Another AFM issue?

g2full · October 27, 2019

So, decided to beat on my truck a little last night, which I don't do often but from time to time I do stretch its' legs a bit.

Threw a check engine light and could feel a misfire.

So, pulled codes and sure enough misfire on cylinder #7. Today I swapped plugs and wires, cleared the code and fired it back up to have the same results. Pulled codes again - cylinder #7 misfire. Swapped coil packs around and the misfire stayed on #7.

Did a compression test - just a hair under 125 on cylinder #7. I didn't check the other cylinders, at this point I'm frustrated.

New plug is oil soaked from a 10 mile drive.

No obscure noises coming from the engine. Could this be an AFM lifter issue?

I do have a Zurich powertrain and will be taking it to the dealer tomorrow. Just want some opinions from the knowledge here.

Thanks!

15 Silverado 5.3 non flex fuel motor. 78k miles on it.

Lsgun1 · October 28, 2019

Oil soaked or fuel soaked? Oil shouldn't enter a cylinder if it's a lifter issue.

g2full · October 28, 2019

7 minutes ago, Lsgun1 said:

Oil soaked or fuel soaked? Oil shouldn't enter a cylinder if it's a lifter issue.

Pretty sure oil. I mean, it smelt like raw fuel for sure. But was black and oily. Was able to sling it off the plug even.

g2full · October 28, 2019

What should I be seeing numbers wise on the compression test? I have tried searching but can't seem to find anything.

Lsgun1 · October 28, 2019

A lifter collapse would just not open a valve it wouldn't get oil in the cylinder. If oil is getting in it's potentially piston rings, valve seals or a head/head gasket problem. You're going to have to dive deeper in. I'd start looking at the injectors just since we've seen enough failures that it could just be dumping fuel in and maybe is mixing with the carbon on the tip of the plug to turn whatever liquid is in there a darker color.

Edited October 28, 2019 by Lsgun1

Slash L86 · October 28, 2019

If I ever(fingers crossed) get a ce light for engine misfire then that bitch is getting towed (assuming still under warranty or extended? )directly to the nearest dealer.

Oil on plug sounds to me (and I'm by no means qualified to even answer) like a gasket or o ring. Exhaust smoking?

I did own a 93 isuzu rodeo that had some weird issue with defective plug boot wires and some oil was in the plug area when I tuned it. Never got a ce or misfire from it though. That was a real long time ago.

With these engines and all the computer shit it could really be anything causing it.

My suggestion would be get a good (if you already don't have one) extended warranty on it and read it to see if have to wait certain time to bring it in.

Edited October 28, 2019 by Slash L86

g2full · October 28, 2019

Thanks for all the replies everyone. It's going in today as I do have a Zurich powertrain. I'll keep everyone updated on the cause for sure.

After this (depending on the outcome) if the truck is fixed I will be tuning out the AFM.

g2full · October 28, 2019

Dropped off at the dealer. They're saying they can't look at it until next week so we will see. Tech was talking with advisor when I dropped it off and he seems confident with explaining the issue and what I've already done that it's either a lifter or piston.

g2full · October 31, 2019

Dealer called back.

Failed lifter and bent push rod.

Seems that GM is picking up the bill. Writer made it seem as if it was under a warranty extension. I believe I"m still going to look to tune out the AFM.

g2full · November 1, 2019

Another update -

Truck came back today. They did 2 lifters, the solenoid valley pan thing that controls the AFM lifters, Head Gasket, Oil Change, and Push Rod.

Was speaking with the tech and he's concerned that I also have an injector failing. He said my one fuel trim is at 18% and typically he likes to see plus or minus 5% of 0.

My concerns are - injectors aren't covered under my extended warranty/powertrain. Second concern is that I just ordered my Autocal and if I have an injector issue obviously I'll need to sort that out before I get it tuned. While running in the shop it actually came down 2%(to the 18%) so maybe the truck is just un happy that everything was apart?

What is everyones thoughts and or suggestions at this point?

ksiesel · November 2, 2019

I thought I read on here that GM extended the injector coverage on the K2xx GDI injectors. I’m sure if you do a search, you’ll find something about it.

g2full · November 2, 2019

33 minutes ago, ksiesel said:

I thought I read on here that GM extended the injector coverage on the K2xx GDI injectors. I’m sure if you do a search, you’ll find something about it.

It would be awesome if they did. Thank you. I’ll look around.

bg1988 · November 2, 2019

On 10/27/2019 at 3:01 PM, g2full said:

So, decided to beat on my truck a little last night, which I don't do often but from time to time I do stretch its' legs a bit.

Threw a check engine light and could feel a misfire.

So, pulled codes and sure enough misfire on cylinder #7. Today I swapped plugs and wires, cleared the code and fired it back up to have the same results. Pulled codes again - cylinder #7 misfire. Swapped coil packs around and the misfire stayed on #7.

Did a compression test - just a hair under 125 on cylinder #7. I didn't check the other cylinders, at this point I'm frustrated.

New plug is oil soaked from a 10 mile drive.

No obscure noises coming from the engine. Could this be an AFM lifter issue?

I do have a Zurich powertrain and will be taking it to the dealer tomorrow. Just want some opinions from the knowledge here.

Thanks!

15 Silverado 5.3 non flex fuel motor. 78k miles on it.

what is the OCI for that 78k?

g2full · November 2, 2019

30 minutes ago, bg1988 said:

what is the OCI for that 78k?

Since I’ve had it at 64k 11 months time frame I’ve only done 3. Truck was actually on a fresh change when this happened.

I try to stick around 5k but I also pay attention to the maintenance minder.

bg1988 · November 2, 2019

16 minutes ago, g2full said:

Since I’ve had it at 64k 11 months time frame I’ve only done 3. Truck was actually on a fresh change when this happened.

I try to stick around 5k but I also pay attention to the maintenance minder.

5k is good you have 8qt