HELP! 2014 e3504w Rough idle???(Dashboard pointer jitter between -/+50 rpm）
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E-CLASS
HELP! 2014 e3504w Rough idle???(Dashboard pointer jitter between -/+50 rpm）
I just bought an E-class. I am troubled by this problem and don't know what the consequences will be. There are very few results on Google. My mechanic did not find a way to solve this problem and there is no fault code displayed. The driving condition of the vehicle is very good, at least I did not feel any power attenuation.
But when I turn on the air conditioner or after my ECO start/stop is activated (the engine is re-ignited), my dashboard pointer will start to twitch in the range of +/-50 rpm.
I hope you can understand. I have tried very hard to express it, but English is not my first language.
Thanks!!!!
But when I turn on the air conditioner or after my ECO start/stop is activated (the engine is re-ignited), my dashboard pointer will start to twitch in the range of +/-50 rpm.
I hope you can understand. I have tried very hard to express it, but English is not my first language.
Thanks!!!!
Thread Starter
Newbie
Joined: Aug 2021
Posts: 4
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E-CLASS
According to my observation today, this problem has never appeared during driving. It only appears when a cold car starts. After reaching normal operating temperature, this phenomenon occasionally occurs when parking and waiting for traffic lights. This kind of convulsion will almost certainly occur when the ECO start and stop described above and the air conditioner are turned on.
When idling at 550rpm, there will be twitching of the rpm pointer on the dashboard, just like the jump of an electrocardiogram, but it is irregular, and the range of twitching is about 575-525 rpm.
At normal temperature, I did not feel an abnormality from the engine speed. It is only displayed on the dashboard.
Some details of cold car start at idling: the engine will be below 1500rpm and above 1000rpm during ignition, and will drop below 1000rpm within 1-2 seconds. During this process, the engine is very noisy. After that, the noise of the engine is significantly reduced (it feels back to normal), the engine will stay at 800rpm for a period of time, and the speed may gradually rise a little but not exceed 900rpm. Finally, the rpm slowly drops to 550 rpm at a constant speed (the idling speed is also 550 rpm when the temperature is normal). The engine is very smooth and quiet at this time and there is no body shake. The whole process takes about 10-20s in total.
No OBD2 code is displayed, and all electrical appliances are working properly.
If my description is too complicated, I can try how to upload a video here.
When idling at 550rpm, there will be twitching of the rpm pointer on the dashboard, just like the jump of an electrocardiogram, but it is irregular, and the range of twitching is about 575-525 rpm.
At normal temperature, I did not feel an abnormality from the engine speed. It is only displayed on the dashboard.
Some details of cold car start at idling: the engine will be below 1500rpm and above 1000rpm during ignition, and will drop below 1000rpm within 1-2 seconds. During this process, the engine is very noisy. After that, the noise of the engine is significantly reduced (it feels back to normal), the engine will stay at 800rpm for a period of time, and the speed may gradually rise a little but not exceed 900rpm. Finally, the rpm slowly drops to 550 rpm at a constant speed (the idling speed is also 550 rpm when the temperature is normal). The engine is very smooth and quiet at this time and there is no body shake. The whole process takes about 10-20s in total.
No OBD2 code is displayed, and all electrical appliances are working properly.
If my description is too complicated, I can try how to upload a video here.
Thread Starter
Newbie
Joined: Aug 2021
Posts: 4
Likes: 0
E-CLASS
When idling at 550rpm, there will be twitching of the rpm pointer on the dashboard, just like the jump of an electrocardiogram, but it is irregular, and the range of twitching is about 575-525 rpm.
At normal temperature, I did not feel an abnormality from the engine speed. It is only displayed on the dashboard.
Some details of cold car start at idling: the engine will be below 1500rpm and above 1000rpm during ignition, and will drop below 1000rpm within 1-2 seconds. During this process, the engine is very noisy. After that, the noise of the engine is significantly reduced (it feels back to normal), the engine will stay at 800rpm for a period of time, and the speed may gradually rise a little but not exceed 900rpm. Finally, the rpm slowly drops to 550 rpm at a constant speed (the idling speed is also 550 rpm when the temperature is normal). The engine is very smooth and quiet at this time and there is no body shake. The whole process takes about 10-20s in total.
No fault code is displayed, and all electrical appliances are working properly.
If my description is too complicated, I can try how to upload a video here.
