Cylinder #4 Misfire after replacing a collapsed lifter?

Tiny
DARKFREELIFE
  • MEMBER
  • 2010 CADILLAC ESCALADE
  • 6.2L
  • V8
  • 2WD
  • AUTOMATIC
  • 175,000 MILES
Hello there, I had a collapse lifter on cylinder #4. I took the challenge to do it on my own and everything went smoothly. I made sure there was no damage to the camshaft I could see it and it looked perfectly fine. After putting the car back together and made sure everything was fine car fired right up took it for a drive and about 15 minutes and I could feel the engine starting to lose power, check engine line came on, stable link came on, service traction control warning was displaying on the screen.

hooked up my x431 Pros mini to see what the codes were, and it showed misfire on cylinder #4.

After replacing the lifter I could still hear a little knocking, ticking coming for the same side of the engine, it was nothing compared to before that had an awful sound like it was grinding metal.

thinking I might have messed up somewhere I did a compression test on cylinder #4 and it shows 150 PSI.

i hook up the scanner to see live data and this is what it shows, not making lots of sense to me. Funny thing is that on the live data while idle shows misfire starts at 1 all the way to 199 and resets.
if I press the accelerator pedal to 2,000 RPMs the misfire doesn't happen any more on cylinder 4 and the engine feels smooth.
i even swapped the spark plugs and ignition coil from the cylinder right next to that one to rule out any possibility that it was the ignition coil.
also check injectors they are all reading 14 ohms.
here are some pictures maybe someone out there knows what he is looking at.
Sunday, February 5th, 2023 AT 6:29 PM

7 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,458 POSTS
The fact that there is still a noise on cylinder #4 is bothersome. When you removed the lifter did you check the camshaft lobe? and you upload an image of the bad lifter where it contacts the camshaft? The pattern looks like the injector is bad, even though you have a good ohms reading the nozzle could be partially clogged.

Here is how you can test the injector by following the guide below:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Here is how to remove the injector in the images below, also if you could upload a short video of the engine noise, I can tell for sure what's going on. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem. Does the scanner show any codes?

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Monday, February 6th, 2023 AT 11:41 AM
Tiny
DARKFREELIFE
  • MEMBER
  • 36 POSTS
I did check the camshaft love looked to be i. A pretty good shape to me, I rotated the crankshaft pulley all the good take a real good look at it. The lifter did show miner signs of wear when it collapsed. I think I still have them laying around and will look for them and upload pictures. I will be changing the injector as recommended. It does have a couple of codes I will pull them again when I get back home from work.
Thank you for your reply.
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Monday, February 6th, 2023 AT 12:03 PM
Tiny
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Unfortunately, I do not have the collapse lifter to take a picture of how it looks where it used to ride on the cam lobe, I do remember a tiny wear mark on one spot nothing else. Here is the picture of the code and two videos of the noise.
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Monday, February 6th, 2023 AT 3:33 PM
Tiny
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  • 36 POSTS
You can hardly hear the noise on top, but you definitely hear it more at the bottom by where the wheel goes. I was thinking if the lobe on the camshaft was bad would it have failed the compression test?
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Monday, February 6th, 2023 AT 3:37 PM
Tiny
KEN L
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Thanks for the videos, they help. The compression test will be okay if the lobe is worn but not flat. It does sound like valvetrain noise for sure so I am leaning toward camshaft damage. This will cause the knock sensor to be activated and produce the p0300 code. Sorry, I would pull the valve cover and the fuel pump fuse, then crank the engine over and compare the lift of the rocker arms to the other rocker arms in that bank. Please show a video of the lift so I can see.
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Tuesday, February 7th, 2023 AT 12:09 PM
Tiny
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  • MEMBER
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Thank you for your reply, sir. I will not risk it anymore I already ordered the OEM camshaft and the rest of the parts to do it. I'm not sure what other parts I will need since this time I'm taking the timing chain cover plate off and the rest of the front of the engine. Any recommendations?
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Wednesday, February 8th, 2023 AT 8:03 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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I would do the front main seal; water pump and you will need a timing cover gasket set and you might as well do the timing chain. Here are the instructions on how to do the camshaft replacement job. You will need to remove the cylinder heads so you might as well do a valve job and have the heads resurfaced. Change the oil and filter once you are done with the job. Also here is a video of an LS build so you can see what you are in for when doing the job:

https://youtu.be/QOr3m815pIQ

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.
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Thursday, February 9th, 2023 AT 10:51 AM

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