Cylinder pictures

[mikelit]

I have been having performance issues with my stinger recently. 2021 Kia Stinger GT1 awd. I put in JB4 and HKS M40 plugs gapped at 0.024, I use 93 shell gas, but anyways, all I have are aFe intakes. I am getting corrections in 2 cylinders consistently, cyl 4 and 6, and I was told to increase my torque on all the plugs to 25ft/lbs. While I was taking the plugs out to check the gap and re-torque I took some pictures of the cylinders, pistons head, and 2 of the intake values. Can someone give me an analysis on if something looks bad, and how bad it is visually?

Cylinder 1:

https://imgur.com/a/RoKsRbh

Cylinder 2:

https://imgur.com/a/Ja167Tk

Cylinder 4:

https://imgur.com/a/U38XYWs

Cylinder 5:

https://imgur.com/a/OsU5HdN

Cylinder 6:

https://imgur.com/a/9pay9jE

 

[oddball]

Those look perfect. There will always be buildup on intake valves, and direct injection will always have more.
Only having corrections on 2 cylinders - and consistently on two - is a little unusual but there's a lot of different things that could be contributing. Make certain the spark plug boots are in good shape. If it's the first style with a hard plastic section then look extremely close at them. They can arc in the middle causing ignition problems and the signs are very subtle. The second style that are all rubber - more like typical coil boots - are less likely to arc.
Could also try moving the plugs and coils just to rule out a physical issue.

 

[mikelit]

Those look perfect. There will always be buildup on intake valves, and direct injection will always have more.
Only having corrections on 2 cylinders - and consistently on two - is a little unusual but there's a lot of different things that could be contributing. Make certain the spark plug boots are in good shape. If it's the first style with a hard plastic section then look extremely close at them. They can arc in the middle causing ignition problems and the signs are very subtle. The second style that are all rubber - more like typical coil boots - are less likely to arc.
Could also try moving the plugs and coils just to rule out a physical issue.

I have the full rubber boot, I tried changing boots from cyl4 (worst corrections, cyl6 is second worst) to cyl2, but the corrections didn't move. I am going to have a more in-depth posting about my corrections after I do more testing with different fuels. I just rechecked the gaps and all are at 0.024, and I torqued them down to 25ft/lbs, and the boot bolt to 11 ft/lbs. I reset the ECU and will check what the corrections are looking like after the tables are learned. This was happening before, and I got new plugs and the corrections are still happening, which takes away the boot or plug being bad, I didn't see any significant yellow markings on any of them either. There is no video on removing the injectors, so I am not too ready to try that.

Back to the pictures, the dealer told me when I did my oil feed recall that I had cylinder scaring, does it look like I have that at all? I am not sure at all what good and bad cylinders look like. Mind you, I am at 50k miles.

 

[Thomby]

I'm not an expert on engine teardowns, but your pictures don't show either wet/oily or dry/carbon buildup on the pistons, and you can still see the cross hatching on the cylinder bore. Harder to tell on the valves, so I guess you could have some weird buildup leading to hot spots, but I'd start with the simple stuff first.

I am getting corrections in 2 cylinders consistently, cyl 4 and 6, and I was told to increase my torque on all the plugs to 25ft/lbs

Cylinders 4 & 6 are the back two on the driver's side, so they may just get the least airflow and knock first. If you've already checked spark plug gap, and the coil pack connections (plug side & harness side), have you tried a different gas station? Pulled logs on a lower map to see if it happens at lower boost (not sure what map you're running)?

I'd be careful about arbitrarily increasing spark plug torque, given our aluminum heads. I just went wrist tight, which I assume is more like 10-15 ft-lbs (not sure I've seen a Stinger spec).

 

[mikelit]

I'm not an expert on engine teardowns, but your pictures don't show either wet/oily or dry/carbon buildup on the pistons, and you can still see the cross hatching on the cylinder bore. Harder to tell on the valves, so I guess you could have some weird buildup leading to hot spots, but I'd start with the simple stuff first.


Cylinders 4 & 6 are the back two on the driver's side, so they may just get the least airflow and knock first. If you've already checked spark plug gap, and the coil pack connections (plug side & harness side), have you tried a different gas station? Pulled logs on a lower map to see if it happens at lower boost (not sure what map you're running)?

I'd be careful about arbitrarily increasing spark plug torque, given our aluminum heads. I just went wrist tight, which I assume is more like 10-15 ft-lbs (not sure I've seen a Stinger spec).

I get corrections on Map 0, gets worse Map 1, and worse Map 2. I also get that cyl5 180 spike on every map, not just map 2, and pretty frequently, not sure what that is about.

I did not check the harness side, so I can check that, do you have more details on that (just cause I never looked at it and don't know where to start). Here is the log that I am currently trying to fight, I have also attached the CSV:


I have tried different gas stations (2 different shells 93 and a Sunoco 94, sameish result, but I will be more thorough once my knock tables relearn). I even tried E30, still got corrections (less, but still there). I will post updated logs in a separate thread, in this one I am more concerned about my cylinder health.

I took the torque spec for plugs from the sleepytuned recommended maintenance website.

 

[oddball]

There's not much apparent scoring in the limited bit of the walls in those pictures. I wouldn't worry about it unless you're burning oil or getting blowby. Some scoring is normal and not that big of a deal. I'm very surprised they took a look at the cylinders for the oil feed recall - there's no need to pull plugs as part of that process.
I would strongly recommend moving the **coils**. E.g. swap 1&3 with 4&6. If the corrections are still just on 4&6 then something else is going on. It could be wiring to the coils, but I'd start looking at air leaks or fuel distribution problems.

Moving direct injectors is extremely hard. I wouldn't bother with that unless you're in deep trouble.


Torque on the coil bolt really doesn't matter - just tight enough to stop it from moving.

 

[mikelit]

There's not much apparent scoring in the limited bit of the walls in those pictures. I wouldn't worry about it unless you're burning oil or getting blowby. Some scoring is normal and not that big of a deal. I'm very surprised they took a look at the cylinders for the oil feed recall - there's no need to pull plugs as part of that process.
I would strongly recommend moving the **coils**. E.g. swap 1&3 with 4&6. If the corrections are still just on 4&6 then something else is going on. It could be wiring to the coils, but I'd start looking at air leaks or fuel distribution problems.

Moving direct injectors is extremely hard. I wouldn't bother with that unless you're in deep trouble.


Torque on the coil bolt really doesn't matter - just tight enough to stop it from moving.

I ordered 2 new coil packs, one for cyl4 and one for cyl5 (the one with the 180 ign spikes). Will try swapping them when they come in. I also will be changing FUA to 1 to observe the actual timings per cylinder.

I have to measure out my discarded oil next oil change to see how much is getting burned. What is a normal amount for our cars? Not sure what you mean by getting blowby, I thought we always get blowby? I have the mishimoto catch can and it gets like a teaspoon or 2 (have not really measured that exactly) full between 5k mile oil changes.

When they did the recall, they pulled the engine out and when they put it back in, they destroyed a coolant line. Coolant went everywhere when they started the car up. I guess since they had it in there waiting for the new extremely back-ordered line, or really whenever, they checked my oil and saw it was low. This probably led them to investigate why, and probably looked in the cylinders and said they saw scaring (this is just my guess and I am not sure if this actually happened).

Yea you are right with the injectors, I am really not interested at all in touching those. I am gonna be putting in BG 44K in there soon to hopefully give them a good cleaning as well as CRC intake cleaner. If none of that helps, I am considering taking it to the dealer, pulling the JB4 out first obvs, and telling them that the car is sluggish (because I get high 5's map 0 0-60 time, which is probably related to my timing corrections) and see if they can find anything. Hopefully it would be covered under warranty.

 

[oddball]

Measuring the oil that drains is only useful if you do that over several oil changes. A lot of oil gets stuck in various places in the engine. You can never drain all the oil and the precise amount that drains depends on temp, how long the engine ran, how recently it ran, how long you let it drain, etc etc.
If you never notice the oil level changing on the dipstick over a ~5k interval then it's not burning oil.

Yeah, there is always some blowby. What I mean is excessive. e.g. if you disconnect the catch can while the engine is running and you get a constant strong stream of cloudy gasses then something is wrong. Especially at idle there may be a bit of gasses coming out but it shouldn't be very noticeable.

 

[mikelit]

Measuring the oil that drains is only useful if you do that over several oil changes. A lot of oil gets stuck in various places in the engine. You can never drain all the oil and the precise amount that drains depends on temp, how long the engine ran, how recently it ran, how long you let it drain, etc etc.
If you never notice the oil level changing on the dipstick over a ~5k interval then it's not burning oil.

Yeah, there is always some blowby. What I mean is excessive. e.g. if you disconnect the catch can while the engine is running and you get a constant strong stream of cloudy gasses then something is wrong. Especially at idle there may be a bit of gasses coming out but it shouldn't be very noticeable.

I don't think I would be getting a strong stream judging by the amount the can has during oil changes.

Do you have any other recommendations before I take it to the dealer? If I end up going, what do you think I should tell them?

Don't get me wrong, it still is quick, but it just doesn't seem as quick as it should be, especially after adding the JB4 (telling by the 0-60 times). Should I just say sluggish performance? Basically how to not tell them that I am using a JB4.

 

[5tinger]

How many miles on it?

 

[mikelit]

How many miles on it?

50k