M271 MAF readings at idle
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Newbie
Joined: Dec 2023
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W203 C200 Compressor
M271 MAF readings at idle
Hello, guys I have w203 m271 engine, so the problem is that it's running lean and I'm trying to find why. All the pcv stuff is new and almost every gasket and o ring of the intake is new, so don't think it's a vaccum leak. I smoke it once and it was a o ring at the intake manifold connecting to hose going to brake booster. And after fixing this still running lean at 8% ltft at idle and getting to 15-19% at acceleration. So at idle and operating temperature the maf is reading 3- 3.5 g/s in Drive gear, which I think is too much for this engine? I think it's the original one. Can someone with this engine tell me at idle and what's the value of the maf 😀
Last edited by andon0v; Dec 17, 2023 at 02:06 PM.
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Joined: Dec 2023
Posts: 29
Likes: 9
C-Class
Hey there, I don’t have specific data about your vehicle's MAF (Mass Air Flow) sensor readings. However, I can provide some general guidance.
In most engines, at idle, the MAF sensor reading would typically be relatively low, often ranging from 2 to 5 grams per second (g/s), though this can vary depending on the engine's displacement, condition, and the manufacturer's specifications.
Given your specific readings of 3 to 3.5 g/s at idle, it's slightly higher but might not necessarily indicate an issue if the engine is otherwise running smoothly without any noticeable symptoms of running lean (such as rough idling or misfires). However, if you're experiencing high long-term fuel trim values (LTFT) and it's consistently indicating a lean condition, it might warrant further investigation.
Here are a few considerations:
MAF Sensor Testing: Ensure your MAF sensor is functioning correctly by cleaning it (if possible, using MAF sensor cleaner) or potentially replacing it. Dirty or malfunctioning MAF sensors can cause inaccurate readings, leading to fuel mixture problems.
Check for Vacuum Leaks: Even after replacing gaskets and O-rings, there might still be a vacuum leak somewhere in the intake system. Check thoroughly for any leaks using a smoke test or other diagnostic methods.
Inspect Other Components: Evaluate the functionality of components such as the oxygen sensors, fuel pressure regulator, and even the exhaust system for any potential issues that might contribute to a lean fuel condition.
Given the complexity of the issue and your specific vehicle model, it might be helpful to consult with a professional mechanic who has experience with your W203 M271 engine. They can perform more in-depth diagnostics using specialized tools and knowledge, including a full system scanner like youcanic scanner that can read specific fault codes to pinpoint the exact issue.
Hope this helps.. Sorry for the long reply..
In most engines, at idle, the MAF sensor reading would typically be relatively low, often ranging from 2 to 5 grams per second (g/s), though this can vary depending on the engine's displacement, condition, and the manufacturer's specifications.
Given your specific readings of 3 to 3.5 g/s at idle, it's slightly higher but might not necessarily indicate an issue if the engine is otherwise running smoothly without any noticeable symptoms of running lean (such as rough idling or misfires). However, if you're experiencing high long-term fuel trim values (LTFT) and it's consistently indicating a lean condition, it might warrant further investigation.
Here are a few considerations:
MAF Sensor Testing: Ensure your MAF sensor is functioning correctly by cleaning it (if possible, using MAF sensor cleaner) or potentially replacing it. Dirty or malfunctioning MAF sensors can cause inaccurate readings, leading to fuel mixture problems.
Check for Vacuum Leaks: Even after replacing gaskets and O-rings, there might still be a vacuum leak somewhere in the intake system. Check thoroughly for any leaks using a smoke test or other diagnostic methods.
Inspect Other Components: Evaluate the functionality of components such as the oxygen sensors, fuel pressure regulator, and even the exhaust system for any potential issues that might contribute to a lean fuel condition.
Given the complexity of the issue and your specific vehicle model, it might be helpful to consult with a professional mechanic who has experience with your W203 M271 engine. They can perform more in-depth diagnostics using specialized tools and knowledge, including a full system scanner like youcanic scanner that can read specific fault codes to pinpoint the exact issue.
Hope this helps.. Sorry for the long reply..
Thread Starter
Newbie
Joined: Dec 2023
Posts: 6
Likes: 0
W203 C200 Compressor
Hey there, I don’t have specific data about your vehicle's MAF (Mass Air Flow) sensor readings. However, I can provide some general guidance.
In most engines, at idle, the MAF sensor reading would typically be relatively low, often ranging from 2 to 5 grams per second (g/s), though this can vary depending on the engine's displacement, condition, and the manufacturer's specifications.
Given your specific readings of 3 to 3.5 g/s at idle, it's slightly higher but might not necessarily indicate an issue if the engine is otherwise running smoothly without any noticeable symptoms of running lean (such as rough idling or misfires). However, if you're experiencing high long-term fuel trim values (LTFT) and it's consistently indicating a lean condition, it might warrant further investigation.
Here are a few considerations:
MAF Sensor Testing: Ensure your MAF sensor is functioning correctly by cleaning it (if possible, using MAF sensor cleaner) or potentially replacing it. Dirty or malfunctioning MAF sensors can cause inaccurate readings, leading to fuel mixture problems.
Check for Vacuum Leaks: Even after replacing gaskets and O-rings, there might still be a vacuum leak somewhere in the intake system. Check thoroughly for any leaks using a smoke test or other diagnostic methods.
Inspect Other Components: Evaluate the functionality of components such as the oxygen sensors, fuel pressure regulator, and even the exhaust system for any potential issues that might contribute to a lean fuel condition.
Given the complexity of the issue and your specific vehicle model, it might be helpful to consult with a professional mechanic who has experience with your W203 M271 engine. They can perform more in-depth diagnostics using specialized tools and knowledge, including a full system scanner like youcanic scanner that can read specific fault codes to pinpoint the exact issue.
Hope this helps.. Sorry for the long reply..
In most engines, at idle, the MAF sensor reading would typically be relatively low, often ranging from 2 to 5 grams per second (g/s), though this can vary depending on the engine's displacement, condition, and the manufacturer's specifications.
Given your specific readings of 3 to 3.5 g/s at idle, it's slightly higher but might not necessarily indicate an issue if the engine is otherwise running smoothly without any noticeable symptoms of running lean (such as rough idling or misfires). However, if you're experiencing high long-term fuel trim values (LTFT) and it's consistently indicating a lean condition, it might warrant further investigation.
Here are a few considerations:
MAF Sensor Testing: Ensure your MAF sensor is functioning correctly by cleaning it (if possible, using MAF sensor cleaner) or potentially replacing it. Dirty or malfunctioning MAF sensors can cause inaccurate readings, leading to fuel mixture problems.
Check for Vacuum Leaks: Even after replacing gaskets and O-rings, there might still be a vacuum leak somewhere in the intake system. Check thoroughly for any leaks using a smoke test or other diagnostic methods.
Inspect Other Components: Evaluate the functionality of components such as the oxygen sensors, fuel pressure regulator, and even the exhaust system for any potential issues that might contribute to a lean fuel condition.
Given the complexity of the issue and your specific vehicle model, it might be helpful to consult with a professional mechanic who has experience with your W203 M271 engine. They can perform more in-depth diagnostics using specialized tools and knowledge, including a full system scanner like youcanic scanner that can read specific fault codes to pinpoint the exact issue.
Hope this helps.. Sorry for the long reply..
