Car Battery light, coolent light on, also automatically accelarate RPM goes up n down on its own

Tiny
ANTHONYINIT
  • MEMBER
  • 1991 LEXUS LS 400
  • 120,000 MILES
Hi, I have 91' Lexus LS400. This morning my car start perfect and took me to my service station to fill my A/C gas and I noticed that my radiator coolant cap was open (maybe I forgot to close it after filling coolant the other day)so I closed it and went to church without any problem, after I came back and start the car it RPM start to go up and down without me accelerating, and my steering got so hard I couldn't even turn it, so I put the car into drive and it came back to normal. I drive back to my house and I saw my battery light and coolant light, low oil pressure light came on but I kept driving and suddenly I saw all the lights on the dash went so low (not so bright) even the A/C blower went down and A/C compressor stop working but the blower start to blow air, after few minutes of driving car died so I jump the car and start to drive not even a minutes car stops again so I checked with a near by service shop for the fault and they said it was my Alternator so I replaced the alternator with a used one and we checked for the out put power it was 13.5 but the car lights not bright.

so we kept the car run for awhile and turn off and on again and the same problem came back (RPM up and down)when the car is on drive it goes but on P/R/N get the problem. When changing gear radio shutdown n come on again, some interior lights become bright and go dim some wired things happen.

I really don't know what is really going on. Any help would be great.
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Sunday, September 25th, 2011 AT 9:11 PM

3 Replies

Tiny
ASEMASTER6371
  • EXPERT
First of all, get the used alt off the car and put a reman unit in that will work.
It failed from your coolant coming out of your radiator and shorting out the alt.
You never mentioned that you added coolant after your cap was found off. That is the reason for the light. Hope you did not damage the motor from this
steering tough from coolant on the serp belt from the rad cap missing.
Engine surge is hard to say. It could be a vacuum leak or a control issue. I think you need a shop to start with a leak down test to make sure the head gaskets are good. Then track down the other issues.

Roy
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Monday, September 26th, 2011 AT 1:05 AM
Tiny
ANTHONYINIT
  • MEMBER
Hello sir, thank you for your reply. Finally I fixed the problem I replace the ALT' with another used one which is in good condition now all the signs went off and I have no power issue.

For the RPM issue they found out that my One of the sensor is the fault (lacated center of the engine right above the water pump, it's a 3 latter name I really forgot the name) that controls the air bcuz it is malfunction I'm getting RPM issue.

Now everything is back to normal. Once I thank you for ur support.
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Monday, September 26th, 2011 AT 6:37 PM
Tiny
ASEMASTER6371
  • EXPERT
Good luck
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Monday, September 26th, 2011 AT 7:22 PM

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