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Discussion Starter #1
Hello~!
I own 1989 560sel
The cold start works very well, but when the cooling water gauge reaches 85-90, the engine relief starts at 4000rpm sorry when the full accelerator starts and the engine does not start immediately and does not accelerate.

If the coolant temperature is below cold ~ 60 ~ 70 ° C, acceleration is good when full accelerator and there is no problem.

The mileage is replaced by 67000km. The attached part is a green 2 pin type water temperature sensor, 2 fuel pumps, a fuel filter, a fuel pump relay, a crank position sensor rear, and an ovp relay.

Thank you in advance for your help
 

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1991 560sec. 1969 280SL
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Hard to understand what you mean, but the coolant sensor you should have replaced is the four prong round one on front middle of intake just behind the idle control valve. it has a big black round connector. That’s the one that relays the engine temperature to the ECM.
 

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1989 560SEC, 1989 560SEL, 1995 E420
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There's something about model year 1989. Our '89 SEC has the four-pin coolant temp sensor but our '89 SEL has the two-pin. Weird.

Anyway, it sounds to me like the sensor is defective or the EHA isn't working or isn't getting a signal from the ECU. When the car goes closed-loop, the ECU takes over mixture control.

What happens if you disconnect the EHA when the problem starts?
 

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Discussion Starter #4
[QUOTE = "gogi, 게시물 : 17966411, 회원 : 129122"]
이해하기 쉬운 상태를 유지해야합니다. 큰 검은 색. 실제로 엔진 온도를 ECM으로 전달하는 것입니다.
[/ 인용문]
Hard to understand what you mean, but the coolant sensor you should have replaced is the four prong round one on front middle of intake just behind the idle control valve. it has a big black round connector. That’s the one that relays the engine temperature to the ECM.
Thanks for the answer.!!
My car pic ^^;;
 

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Discussion Starter #5
[QUOTE = "gogi, 게시물 : 17966411, 회원 : 129122"]
이해하기 쉬운 상태를 유지해야합니다. 큰 검은 색. 실제로 엔진 온도를 ECM으로 전달하는 것입니다.
[/ 인용문]
There's something about model year 1989. Our '89 SEC has the four-pin coolant temp sensor but our '89 SEL has the two-pin. Weird.

Anyway, it sounds to me like the sensor is defective or the EHA isn't working or isn't getting a signal from the ECU. When the car goes closed-loop, the ECU takes over mixture control.

What happens if you disconnect the EHA when the problem starts?

Thanks for the answer.!!!!!!!

When symptoms started, the eha valve was removed, and the failure symptoms were maintained !! It was amazing !!! The same symptoms appeared immediately after removing the eha valve even when the engine was cold!
 

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1988 300CE
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Raycun46, I just have enough time to let you know what you should do first … namely a test drive with only the o2 sensor disconnected !

If the car behaves better, there is either a problem with the o2 sensor, or … albeit less likely … the CIS-ECU, or the o2 sensor wire, or the o2 sensor‘s connection to ground (via exhaust pipe → engine → ground strap).

For detailed instructions about how to check ^these (and other) things, please let other forum members help you. I‘m currently too busy for further detailed assistance.

H.D.
 

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Discussion Starter #8
Raycun46, I just have enough time to let you know what you should do first … namely a test drive with only the o2 sensor disconnected !

If the car behaves better, there is either a problem with the o2 sensor, or … albeit less likely … the CIS-ECU, or the o2 sensor wire, or the o2 sensor‘s connection to ground (via exhaust pipe → engine → ground strap).

For detailed instructions about how to check ^these (and other) things, please let other forum members help you. I‘m currently too busy for further detailed assistance.

H.D.
Thank you for your answer
I will check o2 sensor first and ground wire.
 
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