Are you having trouble with your vehicle’s Active Fuel Management (AFM) lifters? If so, this blog post is for you! In it, we’ll be diving into common AFM lifter failure symptoms and how to fix them.
We’ll explain what could be causing the problem in the first place, as well as any steps that can help address the issue.
From understanding warning signs of impending AFM lifter failure to tips on dealing with existing damage, this blog post will cover it all. So stick around and get ready to learn everything there is to know about protecting your engine from AFM-related problems.
What Is An AFM Lifter?
The AFM lifter (Active Fuel Management) is a feature used by the GM family of engines to conserve fuel by shutting off half of its 8 cylinders when only light engine loads are needed. When the need for more power arises, all 8 cylinders become available. This type of cylinder deactivation helps increase vehicle efficiency and reduce emissions.
How Does AFM Work?
Active Fuel Management (AFM) employs a special set of valve lifters that are used in place of half the traditional ones found in certain V6 and V8 engines. The Valve Lifter Oil Manifold (VLOM) assembly sends signals to the ECU when engine operation is light. These signals make the solenoids in the AFM lifters open, letting oil pressure into them.
This closes the interior body pins so that the valves stay closed and no fuel or air gets into these cylinders, stopping power output. At this time, only the con-rod connecting pistons with crankshafts remains active, while the AFM deactivates only valves instead of the pistons themselves.
Also Read: 7 Bad Rear Differential Symptoms (And How to Fix)
What Are The Symptoms Of AFM Lifter Failure?
Identifying an AFM lifter failure as soon as possible is critical because it can seriously harm your car. As AFM/DFM vehicles alternate between operating on half and full cylinders, some customers report feeling a “shuddering” sensation.
Costly future repairs may result from GM’s problematic valve lifters’ continual activation and deactivation over time. The following are some signs of an AFM lifter’s failure:
1. Downshifting Problems
If you’re experiencing difficulty downshifting while driving, it could be a sign that your car’s AFM lifters are broken. You must act without delay to avoid causing damage to major components of your vehicle, such as the clutch, flywheel and possibly even the gearbox system.
2. Reduced Engine Power
If the AFM lifters fail, it can also lead to a decrease in engine power. This means that your car may no longer be able to reach its full potential, and you could experience decreased acceleration or slower response time when attempting to accelerate quickly or climb hills.
The engine may also feel sluggish and unresponsive, indicating that the lifters have failed and are not properly activating your cylinders.
3. Engine and transmission Shudder
The failure of an AFM lifter can lead to engine and transmission “shuddering,” a phenomenon that occurs when the lifters fail to completely deactivate certain cylinders.
This unbalanced operation of the engine causes vibrations throughout the vehicle, particularly at idle or low speeds, resulting in a shaking sensation for drivers.
4. Vehicle Hesitation on Acceleration
If your vehicle exhibits any signs of hesitation when you press down on the accelerator, it may be indicative of a failing AFM lifter.
This could also signal other issues, such as an elevated temperature in the car or broken mass airflow sensors. In any case, never ignore this issue and have it looked at by a professional immediately.
5. Sudden Stalling
AFM lifters can sometimes malfunction and lead to the engine suddenly stalling, which can be particularly dangerous when traveling at high speeds or in congested areas. A failure of the AFM lifter to switch on or off cylinders causes the engine to abruptly cease operations, creating a hazardous situation.
Causes of AFM Lifter Failures
You should be aware of the causes of Active Fuel Management lifter failure in addition to the signs, and also how it might result in a possible hazard on the road if not addressed. The following are some issues that have been noted:
1. Low Oil Levels
One of the most common reasons for Active Fuel Management (AFM) lifter failure is an oil level that’s too low. AFM utilizes a system of valves and solenoids to shut off half the cylinders in order to conserve fuel during certain driving conditions.
When these components are not receiving sufficient lubrication, they become more prone to wear and tear as well as premature failures, which often lead to unexpected engine shut-offs or even catastrophic damage if left unchecked.
Low levels of oil can also increase contaminant buildup within the AFM components, leading to further degradation over time, so it’s important to regularly check your vehicle fluid levels in order to keep your car running smoothly and safely.
2. Poor Quality Oil
Active Fuel Management (AFM) lifter failure can be caused by poor-quality oil. The oil that is not designed to meet the standards set out by the engine manufacturer can break down more easily, leading to lubrication being reduced or partially blocked over time due to deposits building up in the AFM lifters and related components.
The formation of sludge-like material as a result of inadequate detergent action can cause premature wear on internal parts, and lead to sticking valves, low compression in cylinders, and eventual failure of AFM lifters if left unchanged for too long.
Poor quality oil may also contain contaminants such as metal particles which could further damage engine components when entering into contact with their surfaces
3. General Wear & Tear
The general use and functioning of an engine can lead to its components experiencing slow degradation over time. If this natural process of deterioration is disregarded, then the AFM lifter itself could be in danger of malfunctioning by virtue of extensive wear and tear.
What Happens When AFM Lifters Fail?
When AFM (Active Fuel Management) lifters fail, it results in engine misfiring and a decrease in performance. The vehicle becomes very sluggish or may not power up at all, depending on the severity of the failure.
In addition to poor performance, drivers may also experience a lack of oil pressure due to debris from the failed components entering other parts of the engine system.
Ultimately, this can lead to costly repair bills as many components associated with AFM function will need replacing or repairing if significant damage has occurred.
How Do I Prevent AFM Lifter Failure?
You may do a few things to prevent AFM lifter failure and more harm to your car’s engine. They are:
1. Use High-Quality Oil in Your Vehicle
It is critical for you to use high-quality engine oil as recommended by your vehicle manufacturer and follow the recommended oil change intervals in order to prevent AFM lifter failure.
Poor quality or dirty engine oils can cause premature wear of lifters, ultimately leading to their failure.
2. Service Your Car Regularly
Regular maintenance of your vehicle is crucial for preventing AFM lifter failure. This includes performing regular oil changes, replacing the oil filter, and checking and replacing other engine components as needed. Neglecting these routine maintenance tasks can cause AFM lifters to fail prematurely.
3. Use an AFM Disabler
Another way to prevent AFM lifter failure is to use an AFM disabler. This is a device that prevents the AFM system from activating, keeping all of the engine’s cylinders functioning at all times.
While this may slightly reduce fuel efficiency, it can help to prevent lifter failure and other engine problems associated with the AFM system.
In addition to these preventative measures, there are some other things to keep in mind when it comes to AFM lifter failure. For example, using the proper octane level of fuel recommended by the manufacturer can help prevent engine damage.
Additionally, avoiding heavy acceleration and hard driving can help to reduce wear and tear on the lifters and other engine components.
How Much Does It Cost To Replace AFM Lifters?
The cost to replace AFM (Active Fuel Management) lifters can vary depending on several factors, such as the make and model of the vehicle, the severity of the damage, and the location of the repair shop.
However, on average, the cost to replace AFM lifters can range between $1,000 and $2,500. This includes the cost of parts and labor for the replacement procedure.
It is worth noting that if other engine components have also been damaged as a result of the lifter failure, the cost of repair may be even higher. To avoid these costly repairs, it is important to maintain regular maintenance on your vehicle and address any issues promptly.
Also Read: Power Steering Assist Fault (Meaning, Causes & Fixes)
Frequently Asked Questions
What happens when AFM lifters fail?
When AFM (Active Fuel Management) lifters fail, they can cause a number of problems with the engine. These include poor acceleration, rough idle, misfires, and an illuminated check engine light. This is because the faulty lifter no longer controls the closing of fuel injectors and valves properly which in turn causes erratic operation in terms of combustion timing which then leads to these other issues.
What causes a GM AFM lifter’s failure?
A GM AFM lifter can fail due to a number of causes. These include worn internal parts, debris or sludge build-up, inadequate lubrication and oil pressure, wear on the camshaft lobes causing damage to the lifters, a broken valve spring inside the affected cylinder head resulting in an inability for that cylinder’s lobe to push down against its corresponding lifter during operation. If one or more of these issues is present it will cause accelerated wear which may ultimately lead to failure of the component.
Does AFM cause engine damage?
It depends on the severity of the AFM (active fuel management) system in question. In extreme cases, if it malfunctions it can cause engine damage, but for most vehicles equipped with moderate to mild levels of active fuel management system will not necessarily cause any lasting engine damage.
How much does it cost to replace AFM lifters?
The replacement of one or plenty of lifters is an expensive and time-consuming procedure. You should typically budget between $1,000 to $2,500 if you decide to hire a professional to complete the task.
Will disabling AFM stop oil consumption?
No, disabling AFM (Active Fuel Management) will not stop oil consumption. The primary cause of oil consumption is worn piston rings or valve seals that allow engine oil to pass into the combustion chamber and burn off in the exhaust gases. Other causes may include faulty oxygen sensors, incorrect spark plug gap settings and leaking fuel injectors/intake manifold gaskets.
How long does it take to replace lifters?
It can take anywhere from 4-8 hours to replace lifters, depending on the type of vehicle and the labor involved.
In conclusion, it’s important to note that AFM lift failure can be a serious issue. Understanding the signs and symptoms of this type of failure is key to identifying any underlying issues, as well as helping you diagnose and fix the problem correctly in order to avoid further damage or costly repairs down the road.
If you ever suspect your vehicle may have an AFM lifter fault, contact a professional mechanic for advice on how best to resolve it quickly and efficiently before things get worse.