Ticking engine after remote start hiccup

[808]

i had just fueled the truck, gone inside for a drink, and came out and remote started.  it coughed, gagged, and clanged like a few teeth off on a timing belt, but started up immediately after that.  muttered to myself "that aint good".  this isnt the first time my truck had made that lovely noise on remote start - happened maybe once or twice before but long enough ago i cant remember when with no ill or longstanding effect.

 

anyway, after remote starting it, she ran ok but developed what sounds like a lifter tick from the passenger side coupled with maybe a 10 wheel HP loss at most.  small enough of a loss that you may not notice it if you drive like grandpa.  cant hear the ticking in the cabin with the windows up at all, but its audible outside and sounds like a typical lifter tick on a GM.  my AFM has been off, running the same hypertech tune for the past 3+ years and 40k+ mi (87k on it now).  no codes, CEL, warnings etc, but did have historical misfire counts of 2 on cyl1, 1 on cyl3, and 1 on cyl6.  not a lot, but its more than zero.

 

wont be using the truck until I can figure it out when I have some time next week, but wanted to run this by the community in case im forgetting something.

-use stethoscope to probe around for noise source, seems to be coming from the valve cover on passenger side but its loud at the wheel well too, cadence of the tick seems to indicate top end issue and not bottom end

-need to check coils, plugs, and wires as they are all original.  seems arcing on the coils/wires can cause a similar noise to lifter tick.

-if noise concentrated on the rocker area, going to pull the valve cover, check and listen for abnormalities, and then remove and inspect the pushrods to see if anything is bent or broken.  i have a borescope I can put down the hole and inspect the lifter to see if there are any glaring defects.  i think I may have a bent pushrod, broken spring, or collapsed/spun lifter that isnt causing a catastrophic misfire.  really dont want to groove up the cam lobes.

 

if my truck hasnt been in 4cyl mode for years, is it possible to get the lifter to collapse on its own through remote starting?  i know others who have disabled AFM have still had lifters and camshafts gone bad, but I believe those are due to them spinning in the plastic tray thingy and not from collapsing due to v4 mode.  perhaps the valves were sticky with carbon and gunk on startup causing the pushrod to bend or break?  i dont know enough about this engine yet but it seems i'm going to get wayyyyy too familiar with it soon sadly : (

 

[SeekAndDestroy]

22 hours ago, 808 said:

anyway, after remote starting it, she ran ok but developed what sounds like a lifter tick from the passenger side  no codes, CEL, warnings etc, but did have historical misfire counts of 2 on cyl1, 1 on cyl3, and 1 on cyl6.  not a lot, but its more than zero.

-use stethoscope to probe around for noise source, seems to be coming from the valve cover on passenger side but its loud at the wheel well too, cadence of the tick seems to indicate top end issue and not bottom end really dont want to groove up the cam lobes.

 

if my truck hasnt been in 4cyl mode for years, is it possible to get the lifter to collapse on its own through remote starting?  i know others who have disabled AFM have still had lifters and camshafts gone bad, but I believe those are due to them spinning in the plastic tray thingy and not from collapsing due to v4 mode.  perhaps the valves were sticky with carbon and gunk on startup causing the pushrod to bend or break? 

 

I have a 2018 Sierra 6.2L. At 25k miles it started making that ticking noise. Almost sounds like a sewing machine. It had no codes except 1 historical misfire a few months before the noise started. Long story short, I took it to the dealer and it was a bad camshaft lobe. They replaced the lifters and cam under warranty. 

 

The AFM lifters sure can fail with AFM disabled electronically. The only way to avoid it is delete AFM mechanically.

Edited August 5, 2022 by SeekAndDestroy

[808]

Seek, what took out the CAM?  lifter collapse or spin?  

 

I found #4 exhaust pushrod bent like a dang boomerang.  Was all chewed up from slapping around in there.  The rocker looked ok so I just swapped that pushrod and a new valve cover gasket cause mine was smashed and hulked by whoever installed that.  Twenty bucks and I'm rolling again yeehaw.  Feels amazing when you were budgeting for a full delete and cam.

 

Guessing there was a sticky valve on startup when it revs high and could have boomeranged it then, any other ideas?  I don't run a catch can so I'm sure my valves look like a volcanic wasteland while the inside of my engine looks new lol.