Misfire on cylinder three?

BHAMDOC1973

MEMBER
2017 HYUNDAI SANTA FE
4 CYL
TURBO
2WD
AUTOMATIC
122,000 MILES

Super clean car with a 2.0T engine. Bought it cheap as it misfires on cylinder 3. Swapped coil and spark plug, same results. Only code is misfire on cylinder 3. Checked compression and its zero, cylinder 2 had 120 PSI. Ugh, do these usually have issues with pistons or valves? Recommend removing valve cover to see? I took some pictures using the camera, maybe you can see something. The plug had a lot of fuel on it.

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5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,513 POSTS

No compression is the problem. I would remove the valve cover to see if the valve is being held down or is stuck in the head. I have seen valve seats come loose from the cylinder head and cause this problem which will be accompanied by a low valve stem height. Here is how to remove the valve cover so we can start to fix it.

This guide can help as well:

https://www.2carpros.com/articles/the-reasons-for-low-compression

With the camshaft lobe away from the valve see if there is play in the valve follower. Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.

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Tuesday, November 21st, 2023 AT 6:12 PM

BHAMDOC1973

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1,553 POSTS

What do you mean by this? With the camshaft lobe away from the valve see if there is play in the valve follower.

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Tuesday, November 21st, 2023 AT 6:15 PM

KEN L

MASTER CERTIFIED MECHANIC
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So, when the valve is not being pressed down by the camshaft see if there is play in the roller follower, if there is the valve seat has fallen out or the valve is damaged.

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Thursday, November 23rd, 2023 AT 9:25 AM

BHAMDOC1973