Can spark plugs cause misfire only under load?

[DoctorStiches]

most likely a coil rather than the plug

It was the plug

 

[MerlintheMad]

^^^Not just the plug: in the interim I have experienced the "chugging" again. Today the CEL came on twice, first in Eco, and it stayed on for c. ten seconds; the second time in Sport and it went out quickly after I stopped WOT. I have a diagnostic appointment with Jerry Seiner, South Jordan, on the 28th Instant. Will keep you informed as to the result of that when it happens.

Also, I told them to look into the washer fluid not coming out when the outside temperature showed as low as 19F: told them that as I checked the refill spout, where it closes to the narrow hole the fluid looked somewhat coagulated, making me suspect that it froze. That should never happen, of course, so, we'll hopefully get to the bottom of that at the same time as diagnosing the "chugging" issue returning. (Without knowing anymore about this than what I read, I suspect a compromised coil pack, probably the one that went with the cracked spark plug that I drove hundreds, possibly thousands, of miles on.)

 

[GetStung915]

^^^Not just the plug: in the interim I have experienced the "chugging" again. Today the CEL came on twice, first in Eco, and it stayed on for c. ten seconds; the second time in Sport and it went out quickly after I stopped WOT. I have a diagnostic appointment with Jerry Seiner, South Jordan, on the 28th Instant. Will keep you informed as to the result of that when it happens.

Also, I told them to look into the washer fluid not coming out when the outside temperature showed as low as 19F: told them that as I checked the refill spout, where it closes to the narrow hole the fluid looked somewhat coagulated, making me suspect that it froze. That should never happen, of course, so, we'll hopefully get to the bottom of that at the same time as diagnosing the "chugging" issue returning. (Without knowing anymore about this than what I read, I suspect a compromised coil pack, probably the one that went with the cracked spark plug that I drove hundreds, possibly thousands, of miles on.)

I'm having the same issues. Going to replace coils and plugs. Hopefully it fixes my problems.

 

[MerlintheMad]

I don't know what to think. This afternoon I got in a good WOT dig in Sport mode. TSC were OFF, because I had earlier set up for Launch Control (but got shut down by turning cars in the last few seconds before the light turned green). I felt only smooth power. So, to what extent is the TSC inhibiting smooth boost by responding to "signals" from the road surface? Or is this issue just intermittent because of a complex of variables? (Heh, maybe they'll find another cracked plug: my diagnostic appointment is two weeks from today.)

 

[DoctorStiches]

I don't know what to think. This afternoon I got in a good WOT dig in Sport mode. TSC were OFF, because I had earlier set up for Launch Control (but got shut down by turning cars in the last few seconds before the light turned green). I felt only smooth power. So, to what extent is the TSC inhibiting smooth boost by responding to "signals" from the road surface? Or is this issue just intermittent because of a complex of variables? (Heh, maybe they'll find another cracked plug: my diagnostic appointment is two weeks from today.)

The traction control will kill all the power if you hit even a little bit of gravel and get some tire slip I never experienced that myself but I don't know what the road is near you or rather I only experience that when I'm making a 90ﾟ turn and also flooring its the only time if it happens in a straight line and very often I don't believe that would be the case

But yea. If i sat with you and watched and felt what happened i could help more

 

[MerlintheMad]

The traction control will kill all the power if you hit even a little bit of gravel and get some tire slip I never experienced that myself but I don't know what the road is near you or rather I only experience that when I'm making a 90ﾟ turn and also flooring its the only time if it happens in a straight line and very often I don't believe that would be the case

But yea. If i sat with you and watched and felt what happened i could help more

All power? Well, TSC isn't a factor then.

Yesterday I proved that something engine related is positively behind this. I did a launch control from pole position northbound at 9800 South, WOT to above 70 MPH: the CEL came on (and stayed on for a solid minute or more), and while I didn't feel hesitation or "chugging", something felt a little bit rough. I'm guessing that when I take it in for the diagnostic that they'll find another cracked plug or a compromised coil pack or both. Hopefully, it will be that easy to find the problem.

 

[DoctorStiches]

Ok my big brain moment.
Injectors could become clogged and are not causing problems untill your pushing as much fuel as possible....
It would not hurt (but i know your all stock) to plug in a diagnostic pda and see the active fuel air ratio. If the car is leaning out as in not getting enough fuel it may cause this... but bottom line im not a pro and your car is having trouble. I wish luck and more^_^

 

[cncBilly]

All power? Well, TSC isn't a factor then.

Yesterday I proved that something engine related is positively behind this. I did a launch control from pole position northbound at 9800 South, WOT to above 70 MPH: the CEL came on (and stayed on for a solid minute or more), and while I didn't feel hesitation or "chugging", something felt a little bit rough. I'm guessing that when I take it in for the diagnostic that they'll find another cracked plug or a compromised coil pack or both. Hopefully, it will be that easy to find the problem.

Perhaps it’s time for you to invest in a JB4. Not for the extra power as we all know you are happy with stock but for the logging capabilities. This would also open you up to a whole new level of understanding how your car is working. Might be fun, ya know an old dog learning new tricks. Just a thought my friend.

 

[MerlintheMad]

^^^I'll ask the service guys what they think. Thanks for the ideas. I will have this thread pulled up on my laptop when I go in, and let them take a look: plus they are going to do a diagnostic, so, wouldn't that point to dirty injectors?

Injectors could become clogged

 

[MerlintheMad]

Today things got worse: I accelerated onto the Bungler Hwy and the CEL came on and stayed on until I coasted down and put it in Eco. At 9800 South I got pole position and did a launch: power definitely down and engine running a bit rough: CEL did not go out the rest of the way home (c. 5 to 10 minutes), except when I coasted (no throttle input). In the driveway I put it in "P" and tried to red line it and could only raise c. 5K RPM max. *sigh* A whole week to go until my diagnostic.

 

[D.J.]

Today things got worse: I accelerated onto the Bungler Hwy and the CEL came on and stayed on until I coasted down and put it in Eco. At 9800 South I got pole position and did a launch: power definitely down and engine running a bit rough: CEL did not go out the rest of the way home (c. 5 to 10 minutes), except when I coasted (no throttle input). In the driveway I put it in "P" and tried to red line it and could only raise c. 5K RPM max. *sigh* A whole week to go until my diagnostic.

I believe that 5k rpms in park is the normal.... Not a fault.

Pretty sure actually.

Different fuel cut rev limit in park vs drive. (I'm 90% sure).

 

[MerlintheMad]

I believe that 5k rpms in park is the normal.... Not a fault.

Pretty sure actually.

Different fuel cut rev limit in park vs drive. (I'm 90% sure).

How do we find out? I hadn't ever revved it stationary before and just assumed I could rev it to the red line.

 

[D.J.]

How do we find out? I hadn't ever revved it stationary before and just assumed I could rev it to the red line.

I would look pretty silly to my neighbours of I went out to my driveway and just started revving my car to infinity and beyond in my driveway right now....

But tomorrow - I'll be driving, obviously an easy test.

 

[D.J.]

How do we find out? I hadn't ever revved it stationary before and just assumed I could rev it to the red line.

Cost me only $20 at the pump for this 6 seconds.

Lol

It's the same in both neutral and park.

https://imgur.com/a/8iiELbJ

 

[JSolo]

I was always taught that free revving (no load) an engine is bad. Something about excessive vibrations potentially causing damage¿?

 

[D.J.]

I was always taught that free revving (no load) an engine is bad. Something about excessive vibrations potentially causing damage¿?

I don't worry about such things.


This is likely an old wives tale based on old 2 stroke engines where there is "some" truth. 2 stroke - prolonged high RPM with no load means less fuel and hence less oil for lubrication, since the oil is in the fuel, and even then - prolonged isn't a few seconds.


Never heard anything about excessive vibrations, also, my engine didn't excessively vibrate

 

[JSolo]

Never heard anything about excessive vibrations, also, my engine didn't excessively vibrate

Yet

 

[MerlintheMad]

Never heard anything about excessive vibrations, also, my engine didn't excessively vibrate

Mine does at the moment. Where there was zero vibration before, now there is a noticeable added vibration that says to me that one cylinder is missing.

I was always taught that free revving (no load) an engine is bad. Something about excessive vibrations potentially causing damage¿?

Did you ever watch this video?

Add to that the fact that Kia engineers safety limits well below the "torture test", and we cannot hurt our engines. It is basically impossible to over-rev them. But until yesterday, I thought that we could at least bounce off the red line. Nope. When we drive in automatic the trans upshifts well below the red line. When we use the paddle shifters, the trans logic in the ECU takes over control of the shift points if we don't upshift soon enough.

Until yesterday, I had never sat and revved my engine even moderately: I saw no point in it: but yesterday I felt like feeling and hearing how it is with the CEL ON: and wishful thinking made me wonder if I could somehow "blow it out", i.e., clear whatever was fouling my plug(s): I was, and am, in distress over this (didn't sleep very well last night either, heh): so, I revved it and then determined (erroneously) that my missing cylinder was causing the available revs to be c. a thousand below normal. Glad that isn't true!

Now, I am wondering if I can/should drive on this. I won't do any "spirited" driving in the next six days, but can I drive like a normal grandpa person without risking any damage? What do you guys (especially you car guys) say to that?

 

[JSolo]

You realize, now all the kids will go out there and rev their engines.

Wonder if kia's built in proper logic to handle a neutral drop.....?

Merlin, what code(s) were set? Given the level of sophistication in today's vehicle's, I'd think if it was a serious issue, ecu would be in limp mode.

 

[MerlintheMad]

My Launch control was down on power, but still far above what I have seen described as "limp mode". No codes (I've been watching for any), only the CEL.

If I am not seeing any codes and the car otherwise runs fine (other than the gimpy feeling from a misfiring cylinder), am I okay to drive sedately on it?

Merlin, what code(s) were set? Given the level of sophistication in today's vehicle's, I'd think if it was a serious issue, ecu would be in limp mode.