Mercedes-Benz has long been synonymous with luxury and performance, and their M272 and M273 engines have played a significant role in delivering on these promises. However, like any complex piece of machinery, these engines are not immune to issues, and one of the areas prone to problems is the intake manifold. In this article, we'll explore some of the common issues with the intake manifold on these engines and discuss troubleshooting and repair options.
Understanding the Intake Manifold
Before diving into the issues, let's briefly understand the role of the intake manifold. It's a critical component responsible for delivering air to the engine cylinders. In modern engines like the M272 and M273, the intake manifold is often made of plastic or composite materials for weight reduction and better thermal insulation.
Common Issues
Intake Manifold Runner Control (IMRC) Failure: The M272 and M273 engines are equipped with variable-length intake manifolds to optimize airflow at different engine speeds. These systems use flaps or runners controlled by an actuator. Over time, the plastic linkages on the manifold that control the flaps can break causing these flaps to not function, limiting your engine performance depending on the position of the flap when the linkage breaks.
Vacuum Leaks: The intake manifold is subjected to significant vacuum pressure during engine operation. Over time, the plastic or rubber components can deteriorate, leading to vacuum leaks. These leaks can cause rough idling, poor fuel economy, and illuminated check engine lights (CEL).
Troubleshooting and Repair
Diagnostic Scanning: When facing intake manifold issues, the first step is often to perform a diagnostic scan using a Mercedes-Benz diagnostic tool. This can help identify specific fault codes related to the intake manifold or associated components.
Broken Flap Linkage Codes | Intake Vacuum Leak Codes |
P2004: Tumble Flaps Stuck In Actuated Position | P0171: Fuel System Too Lean (Bank 1) |
P2005: Mechanical Fault of One Actuating Lever | P0174: Fuel System Too Lean (Bank 2) |
P2006: Stuck in Non-Actuated Position |
Performance Issues: If your intake manifold is not operating as it should, you will notice performance issues with your M272 and M273 engines such as a poor or choppy idle, and loss of power when accelerating. If you notice these symptoms when driving your Mercedes, we recommend taking it to a shop to have it inspected to avoid possible engine damage.
Replacement: The best solution if you are experiencing issues related to the intake manifold on your M272 and M273 engines is complete replacement. While it is common for owners to repair the manifold with upgraded metal linkages for the the air flap adjusters, it is labor intensive to remove the intake manifold and this repair doesn't guarantee longevity due to other fail points. If you are going through the process of removing the intake manifold, we recommended replacing it entirely to ensure you don't have to repeat the job again down the road.
Conclusion
While the intake manifold issues on Mercedes-Benz M272 and M273 engines can be frustrating, they are manageable with proper diagnosis and repair. By understanding the common issues, performing preventative maintenance, and addressing problems promptly, owners can keep their engines running smoothly and enjoy the performance and luxury Mercedes-Benz is known for.
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