Engine problems can be frustrating, especially when they seem to come out of nowhere. For owners of vehicles, particularly those with sophisticated engine technologies like Active Fuel Management (AFM) or Dynamic Fuel Management (DFM), issues like lifter failure can be a significant concern. A common question that arises when experiencing engine trouble is: Does Obd2 Show Code For Lifters?
To address this, let’s delve into how your vehicle’s On-Board Diagnostics II (OBD2) system works and what it can tell you about potential lifter problems. We’ll also explore the symptoms of collapsed lifters and how to properly diagnose these issues.
Understanding Collapsed Lifters and Engine Misfires
Lifters, also known as valve lifters or hydraulic lifters, are critical components in your engine. They are situated between the camshaft and the valves, responsible for transmitting the motion of the camshaft to open and close the engine valves. This precise action is essential for the combustion process within each cylinder.
When a lifter collapses, it means it has failed to maintain proper hydraulic pressure. This can happen due to wear, contamination, or component failure within the lifter itself. A collapsed lifter can lead to a valve not opening or closing correctly, resulting in a range of engine problems, most notably a misfire.
A misfire occurs when one or more cylinders in your engine fail to ignite the air-fuel mixture properly. This can be due to various reasons, including issues with spark plugs, fuel injectors, or, as in our focus, valve train problems caused by faulty lifters.
Can OBD2 Scanners Detect Lifter Issues?
Now, back to the primary question: Does OBD2 show code for lifters? The direct answer is no, OBD2 scanners do not directly show a code specifically for “lifter failure.” OBD2 systems are designed to monitor a wide array of engine and emissions-related parameters, but they operate at a higher level of system monitoring. They are excellent at detecting the symptoms of a problem, but not always the precise root cause component.
In the case of collapsed lifters, the most common symptom that an OBD2 system will detect is a cylinder misfire. The engine control module (ECM) monitors the crankshaft speed. When a misfire occurs in a cylinder, it causes a momentary fluctuation in crankshaft speed. The ECM recognizes this and sets a misfire code.
Common OBD2 codes associated with misfires include:
- P0300: Random/Multiple Cylinder Misfire Detected
- P0301 – P0308 (and higher depending on engine cylinder count): Cylinder Specific Misfire Detected (e.g., P0301 – Cylinder 1 Misfire Detected)
These codes indicate that a misfire is occurring, and they can even pinpoint which cylinder is affected. However, the OBD2 code itself will not tell you directly that the problem is a collapsed lifter. It simply indicates a misfire.
Diagnosing Collapsed Lifters: Beyond OBD2 Codes
While OBD2 codes are a crucial starting point, diagnosing collapsed lifters requires further investigation. Here’s a step-by-step diagnostic process, often employed by mechanics, which mirrors the experience described in the original forum post:
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Initial Symptoms and OBD2 Scan: The first sign is often a rough idle and potentially an illuminated check engine light. Scanning for OBD2 codes will likely reveal misfire codes (P0300, P030x).
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Ruling Out Common Misfire Causes: A systematic approach involves eliminating other common causes of misfires. This might include:
- Spark Plugs and Wires/Coils: Inspecting and replacing spark plugs is a routine maintenance step and a common first check.
- Fuel Injectors: Testing fuel injectors to ensure they are delivering fuel correctly. As seen in the original post, dealerships may initially suspect injectors.
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Compression and Leak-Down Tests: These tests assess the mechanical integrity of the cylinder. Good compression is essential for proper combustion. While the original poster’s experience mentioned “good” compression and leak-down tests initially, it’s important to note that in some cases of lifter failure, these tests might still show within acceptable ranges, especially in early stages.
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Valve Train Inspection: When misfires persist and other common causes are ruled out, the valve train becomes a prime suspect. This is where a collapsed lifter diagnosis becomes more focused. Methods to inspect the valve train include:
- Listening for Ticking Noises: A collapsed lifter can sometimes produce a noticeable ticking or tapping sound, especially at idle.
- Valve Cover Removal and Visual Inspection: Removing the valve cover allows for a visual inspection of the lifters, pushrods, and rocker arms. A collapsed lifter might show excessive play or damage.
- Using a Borescope: While the original post mentioned the dealership initially lacking the correct scope attachments, a borescope can be used to visually inspect valve components without extensive disassembly.
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Cylinder Head Removal (Definitive Diagnosis): In more complex cases, or when a definitive diagnosis is needed, cylinder head removal might be necessary. This allows for a thorough inspection of the lifters, camshaft lobes, and valve train components. As experienced by the original poster, this step revealed the collapsed lifters and camshaft damage.
Repairing Collapsed Lifters and Considering Options
Once collapsed lifters are confirmed, repair options range from replacing just the failed lifters to more comprehensive overhauls. Common repair paths include:
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Lifter Replacement: Replacing all lifters is generally recommended when one or more have failed. It’s often wise to replace the camshaft as well, especially if there is evidence of lobe wear, as seen in the original post.
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AFM/DFM Delete (If Applicable): For vehicles equipped with Active Fuel Management or Dynamic Fuel Management, which are known to sometimes contribute to lifter issues, a common upgrade during repair is to “delete” or disable this system. This often involves replacing lifters with non-AFM/DFM lifters, installing a non-AFM/DFM camshaft, and ECM tuning. This can improve long-term reliability.
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Engine Replacement: In cases of severe engine damage, or if the vehicle has high mileage and other wear and tear, engine replacement might be considered. However, as the original poster noted, even a new engine might come with the same lifter design, potentially leading to future issues if the underlying design flaw isn’t addressed.
GM Lifter Problems and Class Action Considerations
The original forum post mentions concerns about GM lifter designs, particularly in engines with AFM/DFM. There has been widespread discussion and even class action lawsuits related to lifter failures in certain GM engines. While this article focuses on diagnostics and OBD2, it’s worth noting that if you experience lifter failure in a GM vehicle, researching potential recalls, technical service bulletins (TSBs), and class-action information related to your vehicle’s year and engine is advisable.
Conclusion
Does OBD2 show code for lifters? No, not directly. However, OBD2 systems are invaluable for detecting engine misfires, which are a primary symptom of collapsed lifters. When you see misfire codes (P0300, P030x), especially accompanied by a rough idle or ticking noises, collapsed lifters should be considered as a potential cause, particularly in vehicles known to have lifter-related issues.
Accurate diagnosis requires moving beyond OBD2 codes and employing systematic troubleshooting steps, including visual inspections and potentially cylinder head removal. Understanding the limitations of OBD2 and the diagnostic process is crucial for effectively addressing engine problems like collapsed lifters and getting your vehicle back in reliable running condition.
