Sounds Like Lifter Tick but Rockers All Moving

nickbeckss said:

2017 GMC Yukon 5.3L with 72k miles developed a tick very recently, noticeable sluggish performance but no check engine light. As I researched I discovered the dreaded collapsed lifter issue, read a lot, watched lots of videos and have my parts list compiled to get everything ordered. A couple things keeping me from moving forward with a lifter job…

As I worked through diagnostics I noticed a rodent had chewed into the fuel injector wiring for cylinder 2 pretty bad. Getting that fixed was a must and I read that injectors can tick so I replaced that harness but the ticking persists. One noticeable change after replacing the fuel injector harness is that when starting the engine initially idles fine, although still ticking, but slowly starts to bog down after 30-45 seconds and have a rough idle. Before the repair with the chewed wire the idle was consistent, without bogging down. I’m not sure why the repaired harness would cause that behavior?… in any case is it possible the injector wire shorting caused an injector to go bad and is it possible that might be the ticking sound?

I also checked for exhaust manifold leaks and don’t see any signs of that (no broken studs, no black soot), so I don’t think that’s the cause…

When using a stethoscope the loudest noise is on the top of the passenger side valve cover above cylinder 2 and 4 so pointing to a lifter or rocker issue.

The reason I’m looking into other possibilities besides a failed lifter is that when I remove the passenger side valve cover and start the engine all the rockers are moving which is unlike several videos I’ve seen where the rocker with the failed lifter either doesn’t move at all or has considerably less range of motion.

Would a failed lifter that’s ticking still result in the rockers having a full range of motion? Is it possible I’ve got a rocker ticking? Failed injector? something else?

Any ideas are appreciated.

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ss4chad said:

Hate to see ya on this forum with no responses so I thought I would chime in.

I'm assuming you looked over the rest of the motor for harness damage so lets assume that problem(s) is fixed.
Does your 5.3 have the DOD?

I learned a little bit of knowledge watching this and you know what they say, Knowledge is Power!!

Chad

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ss4chad said:

Doubeleive, I thought about a compression check but I don't think this would yield any results from the problem that nickbeckss mentioned. I ticking sound (in my opinion) is something light like a lifter or an exhaust leak or an injector. A Compression check leads me to think about a Rod knock which has a lower tone and a very obvious feel if you touch the motor.
The Noid test is a good idea though, O'Reilly Auto Parts rents that tester for $25 in Texas so depending on where you live will determine your cost, but you get the money back anyway so.....

Chad

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