1UZ Engine Shutting off when temperature rises to half
#136
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Thread Starter
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third, the car should idle as follows (per service manual):
IDLE SPEED
INSPECTION
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connected
HINT:
All vacuum hoses for EGR system, etc. should be properly connected.
(f) SFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
(i) Air conditioning switched OFF
2. INSPECT IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
650 ± 50 rpm
IDLE SPEED
INSPECTION
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connected
HINT:
All vacuum hoses for EGR system, etc. should be properly connected.
(f) SFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
(i) Air conditioning switched OFF
2. INSPECT IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
650 ± 50 rpm
What could possibly explain my RPM dropping so low when the engine temperature reaches this mark?
N.B--please note that at the 40% mark of the temperature gauge, this rough idling problem and shutting off does not exist.
#138
Pole Position
Thread Starter
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Thanks Bud..Cowboy, does your recommended scan tool have the live data feature ? From your thread:
https://www.clublexus.com/forums/ls4...uld-spend.html
https://www.clublexus.com/forums/ls4...uld-spend.html
#139
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Hi MattLs400,
I had the same problem. The solution is very simple.--> Throttle body cleaning.
My problem: A/C compressor off when engine warm, because it is too low idling. A/C compressor on when runing engine.
I was thinking that we could be in trouble. Idle RPM warm-->450
Too low.
I look my throttle body. Butterfly valve is very dirty. I cleaning my throtle body, thereafter RPM 650 and A/C compressor not off.
Steps:
1. Battery negative cable take off. !!!!Very important!!!
2. Cleaning throttle body.
3. Waiting 30-40 minutes. The engine computer must forget the old/bad RPM.
4. Battery negative cable take on.
5. Automatic transmission--> "P" and running the engine.
6. Let the engine run for 30 minutes. Do not give me gas, automatic transmission olny "P" position. (This engine computer learning time)
7. Enjoy the new 650-700 RPM.![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
This repair very cheap.
I hope I could help.
I had the same problem. The solution is very simple.--> Throttle body cleaning.
My problem: A/C compressor off when engine warm, because it is too low idling. A/C compressor on when runing engine.
I was thinking that we could be in trouble. Idle RPM warm-->450
![Uhh...](https://www.clublexus.com/forums/images/smilies/1387914497.gif)
I look my throttle body. Butterfly valve is very dirty. I cleaning my throtle body, thereafter RPM 650 and A/C compressor not off.
Steps:
1. Battery negative cable take off. !!!!Very important!!!
2. Cleaning throttle body.
3. Waiting 30-40 minutes. The engine computer must forget the old/bad RPM.
4. Battery negative cable take on.
5. Automatic transmission--> "P" and running the engine.
6. Let the engine run for 30 minutes. Do not give me gas, automatic transmission olny "P" position. (This engine computer learning time)
7. Enjoy the new 650-700 RPM.
![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
This repair very cheap.
I hope I could help.
#141
Pole Position
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Hi MattLs400,
I had the same problem. The solution is very simple.--> Throttle body cleaning.
My problem: A/C compressor off when engine warm, because it is too low idling. A/C compressor on when runing engine.
I was thinking that we could be in trouble. Idle RPM warm-->450
Too low.
I look my throttle body. Butterfly valve is very dirty. I cleaning my throtle body, thereafter RPM 650 and A/C compressor not off.
Steps:
1. Battery negative cable take off. !!!!Very important!!!
2. Cleaning throttle body.
3. Waiting 30-40 minutes. The engine computer must forget the old/bad RPM.
4. Battery negative cable take on.
5. Automatic transmission--> "P" and running the engine.
6. Let the engine run for 30 minutes. Do not give me gas, automatic transmission olny "P" position. (This engine computer learning time)
7. Enjoy the new 650-700 RPM.![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
This repair very cheap.
I hope I could help.
I had the same problem. The solution is very simple.--> Throttle body cleaning.
My problem: A/C compressor off when engine warm, because it is too low idling. A/C compressor on when runing engine.
I was thinking that we could be in trouble. Idle RPM warm-->450
![Uhh...](https://www.clublexus.com/forums/images/smilies/1387914497.gif)
I look my throttle body. Butterfly valve is very dirty. I cleaning my throtle body, thereafter RPM 650 and A/C compressor not off.
Steps:
1. Battery negative cable take off. !!!!Very important!!!
2. Cleaning throttle body.
3. Waiting 30-40 minutes. The engine computer must forget the old/bad RPM.
4. Battery negative cable take on.
5. Automatic transmission--> "P" and running the engine.
6. Let the engine run for 30 minutes. Do not give me gas, automatic transmission olny "P" position. (This engine computer learning time)
7. Enjoy the new 650-700 RPM.
![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
This repair very cheap.
I hope I could help.
![Sad](https://www.clublexus.com/forums/images/smilies/sad.gif)
But, question as to why it may not be throttle body cleaning....>> The problem only happens when the Engine is warm (Half Temp)...Therefore, if it were a dirty Throttle Body/ Butterfly issue, won't the problem persist all the time, irregardless of when the engine is cold/ hot?
#142
Pole Position
Thread Starter
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Hmmmm....some good food for thought there Yamae....Thanks!
I have made videos of the problem being experienced on this car. How can I upload these videos ?
I have made videos of the problem being experienced on this car. How can I upload these videos ?
#143
Moderator
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400rpm is too low. Why don't you simply remove the IACV from the throttle body and check the air passage located at the center part of it. The attached drawing might help you. I'm sure it is badly clogged and you need to clean it.
When the car is warmed up and the IACV is almost closed but still passing thorough some air for the idle, the clogged passage limits the amount of it. This must be your situation, I bet.
At the idle, the engine needs about 50g/sec of air but the clogged passage can't pass through that much. Yours must be passing only 35g/sec or so, according to the calculation.
When the car is warmed up and the IACV is almost closed but still passing thorough some air for the idle, the clogged passage limits the amount of it. This must be your situation, I bet.
At the idle, the engine needs about 50g/sec of air but the clogged passage can't pass through that much. Yours must be passing only 35g/sec or so, according to the calculation.
#145
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Ok Guys There is another Temp sensor in the system This is right next to the Gauge sensor This one has Two wires and talks to ECU It can also be bad and If so tells the ECU the engine temp wrong info and can confuse the situation .... If it is bad and tells ECU engine is clod still it Affects Mixture ie it runs rich always and your gas mileage suffers too !!
#146
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Sensor I bought Online True Blue Auto Parts Beck?Arnley #158-0421 $23.65 Free Shipping
I renewed both these sensors as cheap Insurance to get proper info to me and the ECU
http// trueblueautoparts.com
I renewed both these sensors as cheap Insurance to get proper info to me and the ECU
http// trueblueautoparts.com
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avhart (03-18-21)
#148
Lexus Champion
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a good link to fixing a IACV for those interested.
http://planetsoarer.com/IAC/iac.htm
http://planetsoarer.com/IAC/iac.htm
if anyone needs the original correct IACV bearings brand new made in Japan - PM me
#149
Lexus Champion
#150
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Thread Starter
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L8274 I am now being informed of this. I have changed my Engine Coolant Temp Sensor to OEM 89422-20010.....Now you're telling me there's another which should have been changed ? Thats weird, I was never informed that there are 2 ECTS...Please, send me a link for this other Temp sensor and where is it located?
Members,
the following is a link to the video of the Problem I am experiencing with my 1996 Celsior (1UZ-FE)