Is this normal? "forced misfire" 2018 Civic Si (Ktuner)

Can you replicate this?

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mpir413

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Recently I've noticed that I can force a misfire or induce the K.count to increase. I'm wondering if this is normal, and others can replicate the issue, or if I have a potential problem on my hands. I do this by holding the throttle up to 2500 and slowly letting off. While driving I noticed that my stft were jumping as high as 30% while under the similar conditions. I also have a data log of this event if anyone is interested. I can do this on a stock calibration as well.
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JT Si

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I noticed something strange in the same vein yesterday after I parked coming home from work.

If I hold revs around 1250-1300, then lightly blip the throttle to raise them to 1900, then let off the throttle enough to drop the revs back down to 1250-1300 there is a thunk you can hear and feel as it drops, around 1400-1450 RPM.

I noticed that the ignition timing goes from positive (20ish) to negative (-10) exactly when the thunk happens.

This is stock calibration, no tune of any kind. If I rev higher than 1900 or more quickly up and down it does not occur.

Strange quirks I would think.
 
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mpir413

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I noticed something strange in the same vein yesterday after I parked coming home from work.

If I hold revs around 1250-1300, then lightly blip the throttle to raise them to 1900, then let off the throttle enough to drop the revs back down to 1250-1300 there is a thunk you can hear and feel as it drops, around 1400-1450 RPM.

I noticed that the ignition timing goes from positive (20ish) to negative (-10) exactly when the thunk happens.

This is stock calibration, no tune of any kind. If I rev higher than 1900 or more quickly up and down it does not occur.

Strange quirks I would think.
Yes Strange indeed. especially for a car with such low miles like mine.I really like to know what is going on here. Although I am great full that you replied, I was hoping to get many more responses to try and get to the bottom of this.
I'm definitely aware of the "Thunk,thud, or slight pop you mentioned that is quite noticeable when the event happens. I would like to know if it is a back fire or worse knocking.
Would you be down to see if you can replicate the same issue with your car, and see if it is also triggering the k count, when this happens and let me know what you find? How many miles on your car?

i feel that my car has been acting funny for quite some time now. weird erratic fuel trims and loss of HP/TQ. At idle and lightly cruising around my combined fuel trims can go as high as 18%, but when pushing the car they return to 0. very odd i feel it may be something like a vacuum leak,or something in the fuel system like clogged injectors. IDK.
I also feel that there is a loss in power. When i first got ktuner, if I pegged the throttle less than 4k rpms in any gear 4th+ it would make my clutch slip. by rolling into it, it would make the car off like a rocket. "when I could get the clutch to catch." Also wot in 2nd gear would rip, suck you back in the seat hard and if i didn't feather the throttle the tires would break loose. these things don't happen anymore. wot in 2nd doesn't break tires loose, they barely screech. and wot in 4th gear no longer slips the clutch. when I did these things, i never dumped the clutch or shifted hard, id be in gear fully and mash or roll into the petal.

I have no check engine light so it makes me crazy. and before someone says its the warmer weather, these things have been happening since before it started to , warm up. I even have much cooler mornings here in Boston, MA when I leave @ 4:30am to go to work. and nothing changes.
 


JT Si

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Yes Strange indeed. especially for a car with such low miles like mine.I really like to know what is going on here. Although I am great full that you replied, I was hoping to get many more responses to try and get to the bottom of this.
I'm definitely aware of the "Thunk,thud, or slight pop you mentioned that is quite noticeable when the event happens. I would like to know if it is a back fire or worse knocking.
Would you be down to see if you can replicate the same issue with your car, and see if it is also triggering the k count, when this happens and let me know what you find? How many miles on your car?

i feel that my car has been acting funny for quite some time now. weird erratic fuel trims and loss of HP/TQ. At idle and lightly cruising around my combined fuel trims can go as high as 18%, but when pushing the car they return to 0. very odd i feel it may be something like a vacuum leak,or something in the fuel system like clogged injectors. IDK.
I also feel that there is a loss in power. When i first got ktuner, if I pegged the throttle less than 4k rpms in any gear 4th+ it would make my clutch slip. by rolling into it, it would make the car off like a rocket. "when I could get the clutch to catch." Also wot in 2nd gear would rip, suck you back in the seat hard and if i didn't feather the throttle the tires would break loose. these things don't happen anymore. wot in 2nd doesn't break tires loose, they barely screech. and wot in 4th gear no longer slips the clutch. when I did these things, i never dumped the clutch or shifted hard, id be in gear fully and mash or roll into the petal.

I have no check engine light so it makes me crazy. and before someone says its the warmer weather, these things have been happening since before it started to , warm up. I even have much cooler mornings here in Boston, MA when I leave @ 4:30am to go to work. and nothing changes.
I do not have a ktuner or other method to measure knock control, just a scangauge II and I am unaware of an xcode for it to read that out.

I'm at 6,500 miles, never tuned but I have a 27Won intake.

I misremembered as I was able to repeatedly reproduce it again yesterday - 1100 RPM to 1500 RPM slowly and drop back to 1100 clunks at 1250-1300.

I'll try to do it again today and look at the fuel trims.
 

Mcclaughry95

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I tuned but for me to get kcontrol down I have to do some hard pulls. Cruising doesnt help any for me. I'm going to try that when I leave work tonight and see if i get it.
 

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I'd recommend reaching out to KTuner directly, either by email or in their sponsor thread, and send them your datalog.
 

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Recently I've noticed that I can force a misfire or induce the K.count to increase. I'm wondering if this is normal, and others can replicate the issue, or if I have a potential problem on my hands. I do this by holding the throttle up to 2500 and slowly letting off. While driving I noticed that my stft were jumping as high as 30% while under the similar conditions. I also have a data log of this event if anyone is interested. I can do this on a stock calibration as well.
any updates ? vid is gone.
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