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Toyota Service
Toyota Service, Lexus and Toyota expert
Category: Lexus
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Lexus sc300: A mechanic-friend wants to sell a 1992 Lexus sc300

Customer Question

A mechanic-friend wants to sell a 1992 Lexus sc300 to me; however, the car dies intermittently (after short and long drives). Sometimes it will start immediately and sometimes it has to sit a while before it will start. He changed the fuel pump and fuel ECU but the problem continues. He checked the electrical side and said he is getting "spark" from the plugs. He does not seem to know what is wrong. When the engine runs, it sounds and runs smoothly. No error codes.
Submitted: 2 years ago.
Category: Lexus
Expert:  Toyota Service replied 2 years ago.
Hello. Welcome to Just Answer. Please allow me to assist you. Could you please explain a bit better about the starting? When it dies, does it crank, or nothing happens when you turn the key to start? If you can respond with more information, I can better assist you with a remedy. Thanks
Customer: replied 2 years ago.
The following are examples of the engine cutting out/dying: (1) the engine will just die after idling for 10 to 15 minutes., (2) the engine will die on a short trip for a couple of miles - the engine will stop requiring the driver to pull over, and (3) the car will do fine getting to a destination that required 20 minutes of driving time (with no problem) but will have difficulty starting when leaving (in this case the car sat for 10 to 15 minutes). The engine cranks but it will not start when the key is turned. Sometimes it starts right away and sometimes it does not. The mechanic says he tested to see if the plugs have spark (power) and they do so he is positive that its not the problem. He says the engine at the point when it dies and does not start is not getting gas. He changed the fuel pump and the ECU.
Expert:  Toyota Service replied 2 years ago.
If this vehicle was in my shop, I would be replacing the Circuit Opening Relay. This is the device that allows the fuel pump to power up. They have been known to overheat (due to age) and disengage. This would explain a lot of your symptoms. I would recommend replacement of the circuit opening relay before I did anything else on this car. If you have any questions, please feel free to reply.Thanks for choosing Just Answer. It was a pleasure to assist you today. I trust my input to your request is satisfactory to you and meets your expectations. A positive rating would be greatly appreciated for my assistance on your inquiry. Thanks in advance and thank you again for choosing Just Answer
Customer: replied 2 years ago.
As you know the fuel ECU and fuel pump was changed. Per your suggestion, the mechanic changed the Circuit Opening Relay was changed. The mechanic test drove the car for a couple of days without problems. Thus, I took the car this morning. The following was my schedule before any problems occurred: *****from the garage to a restaurant. *****to a credit union. *****to an auto shop. *****to a bank. *****to an automobile club (AAA of Southern Cal), and*****home. *****to RadioShack and*****back home. No problems. The car sat for 1 hour and then I decided to drive my daughter to a local Subway. The minute I pulled away from the curb, the engine died. I noticed a loss of power (the car slowed) and I noticed a drop in the tach. Then the engine just cut out. I came to a stop and I started the car. It started without problems but after 15 seconds, the rpm's dropped again and the engine died. I immediately started the car and started to accelerate and the car jerked a little but the engine continued to run. I took the car around our block and the car died as I approached my house.
Expert:  Toyota Service replied 2 years ago.
I would have the alternator checked. If the system is not getting a minimum of 10.5 volts, the computer basically shuts down. It may not be the cause, but it is sure worth check into before spending any money on parts.
Customer: replied 2 years ago.
I noticed the lights behind the gauges would fluctuate in brightness. I also noticed the ventilation fan (a/c) noise would also fluctuate. I remember the battery light coming on when the rpm's started to drop. I will have them look at the alternator. I also saw on other blogs that leaking oil from the power steering can cause problems with the alternator. The mechanic did not mention anything about a power steering leak.
Expert:  Toyota Service replied 2 years ago.
Now that you mention these other issues I am highly inclined to think you have an alternator issue. The alternator needs to be fully checked, as in what we call a full load test. Not just measuring voltage. It needs to develop a specific amount of amperage as well as maintaining a constant 14.4 volt DC output.
Customer: replied 2 years ago.
I dropped the car off Thursday night at the mechanic's garage; however, he was gone Friday and the weekend to attend a wedding in Detroit. He contacted me today to tell me he tested the alternator (as per your suggestion) and everything came out fine with its output. He said he drove it around (short trips) without any problems and he was going to look into the problem today. (Remember: It gave me problems after driving it various places from 9:00 AM to 12:30 PM. After sitting for about an hour, I had trouble keeping it running). Do you have any other suggestions?
Expert:  Toyota Service replied 2 years ago.
I'd be interested in knowing the output voltage and the maximum amperage output of the alternator.

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