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post #1 of 37 Old 02-27-2018, 09:19 AM Thread Starter
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Engine Stumbling - misfiring

Short story, had the car, a 2016 forte5 SX for a year and a half. Runs great, decent fuel mileage. Got in a mostly cosmetic collision in october. Took it to the collision center. a week later i'm told the washer fluid reservoir is on back order for a month, and the can't release the car without it. Annoying, but it happens. they provided a loaner vehicle for the duration at least. A month later i'm told the part should be in the next day or so. 3 days later i get the call that the part is on back order another month... wonder if they ordered the wrong part? Any way, Dec 22 i get the car back.

Headlights are pointing all over the place, but the bodywork is good. A few days later i start it in the cold, and go back inside to let it warm up, and i hear it banging and stumbling, the roar up to 2200 rpm, an settle down to a stumbly idle. Car has ~36K Km's on it

next cold start i record it, same deal. start it, runs normalish for almost exactly a minute, CEL comes on, rpms drop below 200, engine bangs and shakes the whole car a couple times, screams up to 2200 rpm and levels off again. OBD shows misfires on all the cylinders.

Take it to the dealer with the CEL still on, they disappear into the back for a few hours, come back and tell me nothing is wrong, maybe some water in the fuel lines. Ran some water remover in the next tank, seemed better. unit a month later it does it again. Fuel consumption is ridiculous at this point. 1/2 tank, 20 ish liters to drive 180 km of 90% highway driving. thats over 11L/100km. Last winter it was in the high 7's low 8's on the highway.

Go back to dealer, but the CEL had turned itself off at this point, they tell me "light not on, can't do anything" they literally do nothing, not even pop the hood and send me off.

Any idea what's going on, or why the dealer won't do anything?

https://youtu.be/7Gd6yiHWscc Magic happens around the 1 minute mark.
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post #2 of 37 Old 02-27-2018, 11:08 AM
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One minute is just about how long it takes for the engine to go CL, so it's probably some issue related to one of the sensors that participates in CL, or perhaps a vacuum line. And there's also a good chance it's related to the work the body shop did. So take a look at all of the ground connections, wiring, sensor connectors, and vacuum tubing anywhere near the area of the body damage. It also might be helpful to gently push on everything in the engine bay that moves, during the time the engine is stumbling. A realtime OBD data stream scanner might be a big help in pinpointing the problem, if you can't find it with a visual inspection.

It comes as no surprise to me that the stealership wasn't able to do anything. Take it to a good independent shop if you're unable to find the answer yourself.

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post #3 of 37 Old 02-27-2018, 11:18 AM Thread Starter
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I'm unfamiliar with CL, what's it stand for?

Damage pic attached for reference, mostly cosmetic with the bumper and headlights.
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post #4 of 37 Old 02-27-2018, 01:51 PM
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CL is an abbreviation for Closed Loop. And the pics won't help anyone else with this because you need to be hands-on the vehicle, looking for whatever is wrong from the list of things I mentioned previously. And the actual problem is more likely something the body shop didn't do correctly, rather than from the damage itself. Things such as failure to reconnect ground wires tight is what you're looking for. If you can't identify the problem yourself, then take it to an independent shop.
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post #5 of 37 Old 02-27-2018, 04:36 PM
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The errors point towards the engine management. I agree with kiaguy007, start with ground wires missing, or no longer grounded, because of the spray paint, that will be a promising start. After that, I'd move on to look for any plugs, which have been left unplugged, especially air mass meter and lambda probe. (I do not know, where your damage was. Also, check fuses and relays related to engine management. Normally, they'd disconnect the battery, but what if they did not?

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post #6 of 37 Old 02-28-2018, 01:57 PM
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I wish I could get a hold of your broken headlight and fog light... I am getting ready for retrofit and need some broken headlights.


Regarding your issue.

Sure, check for ground, but honestly I do not that is the issue here. But then again - check wires going to the engine and around. From your damage it does not seem they should mess up with anything there at all.
However... read below.

A few questions first.
Once it goes back to normal, how does it behave then?
Does it have power as it used to?

You started int cold. How cold was it? About -5C? I did not hear the BOV venting, but could be hindered by other noises.

Since it is MT, when you are driving and say in 3rd gear, at 35 km/h, floor it - does it pool nicely? Engine of course at operating temp.
It should pull quite hard and have power till no less but 5500 rpm. Then stock tune tapers off a bit.

What I am leaning towards is spark plugs - that is one thing.
The other would be intercooler piping. They shoould not need to touch anything, but who knows.

They removed bumper for sure. I wonder if they put everything back as it supposed to be. You would feel power problems right away, I guess, but since your are saying it gives good fuel economy, I feel like you do not push it too much.


Last thing - coils. Some complained about them failing. I also experience rough idle, but nowhere near yours, at cold. Until the engine is fully warmed up, it acts funny. Although I am running a tune with 93 octane. Still, stock was funny.

I would remove all 4 spark plugs and check them.
As for your dealer - yeah, some of them are not so good. I am very sorry to hear yours is the bad one. I had those too in my life.


You might want to visit http://www.forteturbo.org as they have more experience with SX version.
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post #7 of 37 Old 02-28-2018, 03:25 PM Thread Starter
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Updating as I go.

Had a good look under the hood today, pulled on every connection i could reach.

image 1, engine oil coming down the intake, just above the air filter. seems to originate from a short hose leading to the top of the engine. PCV valve?

images 2 + 3, a small hose with "fuel vapour" printed on it seems like it should be more connected than it is (it's got pink paint on it for some reason) it appears to be a smaller hose wrapped in a larger one. the larger one is in 2 segments, with a gap exposing the smaller one inside. it looks like that crimp is supposed to hold them together. I pulled on it a bit, but the hoses didn't want to easily come back together, so i left it.

@PLP
Quote:
Once it goes back to normal, how does it behave then?
it seems normal after a few minutes of idling. once at operating temp it idles around 850

Quote:
Does it have power as it used to?
Seems unchanged, but the roads are still slippy, it breaks traction long before i can floor it.

Quote:
You started int cold. How cold was it?
-17C in the video

Quote:
You would feel power problems right away, I guess, but since your are saying it gives good fuel economy, I feel like you do not push it too much.
It gives horrific fuel economy, 11L/100km on the highway. prior to this it would be around 8 in the winter for highway driving.

I've got an appointment on monday with the only other KIA dealer locally, maybe they'll be more helpful. If i get the same brush off i'll find an independent shop.
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post #8 of 37 Old 02-28-2018, 03:52 PM
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Originally Posted by ragnabrok View Post
image 1, engine oil coming down the intake, just above the air filter. seems to originate from a short hose leading to the top of the engine. PCV valve?
Normal, although I hate it, because oil vapours then are being dragged down into the intake, then onto the turbine plates, where it gets heated, then onto the hot pipe and to the intercooler. Not much can be done except oil catch can. Or leave it, let KIA deal with some issues at some point (warranty claim).

Quote:
Originally Posted by ragnabrok View Post
images 2 + 3, a small hose with "fuel vapour" printed on it seems like it should be more connected than it is (it's got pink paint on it for some reason) it appears to be a smaller hose wrapped in a larger one. the larger one is in 2 segments, with a gap exposing the smaller one inside. it looks like that crimp is supposed to hold them together. I pulled on it a bit, but the hoses didn't want to easily come back together, so i left it.

I am not sure, but appears to be normal. I need to check mine.
The markings are from factory. They mark all clamps to see if anything moved or slid off.

Quote:
Originally Posted by ragnabrok View Post
-17C in the video
That explains the low idle. I noticed that mine does same thing - on very cold, like -17 C, it would quickly drop. When it is warmer (-5 to +5), it takes more time to stabilise and you hear the turbo spool, blow off vent a lot.

Quote:
Originally Posted by ragnabrok View Post
It gives horrific fuel economy, 11L/100km on the highway. prior to this it would be around 8 in the winter for highway driving.
They are known for very bad fuel economy in cold.
Stock tune runs very rich. Also, your idling (warm up) is definitely not helping...



My experience:
I never let it idle this long on cold. Maybe once, or twice, but hard to say what temp it was.
I would always, when at -20 C or so, start it, let it idle for 10-15 seconds and take off. Basically, allow the idle to stabilise, or for BOV to close. I don't let it warm up...
However, it would have some stumble about 30 seconds from the moment I took off. It was almost always in the same spot on the street. It felt like it was misfiring, or not sure how much fuel to give.

Sure, it looks like switching from Open Loop to Closed Loop (as mentioned before - oxygen sensor driving the Air Fuel Ratio, on open loop ECU has preset values).
And while now (currently I have AT, I sold the MT...) I cannot feel it this much as AT hinders many problems, I can still feel a bit of hesitation. Then it is gone.


I would suggest you to leave the car overnight, get a loaner from them, and come back the next day morning. Start the car with them and let them witness the issue.
You MUST be there, otherwise they will not do it, or will say - they could not duplicate the issue.
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post #9 of 37 Old 02-28-2018, 05:54 PM
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I can't get rid of the feeling that something is causing closed loop processing to go haywire, resulting in a rich running condition. Then the upstream O2 sensor does it's thing, levels it out to just somewhat rich, making it seem like it's running ok. However, the increased fuel usage is the smoking gun that provides evidence that it continues to run abnormally rich.

With the physical inspection not helping, I'd be using an OBD realtime data steam reader to try for additional information, but it sounds like you're not up for that type of DIY. Well, perhaps the second stealership can do better than the first one did, but typically if GDS doesn't hand them the answer, they just throw in the towel and give up. But who knows, maybe they'll prove me wrong about that, and for your sake I hope that's the way this one goes.

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post #10 of 37 Old 02-28-2018, 06:39 PM Thread Starter
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Not that i'm unwilling for some DIY, especially if i actually get results instead of being shown the door, i'm more lacking in tools and familiarity. I have a cheapo OBD2 bluetooth reader, but most of what it can read doesn't help me much. it gets a voltage reading from an O2 sensor, but i have no idea what that voltage indicates, or what it should or shouldn't be. Also, without a schematic of the engine, i couldn't find that sensor if I tried looking for it.
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post #11 of 37 Old 02-28-2018, 08:39 PM
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....I have a cheapo OBD2 bluetooth reader, but most of what it can read doesn't help me much. it gets a voltage reading from an O2 sensor, .....
So this reader doesn't display fuel trims? Voltage can be useful when trying to figure out O2 sensor errors, but isn't helpful when you're interested in watching fuel trims. Also I believe that seeing the temp and MAP sensor values might be very helpful for your problem, so the tool should do that as well. All of those things are basic functionality, so I'm wondering if perhaps what you have has some options that you're not aware of?

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post #12 of 37 Old 03-01-2018, 10:00 AM
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So get your cheap Bluetooth OBDII and get Android app Torque (Lite free or Pro for 5 USD) and see the fuel trims. Stock is set around 9-11. It DOES run rich...


EDIT.

Not sure what your trip is, but keep in mind that when you start the engine at -17 C it will be drinking initially about 4 l/h, then it drops to about 2 l/h, to finally reach level of about 1.3 l/h (liter per hour) when at operating temperature. Idle speed should be about 700-750 rpm or slightly below.
So if your trip is say 17 km, if you had 8 l/100 km previously that means you would use 1.36 l, with current 11 l/100 km, you use 1.87. The difference is about 15 minutes of cold idle...

Another thing to look could be leaking thermostat. It should hold no less than 80-82 C when driving.

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post #13 of 37 Old 03-01-2018, 10:21 PM Thread Starter
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Casual observation, I drove to a store, about a 20 minute trip. When i got there i pulled 2nd gear, floored it on cold wet road and it accelerated, but not aggressively. Left the store about half hour later, floored it in 2nd on the same road i did coming in and it almost instantly wheel hopped. it's such a huge difference in power for no apparent reason.

Attached is a snap from the ODB reader in torque. from the top left lists, Air/fuel mix, RPM, 02 bank 1, another 02 bank 1, manifold vacuum, water temp, short term fuel trim 1, and as listed fuel flow.

One is after starting it when it sat for just under 3 hours, the other after driving about 20 minutes.

https://imgur.com/a/7Q8SZ

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post #14 of 37 Old 03-02-2018, 12:01 AM
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I had been thinking it would be more important to see the readings as the problem started happening during startup. But in looking a what you posted, those vacuum readings look way too low, almost like they're actually PSI instead of in/HG. But if those values are correct, it would be likely there's a vacuum leak - perhaps something the body shop didn't reconnect correctly, or accidentally damaged.

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post #15 of 37 Old 03-02-2018, 09:31 AM
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I would say vacuum looks OK.
@kiaguy007 , those are at idle (fuel flow is minimal), also this being MT there is no load to the engine.
I have a mechanical boost gauge. At idle it gets to about -12 to -10, when coasting in gear I can reach as low as -20 in Hg.

20 minutes trip so the engine must have been hot enough to allow all power. Until coolant is at at least 70 deg C (operating temp is 82) ECU limits boost and how quickly the boost builds up. At anything below 50 deg C you barely get 5 psi... even with tune

What I find weird is the AFR being stoichiometric...

Anyway, since you have Torque running, upload your log file to http://datazap.me/
For some more info, you can read here: https://torque-bhp.com/

Get AFR, coolant temp, boost, ignition (timing), throttle position (you can do both: pedal and throttle - sometimes they differ...), RPM, and car speed (from ECU).

When you floored it for the first time, did you hear any knocks, did a cloud of smoke appear?
I noticed in mine that if I do not push it from time to time and keep driving it civil (how can you drive it civil for too long?) meaning gentle shifts, half throttle, then when I push it at some point it may hesitate. I "clear" it a few times and it somehow goes fine.
I am thinking it could be something related to oil getting from PCV. You had the car sitting for long, plus it is cold.
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