㉦Mercedes KE-Jetronic㉦ - 📚🗒🩺❓How to achieve steady idle❓🩺🗒📚

Summary

In this detailed guide, the speaker discusses how to achieve a steady idle in a Mercedes by ensuring the idle control valve (ICV) functions correctly. The process includes checking various engine components, from ignition to fuel delivery systems, and diagnosing ICV issues based on engine behavior. The speaker explains how to clean and reinstall the ICV, providing practical tips for maintenance. They also emphasize using a duty cycle-capable multimeter for accurate measurements. With a mix of technical insights and light humor, the video is both informative and engaging for Mercedes enthusiasts.

Takeaways

• 😀 Start by ensuring the ignition system is fully operational for steady idle performance.
• 😀 The idle control valve (ICV) is the final step to achieving steady idle, but it's only effective if other components are working well.
• 😀 The fuel system must maintain pressure, with a functional fuel pressure regulator, injectors, and fuel distributor.
• 😀 Ensure the sensor plate isn't rubbing against its housing to avoid issues with idle stability.
• 😀 Regular maintenance is needed for the throttle lever, including cleaning and lubricating pivot points to ensure smooth operation.
• 😀 The micro switch on the throttle lever should trigger correctly, indicating idle status to the ECU.
• 😀 Airflow should bypass the throttle when idle, going through the breather hose and then to the ICV.
• 😀 The ICV must maintain a constant idle, adjusting for both cold and warm engine conditions.
• 😀 To check if your ICV is malfunctioning, monitor RPM behavior on a cold start—if RPM stays high (1200) or fluctuates improperly, the ICV may be faulty.
• 😀 If the engine stalls when turning the steering wheel or shifting into Drive, the ICV is likely the issue and can often be cleaned instead of replaced.

Q & A

What is the main topic of the video?

The main topic of the video is about achieving a steady idle in a Mercedes vehicle, specifically focusing on the idle control valve (ICV) and how it affects idle performance.

Why is the idle control valve (ICV) important for achieving steady idle?

The ICV plays a crucial role in maintaining a constant idle by controlling the air entering the engine when the throttle is fully closed. A functional ICV is essential for steady idle performance, especially when the engine is both cold and warm.

What should be checked before focusing on the ICV?

Before addressing the ICV, several other components need to be fully operational, including the ignition system, fuel pump, fuel pressure regulator, injectors, fuel distributor, sensor plate, and various sensors like the O2 sensor and potentiometer.

How does the throttle lever impact idle control?

The throttle lever can become clogged over time with dirt, affecting its movement. Lubricating its pivot points ensures smooth operation and proper interaction with components like the micro switch, which signals the ECU that the car is on idle.

How does the idle control valve (ICV) function in relation to the airflow meter?

When the throttle is fully closed, air bypasses the throttle and flows through a second hole into the ICV. The ICV adjusts the airflow, helping to maintain a constant idle by regulating the amount of air entering the engine.

How can you tell if the ICV is malfunctioning?

Signs that the ICV is malfunctioning include a steady idle above the normal range (e.g., 1200 RPM), or if the engine stalls when turning the steering wheel fully to the left or right, or when shifting into 'D' on an automatic transmission.

Can the ICV be repaired instead of replaced?

Yes, the ICV can often be cleaned and repaired. Disconnecting the hoses and soaking the ICV in diesel fuel for several hours can help clean it. Afterward, you can use a carb cleaner to finish the cleaning process.

How should you clean the ICV without damaging it?

When cleaning the ICV, never spray carb cleaner directly into the mechanism. Always spray it in a way that avoids getting cleaner inside the valve. It's important to handle the ICV carefully to prevent any damage.

What is the importance of using a duty cycle capable multimeter for testing the engine's oscillations?

A duty cycle capable multimeter is essential for accurately measuring the engine's oscillations. The ideal oscillations should be between 45-55%, as indicated on a sticker under the hood. Using the wrong equipment, like a common multimeter, may not provide accurate readings.

What should you do if the engine’s oscillations are not within the proper range?

If the engine's oscillations are outside the acceptable range (e.g., not oscillating or fluctuating too much), there may be an issue somewhere in the engine management system that requires further investigation.