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Rough Idle

155K views 231 replies 73 participants last post by  robertkoa 
#1 ·
My 2011 Elantra has a slightly rough idle at stop lights. It doesn't happen ever time, and some people probably wouldn't even notice it, but at every few/several stops it idles a bit rough. When I recently had it in to Hyundai service for the ECM update, I asked them to take a look at it. Of couse, they couldn't replicate it at the time, so they couldn't do anything to address it directly. The service manager asked if it happens when the A/C is on or off. While I didn't know the answer at the time, it seems to happen with it both on or off. He did say that the ECM update may address/fix the issue, but unfortunately it didn't. While it's not a big problem, it's a minor annoyance I'd like to get fixed (as I need to enjoy my ride at all times ^_^ ).

Anybody else notice this with their car and, if so, have you done anything about it? Any other suggestions are welcomed - especially from those who understand what causes the car to idle like that.
 
#2 ·
Mine too, happens when the ac is on or off intermittently at stoplights I haven't bothered to take it in yet since I dont want my car to end up as a testbed since this is a very minor problem. It started doing it less when I switched to synthetic oil but for now my solution is to drop the car into N at a light. I'm thinking there may be a bad iacv, or maf, also possibly a motor mount or a minor vacuum issue.
 
#3 ·
I've had a slight noise also that doesn't happen all the time. Someone on here mentioned that the Oil Control Valve is loud on these motors and that might be the culprit. I've only had mine for 3 1/2 weeks and have not taken it back in for the ECM update. Did you notice a difference in the way the car shifts after the ECM update?
 
#4 ·
I too just had my 11 limited in the service bay for the excat same issue. Odd thing was there was a GLS there for the excat same thing. I spoke to the tech and he made a report on it and hopefully if more would take them in for the issue Hyundai will look deeper into it cause, even the mechanic told me it shouldnt do the rough idle thing. He told me it seemed as if the idle control doesnt account for the a\c sometimes.

So I would recommend that anyone that has this issue take it in so the paper trails start and Hyundai sees there might be a small issue here that justs needs a tweak.
 
#6 ·
QUOTE (NPMountaineer @ Apr 29 2011, 11:31 AM) index.php?act=findpost&pid=437750
Did you notice a difference in the way the car shifts after the ECM update?
Yes, it reacts instantly now, rather than having a 1/2 second lag when you initially "step on the gas." So it's much more responsive now. Haven't noticed any real differnce in how the transmission shifts once "at speed" though. Then again, I never noticed any issue as far as that's concerned. If your car is included in the ECM Update TSB Campaign production date range, I would suggest getting it done.
 
#8 ·
I've noticed an occasional shaking at idle too... more than I would expect from a small 4-banger. I suspect it's triggered by the A/C cycling on and off, but cannot say for sure.

PS: Someguy, I haven't noticed any difference since switching to synthetic.. nor would I expect any.
 
#9 ·
QUOTE (ImKramer @ Apr 29 2011, 11:01 AM) index.php?act=findpost&pid=437734
My 2011 Elantra has a slightly rough idle at stop lights. It doesn't happen ever time, and some people probably wouldn't even notice it, but at every few/several stops it idles a bit rough. When I recently had it in to Hyundai service for the ECM update, I asked them to take a look at it. Of couse, they couldn't replicate it at the time, so they couldn't do anything to address it directly. The service manager asked if it happens when the A/C is on or off. While I didn't know the answer at the time, it seems to happen with it both on or off. He did say that the ECM update may address/fix the issue, but unfortunately it didn't. While it's not a big problem, it's a minor annoyance I'd like to get fixed (as I need to enjoy my ride at all times ^_^ ).

Anybody else notice this with their car and, if so, have you done anything about it? Any other suggestions are welcomed - especially from those who understand what causes the car to idle like that.

i can honestly say that while i am stopped at the lights, if i dont have my fan on, my car is so quiet that it feels like its not running :grin:
 
#167 ·
QUOTE (Joemidnight @ Apr 29 2011, 03:24 PM) index.php?act=findpost&pid=437838

+1. When I first got the car, I turned the ignition and was like "WTF? Why isn't it turning on???" LOL
I had mine, an 03 at 98K miles, same story, I didn't really maintain it well until about 70K Miles, that's when I put her into baby mode realizing what a durable 4-banger I was dealing with.

If anyone comes across a used Elantra from 03-Present, and it idles high/rough, or is rough/loud and uncomfortable while accelerating, it's most likely a rollback car (odo) or was severely beaten on the gas pedal, and never maintained.

Makes me sick seeing dealers trying to charge anything near 8-10K for the same car I drove nearly 3 years ago with half the amount of miles in 10 times worse mechanical and aesthetic conditions.

I wonder if tougher sub-zero radiators can be installed, like -50 or -60 ones instead of -20.
 
#11 ·
QUOTE (Don67 @ Apr 29 2011, 02:09 PM) index.php?act=findpost&pid=437827
I've noticed an occasional shaking at idle too... more than I would expect from a small 4-banger. I suspect it's triggered by the A/C cycling on and off, but cannot say for sure.

PS: Someguy, I haven't noticed any difference since switching to synthetic.. nor would I expect any.
Yeah the less shaking since switching to synthetic thing is possibly all in my head
 
#12 ·
Just got back from an errand, and there is definitely something odd going on. Sometimes the steering wheel is visibly shaking at idle, even with the A/C off. But other times it runs smoothly even with the A/C on.

I'm a bit surprised by some of the comments above about people being fooled into the thinking the car is turned off. My Elantra has never idled that smoothly... the seatback and floorpan are constantly throbbing, as if to remind me that this is no Santa Fe. Maybe that ECM update will help.
 
#13 ·
I have noticed this rough idle too. I thought maybe it was the A/C, but it also does it with it off. I was thinking about bringing it in for this issue. It seems that the RPMs drop really low and that is when I notice it. I am glad I am not the only one to notice this.

How do I know if I need the ECM update?
 
#14 ·
A couple of questions for the people describing the the rough idle symptom

1) Auto or Manual Transmission?

2) Is the symptom the same w/ the car in neutral and/or w/ clutch pedal depressed?

3) Don67 mentioned vibration in the steering wheel. Is this where everyone is experiencing the sensation of rough idle or is it just a sound (vs vibration) thing to some people?

@Don67 specifically is the feeling from the steering wheel a true vibration (as in it's vibrating in all directions) or is it like the wheel is trying to turn a tiny bit back and forth super fast?
 
#15 ·
QUOTE (skyblue @ Apr 29 2011, 04:28 PM) index.php?act=findpost&pid=437865
How do I know if I need the ECM update?
See attached.

I've emailed my local service manager and will try to have this done soon. If it is not the cause, however, something tells me there will be a separate TSB given that several of us seem to be reporting identical symptoms.
 

Attachments

#17 ·
QUOTE (CopaMundial @ Apr 29 2011, 03:45 PM) index.php?act=findpost&pid=437871
A couple of questions for the people describing the the rough idle symptom

1) Auto or Manual Transmission?

2) Is the symptom the same w/ the car in neutral and/or w/ clutch pedal depressed?

3) Don67 mentioned vibration in the steering wheel. Is this where everyone is experiencing the sensation of rough idle or is it just a sound (vs vibration) thing to some people?

@Don67 specifically is the feeling from the steering wheel a true vibration (as in it's vibrating in all directions) or is it like the wheel is trying to turn a tiny bit back and forth super fast?
Auto trans
Goes away in N or P - simple solution for now drop to N at a light
Vibration is felt in whole car no sound but occasionally you can feel in wheel similar to what you may experience with a bad motor mount

I'm sure this will get resolved soon just one of the minor issues you may run across with a brand new redesigned car and a minor annoyance at best.
 
#18 ·
QUOTE (someguy @ Apr 29 2011, 05:24 PM) index.php?act=findpost&pid=437886
Auto trans
Goes away in N or P - simple solution for now drop to N at a light
Vibration is felt in whole car no sound but occasionally you can feel in wheel similar to what you may experience with a bad motor mount
So one more question would be if you're at a stop, in gear, with foot on brake and the car is shaking... will it stop if you simply let off the brake and start rolling @ idle speed or does it continue to shake until you press on gas to raise the revs? (ypu'll obviously have to test this when no one is behind you waiting to go)

Ok, I lied when I said one more question.
Also if it's shaking and you put the car into Neutral have you noticed if there is a change in the idle engine speed (ie are you at higher or lower RPM when in Neutral vs the shaking symptom)?
 
#20 ·
CopaMundial good question I think it goes away with foot off brake i usually just drop to N at lights since i read its better for fuel economy anyhow. I dont notice much change in rpm in idle between D or N or with AC on or off.
 
#21 ·
The rough idle/vibrations when in D can be the motor under load and being held by the brakes. The car is in gear and wants to move, but cant because the brakes are holding it. In motion, P, or N, the motor isnt really under any load and is running freely.

If there was an issue with the idle, wouldnt it do it all the time and it would probably be more noticeable in N then in gear.
 
#22 ·
QUOTE (CopaMundial @ Apr 29 2011, 04:45 PM) index.php?act=findpost&pid=437871
@Don67 specifically is the feeling from the steering wheel a true vibration (as in it's vibrating in all directions) or is it like the wheel is trying to turn a tiny bit back and forth super fast?
The steering wheel shakes visibly (no turning), while a heavy vibration is felt throughout the interior. Even passengers have commented.

It acts up randomly while stopped in "D", maybe 10% of the time. It does not appear correlated to A/C activity or anything else. I'm stumped.
 
#25 ·
We also have this, intermittently. Parked in the driveway today and in Park, looked under the hood...the engine shakes visibly. Almost like a bad harmonic balance or something. It's been a looong time since we had a 4 banger, so not sure how normal this is. When in Drive gear, we feel it only intermittently and with AC on.
 
#26 ·
QUOTE (Don67 @ Apr 29 2011, 04:46 PM) index.php?act=findpost&pid=437872
See attached.

I've emailed my local service manager and will try to have this done soon. If it is not the cause, however, something tells me there will be a separate TSB given that several of us seem to be reporting identical symptoms.

you're welcome to come drive to toronto if you'd like to witness smooth idling :)

actually from what a few others have pointed out... I do drive manual, that COULD be the difference :)
 
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