Failing lifter?

[bcbickers]

Greetings All,

My new-to-me 2012 Suburban Z-71 started idling rough and missing this past weekend. With 151k on the clock and the last tune-up done at 75k, I figured it was time for a tune up and swapped in new AC Delco plugs and wires. The hiccup/miss actually got a bit worse and eventually threw a P0306. I thought maybe a bad wire, so I swapped the plug wires between #4 and #6, reset the codes, and drove around. No new codes after 50 or so miles and a 15 minute idle session in the driveway, but now I hear what I think is a lifter tick. It seems to run fine and make no noise or stumble when cold or at speed (oil pressure above 40 psi) but shudders/misses at lower speeds. Do I have a failed or failing lifter? See video.

 

[bcbickers]

Just realized I was in the Performance forum and not the Engine forum. Was researching fixing the 5.3 vs swapping in an L96 or LS3 just in case.

Mods, please move if needed. Thanks, and my apologies again for posting in the wrong forum.

 

[iamdub]

Greetings All,

My new-to-me 2012 Suburban Z-71 started idling rough and missing this past weekend. With 151k on the clock and the last tune-up done at 75k, I figured it was time for a tune up and swapped in new AC Delco plugs and wires. The hiccup/miss actually got a bit worse and eventually threw a P0306. I thought maybe a bad wire, so I swapped the plug wires between #4 and #6, reset the codes, and drove around. No new codes after 50 or so miles and a 15 minute idle session in the driveway, but now I hear what I think is a lifter tick. It seems to run fine and make no noise or stumble when cold or at speed (oil pressure above 40 psi) but shudders/misses at lower speeds. Do I have a failed or failing lifter? See video.

It could just be the camera mic, but it doesn't sound like a lifter to me. Sounds more like an intermittent spark arcing. Are you sure the wires are fully snapped into place? Are you sure the plugs and wires you installed are truly AC Delco? Are they AC Delco OE, Professional, Advantage, GM Genuine, Gold or Silver? Where did you get them?

 

[Miami-Dade]

@bcbickers Moved thread over here. You will get more help here.

 

[tom3]

Loose plug?

 

[bcbickers]

It could just be the camera mic, but it doesn't sound like a lifter to me. Sounds more like an intermittent spark arcing. Are you sure the wires are fully snapped into place? Are you sure the plugs and wires you installed are truly AC Delco? Are they AC Delco OE, Professional, Advantage, GM Genuine, Gold or Silver? Where did you get them?

AC Delco OE, I think. Wires are 748UU, and plugs are 41162 gapped at .040 (checked with a tool). All bought them from Rock Auto. I did a run through after swapping everything in, but I can certainly recheck everything. And that is exactly what it feels like: spark being blown out every so often or maybe a bad wire. I'll pull everything again and triple-check.

 

[Trey Hardy]

AC Delco OE, I think. Wires are 748UU, and plugs are 41162 gapped at .040 (checked with a tool). All bought them from Rock Auto. I did a run through after swapping everything in, but I can certainly recheck everything. And that is exactly what it feels like: spark being blown out every so often or maybe a bad wire. I'll pull everything again and triple-check.

What gas do you run in it? I know I thought I had a rod knock for awhile before a old mechanic asked me if I ran that “cheap gas” he said to throw some B12 or marvel mystery oil in the gas if I run the cheap stuff to prevent spark knock…
I also had a lifter stick I used a quart of marvel and 10w40 synthetic oil to help get it “free” and I’ve been doing this for about 100,000 miles almost now with good luck.
This is just a bandaid obviously
My lifter tap sounded far worse then the video you posted

 

[Trey Hardy]

Sounds like spark knock to me but I could be wrong.

 

[iamdub]

AC Delco OE, I think. Wires are 748UU, and plugs are 41162 gapped at .040 (checked with a tool). All bought them from Rock Auto. I did a run through after swapping everything in, but I can certainly recheck everything. And that is exactly what it feels like: spark being blown out every so often or maybe a bad wire. I'll pull everything again and triple-check.

RA should (still) be a reliable source for genuine parts, so you should be good there. Good on you for confirming the gap. The LS wires, with that heat shield, can be tricky to know if they're fully clicked into place. It'd be an easy item to check. I hold them by the rubber boot and twist them at least one full turn while pushing in to ensure they're fully seated, then I plug in the coil side.

Trey's comment on spark knock is a good suggestion. Did you get gas right before this all started? Maybe that station had bad fuel. I'd try his suggestion or maybe some octane booster. Maybe top off with some premium if you've burned any considerable amount out of that tank.

 

[bcbickers]

RA should (still) be a reliable source for genuine parts, so you should be good there. Good on you for confirming the gap. The LS wires, with that heat shield, can be tricky to know if they're fully clicked into place. It'd be an easy item to check. I hold them by the rubber boot and twist them at least one full turn while pushing in to ensure they're fully seated, then I plug in the coil side.

The wires I got from Rock Auto don't have the metal shields and springs. They are just a standard rubber boot. See the pic below. I will definitely recheck all of the plugs and wires this afternoon. Worth the effort before I rebuild the engine.

Trey's comment on spark knock is a good suggestion. Did you get gas right before this all started? Maybe that station had bad fuel. I'd try his suggestion or maybe some octane booster. Maybe top off with some premium if you've burned any considerable amount out of that tank.

I don't think it is gas related because I filled up at a couple of different locations in different cities this past weekend. I drove to my family's ranch on Saturday (350 mile round trip), and it started acting up on that trip. Gas mileage was 14 mpg mostly 90% freeway running 70-75 mph.

 

[bcbickers]

Impatience got the better of me, so I went out at lunch, checked the plugs, and reseated all of the wires (benefit of working from home, and may I say...that #8 plug location suuuucks). Went for a drive and all appeared well....until six or eight minutes later when the oil warmed up and the pressure dropped to around 30 psi. Then the stumble and tick came back. Once I start driving and the oil pressure comes up to 40 psi, the stumble and noise go away. When I stop again and the pressure drops to 25-30, the stumble and tick come back. So, it looks like a bad or going bad lifter.

Anyways, thanks to all of you for your help, input, and advice.

Now I need to figure out next steps. Do I delete the AFM and cam the 5.3 or swap in a L96 6.0L? Decisions, decisions...

 

[blackelky]

Impatience got the better of me, so I went out at lunch, checked the plugs, and reseated all of the wires (benefit of working from home, and may I say...that #8 plug location suuuucks). Went for a drive and all appeared well....until six or eight minutes later when the oil warmed up and the pressure dropped to around 30 psi. Then the stumble and tick came back. Once I start driving and the oil pressure comes up to 40 psi, the stumble and noise go away. When I stop again and the pressure drops to 25-30, the stumble and tick come back. So, it looks like a bad or going bad lifter.

Anyways, thanks to all of you for your help, input, and advice.

Now I need to figure out next steps. Do I delete the AFM and cam the 5.3 or swap in a L96 6.0L? Decisions, decisions...

Very exspensive questions hahaha

 

[iamdub]

The wires I got from Rock Auto don't have the metal shields and springs. They are just a standard rubber boot. See the pic below. I will definitely recheck all of the plugs and wires this afternoon. Worth the effort before I rebuild the engine.

View attachment 416983

Ah. Some part numbers for OE wires come with new shields. You're supposed to transfer your originals over. Not a big deal to run without 'em.

I don't think it is gas related because I filled up at a couple of different locations in different cities this past weekend. I drove to my family's ranch on Saturday (350 mile round trip), and it started acting up on that trip. Gas mileage was 14 mpg mostly 90% freeway running 70-75 mph.

Dammit. Well, there goes one easy fix.

 

[iamdub]

Impatience got the better of me, so I went out at lunch, checked the plugs, and reseated all of the wires (benefit of working from home, and may I say...that #8 plug location suuuucks). Went for a drive and all appeared well....until six or eight minutes later when the oil warmed up and the pressure dropped to around 30 psi. Then the stumble and tick came back. Once I start driving and the oil pressure comes up to 40 psi, the stumble and noise go away. When I stop again and the pressure drops to 25-30, the stumble and tick come back. So, it looks like a bad or going bad lifter.

Anyways, thanks to all of you for your help, input, and advice.

Now I need to figure out next steps. Do I delete the AFM and cam the 5.3 or swap in a L96 6.0L? Decisions, decisions...

Oof. Yeah, this sounds like a valvetrain issue now. IMO, if you're wanting a 6.0, start looking around. Houston is a strong market for engines of all types. You can swap it in and flash the appropriate tune and be done in a weekend. Replace that torque converter with an upgraded one while you have the engine out.

Or, you can cam the 5.3 and have the same or more power than the 6.0. You'd have to be wise with your cam choice, though. For a Z71 that might do offroad ranch duties, I'd go with the 6.0 and a torquey cam.

 

[iamdub]

Very exspensive questions hahaha

Not for us! It's easy to spend OPM.

 

[blackelky]

Not for us! It's easy to spend OPM.

Facts. I'm doing a projector retrofit because i hate halogen lights. Why they put halogen lights in 50k+ suv when new is beyond me. My 2009 lexus has hids and this 2013 doesn't.

 

[Marky Dissod]

... need to figure out next steps.
Do I delete the AFM and cam the 5.3L ...
... or swap in a 6.0L L96?
Decisions, decisions ...

Best bang-for-the-buck: 6.0L L96.
Although I suppose it would depend on what kind of cam you decide on for the 5.3L?
Keep in mind that nearly all of our engines spend nearly all of their lifetimes UNDER 2500RpM; that's where I'd want more oumpf.

 

[blackelky]

Best bang-for-the-buck: 6.0L L96.
Although I suppose it would depend on what kind of cam you decide on for the 5.3L?
Keep in mind that nearly all of our engines spend nearly all of their lifetimes UNDER 2500RpM; that's where I'd want more oumpf.

Powertrain tv did a great budget 5.3 build

 

[dkmoneypit]

Unfortunately, I got a set of AC Delco wires for my 09 Yukon and 1 of the wires was bad. Decided to do a resistance test before I got to #8 cylinder and found a bad wire. Purchased from the AC Delco store on Amazon. Check your new parts if you can.

 

[Marky Dissod]

Amazon will get worse, before it gets better ...