Do I need to delete AFM?

[RAWVORTEC]

So if the heads have obviously been off, then we could assume the afm has been touched? But the suburban still goes into v4 mode. Is there a fix where it would retain the dual mode?


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[iamdub]

So if the heads have obviously been off, then we could assume the afm has been touched? But the suburban still goes into v4 mode. Is there a fix where it would retain the dual mode?


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The heads could have been off for a number of reasons not pertaining to AFM at all. The heads themselves could've been replaced or maybe just the gaskets were replaced. You said the guy you bought it from thought the lifters may have been replaced by the guy before him, so we could ASSUME that's why the heads were off. What you can't tell unless you track down the owner before who you bought the Suburban from is what was done when the heads were off. Maybe they just replaced a couple failed AFM lifters? Maybe they replaced all of them? Maybe they used exact originals? Maybe they used the updated lifters? Who knows?!

Whatever was replaced wasn't to disable or delete AFM as the system is still functional.

 

[donjetman]

Here is a good article about deleting DOD AFM and replacing the lifters.

https://www.enginelabs.com/news/tech-tips-replacing-ls-active-fuel-management-lifters-with-melling/