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2013 Kia Optima SXL
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Discussion Starter · #1 ·
I’ve been having cyl 2 misfires ever since I installed it all I have is injen short fam intake and HKs plugs.
can anyone help w the situation?also what should my next performance mod be? I’m having trouble choosing I was thing dp or mid pipe or chargepipe
 

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2013 Ebony SXL Turbo: Original Everything @ about 189K with Drag wheels.
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From jb webpage:

"It's well documented the Kia and Hyundai platforms are prone to spark blow out at both stock and higher than stock boost levels. At a minimum, the factory spark plug gap should be closed to 0.026". Alternatively, replacement spark plugs can be used that offer a stronger spark and are more reliable than stock. "

Did you adjust for the above?
 

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2018 KIA Optima
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171 Posts
Replied in other thread. Reposting here so it isn't missed

Hks makes many different models. It's like saying I have a kia vs I have a kia optima SXL. You have HKS spark plugs XXXXXXX etc. Exactly what plugs do you have. How much was the set, or where did you buy them. (Will help figure out if you have the right ones or not)

With the advanced timing boost and tune in play they require a specific plug. If you have the wrong one. You will get misfires, poor preformance and possible detonation of your engine.

People have also noted using tune on wrong octane setting giving them issues. But I'm not sure about that one.
 

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2013 Kia Optima SXL
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Discussion Starter · #5 ·
From jb webpage:

"It's well documented the Kia and Hyundai platforms are prone to spark blow out at both stock and higher than stock boost levels. At a minimum, the factory spark plug gap should be closed to 0.026". Alternatively, replacement spark plugs can be used that offer a stronger spark and are more reliable than stock. "

Did you adjust for the above?
I have the HKS M45XL spark plugs from K5OS I don’t see why I’d be having misfires? Those are recommended aren’t they? And to my knowledge I looked and the cyl 2 plug looks fine imo
 

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2018 KIA Optima
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I have the HKS M45XL spark plugs from K5OS I don’t see why I’d be having misfires? Those are recommended aren’t they? And to my knowledge I looked and the cyl 2 plug looks fine imo
Those are the recommended plugs. Did you check the Gap when installed? They are set from the factory, but things happen.

Are you using the correct map to octane? And been using that octane for 2 full tanks. If someone put 87 in it, it takes 2 full tanks to dilute out to a different octane. Also. Gas isn't all made the same. Some additives can cause issues. So using the diffeent brands can be problematic. Same 2 tanks to clear though.

Have you had the updates from the manufacturer? I'm not sure if an older misfire code could be the engine knocking code post update. I have not had experience with that one.
 

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Discussion Starter · #8 ·
Those are the recommended plugs. Did you check the Gap when installed? They are set from the factory, but things happen.

Are you using the correct map to octane? And been using that octane for 2 full tanks. If someone put 87 in it, it takes 2 full tanks to dilute out to a different octane. Also. Gas isn't all made the same. Some additives can cause issues. So using the diffeent brands can be problematic. Same 2 tanks to clear though.

Have you had the updates from the manufacturer? I'm not sure if an older misfire code could be the engine knocking code post update. I have not had experience with that one.
I run 93 octane in map 1 sometimes from shell V Power and I got told you can’t regap those spark plugs but I have changed out the ignition coil and same issue and the spark plug looks fine so maybe it’s a gap issue? Idk I really need some insight
 

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It's been awhile, so I might be wrong.
Map 1 isn't 93 octane map.

Check with BMS. They might ask for a log and be able to help more.
 

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Didn't you contact them already?

I have the jb4 hooked up as of now they fixed the issue and had to send me a new board for it b I’m looking for a custom tune specific for best performance with the tune and my aftermarket parts I recently added
 

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I’ve been having cyl 2 misfires ever since I installed it all I have is injen short fam intake and HKs plugs.
can anyone help w the situation?also what should my next performance mod be? I’m having trouble choosing I was thing dp or mid pipe or chargepipe

Pretty much anytime you have a misfire especially after a plug change totally check the plugs. The gap could be bad, heck even the plug itself... It may fire but it may be damaged also. Meaning it'll never fire right. I've even had really nice plugs completely fail within a few days also. Had one where the ceramic split and it was so tiny I kept blowing it off because I couldnt see it but the car was bucking and pissed off at me so I knew it was still related. It's hilarious though I've seen plugs fouled so bad from never changing them where there's literally a ball of junk hanging from the end and you're scratching your head how did this even run? Then a tiny gap misadjustment can completely ruin your experience.
 

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I’ve been having cyl 2 misfires ever since I installed it all I have is injen short fam intake and HKs plugs.
can anyone help w the situation?also what should my next performance mod be? I’m having trouble choosing I was thing dp or mid pipe or chargepipe
Ive had trouble with #2 detonating sometimes even on 93 with the hks plugs. Pull the plug and hold it up with the electrode facing down. I guarantee the ceramic around the electrode cracked and is bouncing around. You won't see it looking at it with the plug turned upside down because the ceramic slides back into place. Killed 2 sets and failed the exact same way each time. Happens when you don’t give it time to warm up and hammer on it right away. Btw I joined here just to answer this lol
 

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2012 Black SX Prem. & Tech.
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Ive had trouble with #2 detonating sometimes even on 93 with the hks plugs. Pull the plug and hold it up with the electrode facing down. I guarantee the ceramic around the electrode cracked and is bouncing around. You won't see it looking at it with the plug turned upside down because the ceramic slides back into place. Killed 2 sets and failed the exact same way each time. Happens when you don’t give it time to warm up and hammer on it right away. Btw I joined here just to answer this lol
Thanks for the contribution!

I had a similar issue, where the ceramic would slide down if you held the plug as you describe. But that was back in the old days, when I still had the OEM plugs. So far the replacement OEM plugs (Hyundai 18849-09085 (NGK SILZKR8E9G) superseded the originals) are working fine. Engine runs nice and smooth.

But I'm running stock engine, no tune or any mods. I've swapped back and forth between the OEM plugs above and the Aftermarket plugs NGK (1422) ILKR8E6. However, I ran into rougher idle and even had an error code using these 1422 plugs. I tried two different gaps, at 0.028, and 0.025, and still after about a month the engine would noticeably vibrate more, I could feel it more through my feet. Swapping back to OEM the engine ran smooth as silk.
 
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