltmeter, it's pretty easy to monitor voltage at the battery with the engine running at various speeds to see if the alt is putting out the right voltage at idle as well as at 2k+ rpm.
I brought my car to a different mechanic and he figured out the problem. It was the alternator. He replaced it and the car works now!
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