Does DFM cause lifter failure?

In vehicles with active fuel management (AFM) or dynamic fuel management (DFM), lifters collapse when the cylinder is deactivated so that the camshaft cannot open the valve when it’s not in use, preventing some cylinders from consuming fuel when only some of the engine power is needed.

Is dynamic fuel management better than active fuel management?

A few years ago, General Motors engineers created a new engine technology called Dynamic Fuel Management (DFM). This was created to be an improvement over Active Fuel Management (AFM). DFM is an engine feature that shuts down some of the cylinders to improve efficiency when the full engine power is not needed.

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What is the problem with active fuel management?

AFM lifters are known to fail more frequently than non-AFM lifters. Additionally, the system leads to excessive oil consumption. The excessive oil consumption can lead to oil levels running low, pressure dropping, and various major components such as the timing chain failing.

Does DFM cause lifter failure? – Related Questions

Will turning off AFM stop oil consumption?

When you eliminate the AFM system, the extra oil is no longer needed. Excess oil will be pushed out of the pressure relief valve into the oil pan. This will spray oil on the bottom of the cylinder walls which can cause oil burning, especially in high-rpm engines.

Does disabling AFM improve MPG?

Additionally, if you happen to spend all of your driving time in the range where the factor AFM V4 mode is the most efficient (and the V8 disabler turns it off), you will see an additional hit to the mileage (usually around 1 mpg).

Does AFM hurt engine?

What year did GM stop using AFM?

General Motors employs a number of different technologies to boost fuel economy, but one of these technologies, namely Active Fuel Management (AFM), has nearly been phased out from the 2022 Silverado engine lineup.

What causes AFM failure?

Oil pressure issues, oil quality issues, and simply running out of oil can all be causes of problems with your AFM. The best and most simple way to prevent AFM lifter failure is to check your oil regularly; ensure that it is full enough, and conduct an oil change if it’s not.

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Does GM still use active fuel management?

Note: Beginning in March 2021, most 2021 Silverado 1500 and 2021 Sierra 1500 pickups equipped with L82 MYC 6-speed and L84 MQE 8-Speed will be produced without Active Fuel Management/AFM (L82), or Dynamic Fuel Management/DFM (L84).

How much fuel does DFM save?

DFM in GM engines can shut down any number of cylinders, following 17 different patterns, depending on driving conditions and throttle input. The system helps GM’s OHV 6.2L V-8 achieve a 2-mpg (0.9 km/L) gain in real-world fuel efficiency without sacrificing any of the engine’s 420 hp and 460 lb.

How do I know if I have DFM?

You’ll know when you have DFM feedback for a part based on the yellow badge that pops up on your CAD preview, and by the yellow warning above your quote.

What cylinders shut off with AFM?

AFM (Active Fuel Management)

To provide maximum fuel economy under light load driving conditions, the engine control module (ECM) will command the cylinder deactivation system ON to deactivate engine cylinders 1, 7, 6, and 4, switching to a V4 mode.

How much fuel does AFM save?

Enhanced Fuel Economy

Range AFM Plus works with your factory installed AFM allowing your vehicle to drive in V4 mode up to 80% of the time, maximizing your fuel and dollar savings. The average driver can save approximately 65 gallons of gas per year or about $250.

Can AFM cause cylinder misfire?


If an AFM lifter is mechanically collapsed/stuck, low compression will be found on that cylinder during an AFM compression test, along with a consistent valve train tick noise, SES light, DTC P0300 and engine misfires on the related cylinder.

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What happens when you disable AFM?

An AFM Disabler is an electronic device that plugs into the OBD-II port, under the dashboard. It prevents the computer from switching over to four-cylinder mode. It’s a simple and effective way to turn off the AFM system and provides the added bonus of improving exhaust sound.

Will turning off AFM void warranty?

Because no tuning is involved with your vehicle’s computer, this product will not void the factory warranty. Not only does the AFM Disabler keep your vehicle running smoothly, but it will also have you running on all cylinders, all the time.

Does AFM cause lifter failure?

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