I think my AFM starting to go out

I had an oil change at a chain shop lets just say they forgot to tighten the filter and bolt correctly was only hand tighten

most of it leaked out lost about 4 quarts over 4 hours, since then it has had a loud clacking sound on a cold start noticeable from inside the cabin..


this is the second time it happen (getting stuck in v4 mode) when accelerating it should have been in V8 based on my RPM it was at 1500rpm (that is "accelerating" ) based on this will it need a rebuild? I have smog next year due in Jan 2021... the shops insurance accepted liability. but I still have not head from them since last month..(Dec)...

The shop also did this to another car, I was not the only victim..

 

Start looking for a newer engine.

 

Is it showing V4 on the dash? In my experience one of the valve sticks and that's the tapping you hear with the AFM. If it ran without it it could be a stuck valve but it could be a lot worse. If it's coming from the top end pull the valve cover and crank it up to see if one is sticking.

 

The oil pressure has to be turned ON to the deactivating lifters. Low pressure or no pressure in activation ports returns to V8

FYI

 

So if it's low on oil you will be running all 8 cylinders? That God to know next time someone asks how to deactivate AFM. 😂

 

Yes. There is a 5-wire connector to the manifold in the engine valley that controls the deactivation. 2-modes exit V4 before idle and Auto-Stop

 

yeah it was in v4 upon an acceleration this is a 55MPH zone so i gotta get it up there,

oil level is good and oil is clean... I change it every 4000-4800 miles

 

Have you tried turning on the heater while it is in V4 mode to see if it forces it to work on all 8 cylinders as you detailed in your hidden AFM disable switch post at the Yukon Tahoe Forum?

 

https://www.youtube.com/playlist?lis...sSBAZ_t3V4iwt-

Not affiliated with this guy but he has a great method for freeing stuck AFM lifters as cheap as possible and other good AFM knowledge to share.

 

it happened again yesterday then was a bit rough between v8/v4 for a little bit

engine oil is clean and full still at 2k miles into the oil change


it worked perfectly fine tell that point
physically undetectable v4/v8/v4 shifts

definitely a mechanical issue
cheap as possible, no the shop will have to pay to have it repaired correctly as they caused the damage.. only using new genuine GM parts
none of this after market bs I prefer them to use the same engine though(i don't want someone else garbage that burns oil,this one does not burn oil) the crank shaft might be damaged as well. ( very faint knocking on start up)...