Why and How to Disable GM's Active Fuel Management (AFM)!

today we're going to talk about afm how to identify it how it works and how to get rid of it if it fails [Applause] [Music] active fuel management afm is a trademark general motors technology that improves gas mileage by shutting down half the cylinders under light load conditions to reduce fuel consumption it's also known as displacement on demand or cylinder deactivation afm and working properly and in the right application it's not a bad thing but when it does go badly it can create all sorts of headaches in your classic muscle car race car when you're doing your build some junkyard ls engines you may find may have had afm problems and that explains why they're in the junkyard to begin with our goal is to give you the tools and the know-how to save these engines and make them perform as they should please keep in mind some of the products used in these videos are intended for use in engine swaps and or racing applications how does the fm work when the engine load is low the computer sends a signal to the lifter oil manifold assembly otherwise known as the loma the low solenoids open and the oil runs to the lifter and collapses a plunger inside the collapsed lifters will not engage the push rods and both valves remain closed since no air can get in and out the engine is running on only four cylinders the afm cylinders are opposite of one another in the firing order they act like air springs and allow for smooth operation the latest of the gen 5 engines can shut down any of the eight cylinders in different sequences which gives the vehicle the right amount of power for different conditions as engine load increases the computer sends a signal to the loma and the solenoids close oil bleeds off the lifters and they return to normal operating condition and your engine is running on eight cylinders again say you're going through a salvage yard to find an engine but you're you know something for your old hot rod how do you identify an engine that's equipped with afm first is the valley cover the afm cover is ribbed on top with solenoids on the underside it has an electrical connector on the back and the non-afm engines all have just a smooth valley cover the second is the engine block all gen 4 engine blocks have afm towers and oil passages cast in however they are only functional on engines that used afm the third is the lifters gen 4 and early gen 5 engines use special lifters for cylinders 1 4 6 and 7. they're taller and can be identified by the springs mounted on the top engines with afm also use a special camshaft high volume oil pump and a pressure relief valve in the oil pan the fourth is the oil pressure relief valve we just talked about a bit the valve is located on the oil pan rail and prevents excessive oil pressure from negatively impacting afm components the original 2007 to 9 version sprayed oil on the cylinder walls and it increased oil consumption to fix this in 2010 gm added a deflector part number nal-12639759 to redirect it into the oil pan this can be added to your earlier model if you experience high oil consumption how does afm affect performance afm is good for gas mileage and can be five to seven percent more fuel efficient under certain conditions so why turn it off there's a few reasons many people find that the four-cylinder sound is kind of annoying if their vehicle is equipped with a louder aftermarket exhaust some drivers want v8 power under their foot at all times in higher mileage engines that haven't had the oil changed regularly the afm lifters have a history of failing and oil consumption can be a problem there are two ways to disable or delete active fuel management one is to install an afm disabler and the second is to install an afm delete kit which option is best for you a disabler or a delete kit as long as the lifter hasn't started to fail you can get by with the less expensive disabler's preventative maintenance if the lifter has already started to fail an afm delete kit is the way to go getting back to the disabler it's an electronic device that plugs into the obd2 port underneath the dashboard it prevents the computer from switching to four cylinder mode it's a simple and effective way to turn off the afm system and provides the added bonus of improving the exhaust sound what if your lifters rockers or camera already damaged the leak kit simply replaces the afm components with the standard parts when installing an afm delete kit you must upgrade to a non-afm cam because the cam lobes on the four afm cylinders are ground differently the engine will have 25 less pounds of cranking compression in those four cylinders which can result in a misfire code and now is a good time to install that big camby voice wanted engines with afm also use a high volume oil pump when you eliminate the afm system the extra oil is no longer needed excess oil will be pushed out of the pressure relief valve and this will spray on the bottom of the cylinder walls which will cause burning especially in high rpm engines so it's a little bit more work but it's recommended that you plug the pressure relief valve in the oil pan with a m14 by 1.5 millimeter pipe plug it's also recommended that you switch out to a standard volume oil pump to not throw codes you will need to turn off the afm and ecm using a computer programmer or custom tuning if you're in a situation where you've installed the afm delete kit but don't have access to a programmer a disabler can still be a viable option to do this you need to leave the afm solenoid pack connected to ensure no codes are thrown and you can reuse the original valley cover or a non-afm valley cover and leave the harness connected and just tuck the solenoid back away on the firewall summit racing has everything that you need to you know install new afm components if you want to go that direction or delete it we've got the disablers we've got the programmers just head to summitracing.com and we'll take care of you be sure to like and 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Channel: Summit Racing

Views: 639,073

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Id: GcuC2FxozE8

Length: 6min 21sec (381 seconds)

Published: Wed Apr 28 2021