Question about the GMC 5.3 with AFM

So if you delete that, does that mean your engine runs on all 8 all the time? That would make the not so great fuel mileage worse...

I think the suburban has that. Didn't know it was a "bad" thing.

 

The idea is not bad, but in most cases (despite brand) it has unintended consequences...and the gains are generally minimal anyways.

 

Gm has had issues with the lifters collapsing and sending shavings through the engine since the amf “active fuel management” came out older ones had 4 of the 8 that could do it and later ones I think all 8 could so they could switch the deactivate cylinders around more. I think oil changes and good oil help them from issues another weak point is the oil pump that sheds the pump vanes. Ram has cam issues from oil pressure at idle and plugged passages from infrequent oil changes. Ford now has their own cylinder deactivation since 21 on the 5.0, the deactivation itself isn’t an issue I’ve heard about so far because of the dohc vvt on them it has no complicated lifter just the same style cams and phasers as before with some new programs to deactivate cylinders. Basically new programs for same system and the usual cam phaser problems that can occur. On all of the new trucks 4-5000 mile oil changes with good oil and filters vs the recommended 8-10000 definitely helps with issues.

 

Yup, and Honda has issues with burning oil on their 3.5 V6 VVT.
I don't know that any manufacturer with cylinder deactivation has a great record with it...pretty easy to disable though

 

Turning it off and deleting it is 2 different animals all together. Deleting it is changing the cam/lifters out, turning it off is one of the plug and play devices listed here and on web.

 

I run Amsoil OE 0W-20 in my Tahoe and use 10K oil change intervals. We got it with 23k on the clock, we are now at 110,000 and no issues. Oil usage is right at a half a quart in 10,000 miles.

 

My buddy tried that on his 14 ford 3.5 ecoboost, had chains replaced at around 45,000 I had the same truck basically with same engine and we both towed about the same and mine never were changed before I traded at 114,000. I used a ford or fram gold synthetic filter with fram full synthetic 5-30 changed ever 4-5000 miles and an air filter every other oil change. He did 10-12000 on amsoil signature series 5-30 in his and it needed a second set of chains at 120,000 on trade in. And I’m not saying that amsoil isnt probably the best oil made it’s just everything shears and breaks down in a turbo motor that’s also direct injection and has dilution issues along with one long timing chain with plastic guides. The 2nd gen 3.5 has twin chains and my 2.7 has always had 2 chains. Still doing 4-5000 change intervals on my 2.7 and the wife’s 2.3 ecoboost explorer with good filters and group 3 synthetic oil. Now using Mobil full synthetic because the fram full synthetic oil isn’t available here anymore. The fram was a product of conoco/phillips who also makes the ford oils so that was my reasoning for buying. Always had the latest ford turbo specs right away.

 

Toyota also had an oil burning issue, as did other manufacturers, again trying to get every .1mpg they can they reduced the ring tension and oil finds it’s way into the combustion chamber.

 

That combined with toyota's recommendation for 10k mile oil changes in those years.

 

My BIL's Chevy had a lifter collapse and started eating the cam. He caught it in time and did a full delete and tune. Runs a lot better and he said he actually gets better fuel mileage now.

I tried talking him into putty a choppy cam in it, but apparently he hates fun.

 

Hey guys,
I didn't read the whole thread but....
My 01 5.3 has 270k on it with no modifications, still runs & sounds just dandy.
What's required to get it to blow up?

I just bought an 03 with 225k that sounds like it might puke out at any moment, so maybe my 01 is the exception to the rule.

And, what's AFM?

 

AFM stands for advanced fuel management. The computer shuts down 4 cylinders during light load situations such as highway constant speed. GM uses special lifters on those 4 cylinders. These special lifters are known to collapse and wear the cam and put metal into the engine.

 

Did all early 5.3s have that "feature"?

 

Active fuel management and an 01 doesn’t have it and I don’t think the 03 will either but may be wrong

 

Looks like 05-2022, until they went direct injection.

 

Good to know.
I'll avoid those years in the future.

 

We bought an extended warranty as well, just in case the engine or transmission GM’d on us prematurely…

 

Did the same with my 2.7 ecoboost even though they are pretty reliable if you research them

 

My 2018 5.3 has afm and direct injection. No issues yet.