Engine Stumbling - misfiring - Page 2 - Kia Forte Forum : Sedan / Koup / Forte5 Forums
User Tag List

 5Likes
Reply
 
Thread Tools
post #16 of 37 Old 03-02-2018, 10:26 AM
Senior Member
 
Join Date: May 2014
Posts: 853
Thanks: 19
Thanked 87 Times in 82 Posts
Quote:
Originally Posted by PLP View Post
I would say vacuum looks OK.....
I'm not that familiar with the second gen, and didn't realize (until I just checked), that the only engine option for the SX is a turbo. So, being boosted, I'm sure you're right about the vacuum readings. Guess I need to be more careful about making comments about stuff I'm less familiar with

2011 SX 2.4L (thankfully MPI) A/T 130K
kiaguy007 is offline  
Sponsored Links
Advertisement
 
post #17 of 37 Old 03-02-2018, 11:05 AM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
Quote:
Originally Posted by kiaguy007 View Post
I'm not that familiar with the second gen, and didn't realize (until I just checked), that the only engine option for the SX is a turbo. So, being boosted, I'm sure you're right about the vacuum readings. Guess I need to be more careful about making comments about stuff I'm less familiar with
No worries. But even with NA, the vacuum could reach almost "pure vacuum" in coasting that is about -22 in Hg. I bet he used boost type gauge that translates boost into psi, while vacuum into in of Hg.

You see, SX models get 1.6T but only for hatchback (F5) and Koup. In Sedan version you can get LX, EX, and S... but all of them are NA engines. And it is different for Canada...

So yeah, it can be misleading, especially that previous gen SX was 2.4 NA.

But chime in anytime you have an idea. It is very easy to get off the track and to get affixed on a wrong one...
PLP is online now  
The Following User Says Thank You to PLP For This Useful Post:
kiaguy007 (03-02-2018)
post #18 of 37 Old 03-02-2018, 11:47 AM
Senior Member
 
Join Date: May 2014
Posts: 853
Thanks: 19
Thanked 87 Times in 82 Posts
Just an editorial comment that it's nice to see someone with professional expertise show up here and be willing to give free advice to others. It's too bad that these auto forums have so little DIY activity going on these days, resulting in quality members dropping out of boredom. My understanding is that just about all of the DIY has moved to social media (which I don't care to use). But anyway, glad to have you aboard for however long you chose to stay
PLP and ragnabrok like this.

2011 SX 2.4L (thankfully MPI) A/T 130K
kiaguy007 is offline  
Sponsored Links
Advertisement
 
post #19 of 37 Old 03-03-2018, 01:21 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
OK, first of all thanks to you awesome people for sticking around in this thread!

Ran torque yesterday with screen recording. Same monitors as the previous pictures.

First up, cold start. Left it overnight and fired it up. you can't hear or see it, but it's intermittently shaky, Everything is turned off, radio, HVAC, heated anything.
https://youtu.be/lJIKoTw7M88

Next we have on the highway after ~30 minutes of driving. holding 110 km/h with cruise control in 6th.
https://youtu.be/CoZAtEchQI4

and also after about 30 mins of driving, turning onto the highway, pulling 3rd gear from ~30 KM/h to ~110, pedal as far down as i can mash it.
https://youtu.be/Ln-udQqQCcg

And you are right, it does go from in/Hg to PSI from vacuum to boost.

Last edited by ragnabrok; 03-03-2018 at 01:23 PM. Reason: clarify
ragnabrok is offline  
post #20 of 37 Old 03-05-2018, 12:58 PM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
A few things.
I can hear troubles at 0:26 - look on fuel flow and AFR. It is very hard trying to get it in shape, but struggles. It did not die, lie last time.
What worries me is the vacuum reading. You had it at -19.2 in the other screen while on the main it is -9.5 (about 1:50).
Besides, mine when start reads about 0.00 for vacuum/boost until rpm drops a bit and I can hear the BOV venting a lot. Can you hear that too? It does not seem to be doing it.
Then, later on it runs relatively fine, I would say. Definitely the switch from cold oxygen sensor to hot (open closed loop).

Take the video to the dealer.


As for the rest.
Steady sounds OK

Under WOT (wide open throttle) I see weird things.
You do not reach stock boost that should be about 18 psi max. Sure, most of the time I would be hitting 16, but you barely hit 14 psi in mid range. It tapers off in higher band, but the low end should be 16-18 psi under metal to metal.


I assume you are the first owner, right? No parts were changed?
PLP is online now  
post #21 of 37 Old 03-05-2018, 02:03 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Yup, first owner. The only thing not from the factory in this car is the gas, oil and air filter, though the air filter is OEM. It's completely stock.

It's in the dealer right now, and I've given all the info I have, videos included.

Good catch on that other vacuum gauge, I'll compare that when I get the car back.
ragnabrok is offline  
post #22 of 37 Old 03-05-2018, 02:41 PM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
I forgot to say that - fuel flow. See when it switches from about 4 l/h to 2 l/h? (gallon/hour)
That is the very moment it is stumbling. But why would it still show measured AFR being 14.5? No clue... it should not read anything until the sensor is hot, or get the more true reading of very rich on cold.

Please update what the dealer said.
PLP is online now  
post #23 of 37 Old 03-05-2018, 04:55 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Well, at least this dealer took it inside. I'm told they removed the spark plug wires and looked at the coils. They apparently found standing water in the plug wells, and dried them out. Other than that they confirm it had error codes, but currently doesn't and is running fine. No vacuum issues, normal fuel consumption. mm hmmm...

Changed the units in torque to metric, and have the vacuum always in PSI, not convert to in/hg when in vacuum, and it warm idles at ~ -9 PSI, and in a spirited 3rd gear pull did hit 16 PSI boost.

It's supposed to drop to -12C tonight, so i'll check the vacuum again with a cold start, i'll also have some 100km+ highway driving on thursday and can check consumption again, but i get the feeling there hasn't been standing water in the plug wells since december.
ragnabrok is offline  
post #24 of 37 Old 03-06-2018, 11:20 AM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Ok 2 more. For reference, this is the OBD2 reader i'm using http://a.co/7VKKnna along with torque pro.

Added air/fuel mix commanded, and switched the vacuum to stay in PSI instead of convert to IN/hg. The dial that was reporting -19.5 when the others were at -9 seems to be an anomoly, it was the only one that didn't match the others.

Cold start - https://youtu.be/p6u9T24LpvU - around -10 C with the window open, and again, no hvac or radio or heated seats on.

Vacuum doesn't sit at 0, nor do i really hear a bov venting at any point. the commanded air/fuel mix stays pretty rich. near the end of the video i get out and walk around to the exhaust.

warmish start - https://youtu.be/4hQEsgbDjsY

basically stopped the engine after the previous video for 30 seconds and started it again. idle RMP lowered, at 50+ C it should be warm enough to run at 14.7:1 air/fuel, no?
ragnabrok is offline  
post #25 of 37 Old 03-06-2018, 12:04 PM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
Quote:
Originally Posted by ragnabrok View Post
They apparently found standing water in the plug wells, and dried them out.
How long have you been driving with this damage before getting the car fixed?
Also, do you have the engine cover on? I cannot say from the pictures.

The standing water explains a lot. That was the problem.
It was purely misfiring. I had this happened to my other car, but that was after I washed engine... and sprayed too much of water on it.

I guess in your case, if you were driving it for a while you could have scooped some water/snow and got it condensed there. Also, the body shop could have washed the engine or left the hood up.


AFR now is much lower, which is more normal.
Still vacuum is different, but what fuel do you use? Regular 87 octane? Yet, that is not something I would worry about too much.

You hit 16 psi, that means engine is fine.


Quote:
Originally Posted by ragnabrok View Post
at 50+ C it should be warm enough to run at 14.7:1 air/fuel, no?
Nope, you would not be hitting 14.7. Turbo'ed cars run rich, meaning below 14.6. According to tuner they run at 12... which I find weird because none of my logs supported that.
I will dig into it at some point.


EDIT:

A cold start, kind of cold - after about 7 hours sitting outside at about +4 deg C. Engine is at about +10 deg C.
There is a background noise from the building behind, but you can clearly see the boost gauge staying at 0 (give or take a few psi) and dropping to deep negative side at about 0:45.
I pushed the gas a few times in between (quick tap) to show how the pressure changes.

https://youtu.be/6BZ05Qwh5O4

I found some older one with very cold start. You can hear the BOV venting as well.

https://youtu.be/7a1sf3PSw7w

Last edited by PLP; 03-06-2018 at 03:27 PM.
PLP is online now  
post #26 of 37 Old 03-06-2018, 03:58 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Quote:
How long have you been driving with this damage before getting the car fixed?
Also, do you have the engine cover on? I cannot say from the pictures.
The first time the CEL came on, and it rattled like in the first video, i made a service appointment. they got me in a few days later. The engine cover is on, the only time i've seen it come off is when one of the service guys popped it off to look at the connections.

Quote:
Still vacuum is different, but what fuel do you use? Regular 87 octane? Yet, that is not something I would worry about too much.
yeah 87.

Odd, before the 2nd dealer claimed to have discovered the water, it was 14.7:1 AFR in all the videos.

I took it on the highway today, and some conspiracy level stuff is going on now. In the city, the L/100km guage very closely matches the fuel flow. At highway speeds however, it differs dramatically, with the car display being much lower.

at 100/KMH, with cruise on, on flat road, the car displays ~7L/100KM, both the instant, and if i reset the average. The OBD reads 10-11 (it bouces around)
at 115 km/h, with cruise on a flat road again, car displays 8-9. OBD reads 12-13.

https://imgur.com/a/Qli4d Pictures taken one after the other.

Maybe coincidental, but seems like they heard my complaint of bad fuel economy, and fudged it so at least the display shows a more pleasing number. But it's showing better fuel efficiency than it was achieving last summer.

I haven't washed my engine, and I dont think the body shop did either, there were still leaves lower in the engine bay.
ragnabrok is offline  
post #27 of 37 Old 03-06-2018, 04:34 PM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
Quote:
Originally Posted by ragnabrok View Post
The first time the CEL came on, and it rattled like in the first video, i made a service appointment. they got me in a few days later.
I meant the accident... how long it took before you left the car with the body shop. I am just thinking if snow somehow did not find a way into the engine bay through missing fog light.

Quote:
Originally Posted by ragnabrok View Post
at 100/KMH, with cruise on, on flat road, the car displays ~7L/100KM, both the instant, and if i reset the average. The OBD reads 10-11 (it bouces around)
at 115 km/h, with cruise on a flat road again, car displays 8-9. OBD reads 12-13.

The instrument cluster gauge shows fuel economy in liters/100 km, while Torque displays fuel flow, in liters/h. Also, my calculations show that the cars gauge is about 10% off, using USA units. Not sure if that would translate into 10% in metric, the only correct, units. Car shows say 7 l/100 km, while the real one is 7.7 l /100 km.

So, at 115 km/h you get say 8 l/100 km, while fuel flow is 12 l/h. That means in one hour you use 12 l to drive 115 km, 12/115*100=10.4 l/100 km.
Torque uses weird algorithm and it was way off in my car, too. It would show very inaccurate numbers.


Did you see my start videos? Have you ever heard this sound?
PLP is online now  
post #28 of 37 Old 03-06-2018, 07:02 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Quote:
Originally Posted by PLP View Post
I meant the accident... how long it took before you left the car with the body shop. I am just thinking if snow somehow did not find a way into the engine bay through missing fog light. Did you see my start videos? Have you ever heard this sound?
It was about 2 weeks from smash to the car going in the bodyshop. This was mid october, and there wasn't any snow on the ground yet. It sat in said bodyshop for 2 months waiting on the backordered washer fluid resevoir. I got the car back Dec 22nd, and noticed the stumbling on the 29th, the check engine light came on the 31st.

I hear the sound in your video, but have never heard my car make it.
ragnabrok is offline  
The Following User Says Thank You to ragnabrok For This Useful Post:
PLP (03-06-2018)
post #29 of 37 Old 03-06-2018, 10:24 PM
PLP
Super Moderator
 
PLP's Avatar
 
Join Date: Mar 2016
Location: East Lansing, MI
Posts: 437
Drives: 2016 KIA Forte5 SX A/T
Thanks: 5
Thanked 12 Times in 12 Posts
Quote:
Originally Posted by ragnabrok View Post
I hear the sound in your video, but have never heard my car make it.
Bizarre. Then is it mine that is bad then? Is there anything different in Canadian version?

As for water - it must have gotten then somehow...
As for error itself - it could have taken a while to get it to the state it started having issues. I drove for a week without a big problem until just that day. Sure, car seemed weird a bit, but not so bad at all. I blamed petrol.

Glad it is OK now. Lets give it a few days and if it's OK, I guess you are good for now.
PLP is online now  
post #30 of 37 Old 03-06-2018, 10:50 PM Thread Starter
Newbie
 
Join Date: Aug 2016
Posts: 20
Drives: Forte5
Thanks: 1
Thanked 1 Time in 1 Post
Seems to be, i don't trust it though. Maybe i'm just scrutinizing it too much now, every sound it makes.
ragnabrok is offline  
Reply

Bookmarks

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off