Hyundai Forums banner

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.
 
#102 ·
Thanks for the reply. I almost always start up and go without waiting. I tried the gas pedal solution on the first page of this thread yesterday, but the problem returned this morning. It seems to occur randomly - one red light the car will be silent and the next I will feel noticeable vibrations. Turning off A/C helps (but not a solution given 95+ degree FL weather) so I've been putting the car in N when idling which stops the vibrations. I'm planning to take the car into the dealership next week to see if there could be a possible computer fix.

BTW I also have a titanium gray GLS. Could it be a problem from a common source? My car was made in Ulsan, S. Korea.
 
#106 ·
Not sure if this is related, but I've got a 2012 Elantra with 250 miles on it. A/T. Only had it 11 days. Started it this morning and noticed it was idling kind of rough before I put it in gear. Yes the A/C was on, turned it off and no difference. Hoped it was my imagination. Put it in reverse, and by the time we got to the end of the drive way and i put it in drive it had died. WTH? Seemed like it was not getting gas like it was supposed to? Turned everything off, then on and it was fine afterward. Anyone else experience this?
 
#107 ·
QUOTE (DR in TX @ Aug 31 2011, 10:58 AM) index.php?act=findpost&pid=497804
Not sure if this is related, but I've got a 2012 Elantra with 250 miles on it. A/T. Only had it 11 days. Started it this morning and noticed it was idling kind of rough before I put it in gear. Yes the A/C was on, turned it off and no difference. Hoped it was my imagination. Put it in reverse, and by the time we got to the end of the drive way and i put it in drive it had died. WTH? Seemed like it was not getting gas like it was supposed to? Turned everything off, then on and it was fine afterward. Anyone else experience this?
Maybe let it warm a bit longer.

mechanics don't know how to fix cars today if no computer around, the engines are now all computer controlled sensors and selenoids. Problems now are electronic, not mechanical lol
 
#108 ·
QUOTE (DR in TX @ Aug 31 2011, 10:58 AM) index.php?act=findpost&pid=497804
Not sure if this is related, but I've got a 2012 Elantra with 250 miles on it. A/T. Only had it 11 days. Started it this morning and noticed it was idling kind of rough before I put it in gear. Yes the A/C was on, turned it off and no difference. Hoped it was my imagination. Put it in reverse, and by the time we got to the end of the drive way and i put it in drive it had died. WTH? Seemed like it was not getting gas like it was supposed to? Turned everything off, then on and it was fine afterward. Anyone else experience this?
Could be a defective crankshaft sensor, but there's no point speculating. I'd get it down to the dealer to see if there's an error code (and a quick fix under warranty).

Normally I'd ignore an electronic glitch on the first occurrence, but not when it involves engine stalling.
 
#109 ·
QUOTE (DR in TX @ Aug 31 2011, 07:58 AM) index.php?act=findpost&pid=497804
Not sure if this is related, but I've got a 2012 Elantra with 250 miles on it. A/T. Only had it 11 days. Started it this morning and noticed it was idling kind of rough before I put it in gear. Yes the A/C was on, turned it off and no difference. Hoped it was my imagination. Put it in reverse, and by the time we got to the end of the drive way and i put it in drive it had died. WTH? Seemed like it was not getting gas like it was supposed to? Turned everything off, then on and it was fine afterward. Anyone else experience this?
Our 2012 GLS Automatic developed a rough idle problem out of the blue at around 600 miles. The rpms would drop so low that the car would die. It finally threw a "check engine light" and the dealer was able to determine that it had a bad Oil Control Valve ( OCV ). They overnighted in the part, made the replacement, and no problems since. Let us know what you find out.
 
#110 ·
I'd like to ask that people posting complaints about rough idling be more clear about what they are experiencing. Vibrations do not necessarily indicate rough idling. Some vibrations at idle are normal. The owner's manual says so and gives some causes for this. ESC, for example, if I remember correctly. I think the A/C compressor and some other motorized parts can cause it, too. But I wouldn't call that a rough idle. When engine RPM is unsteady, that to me is a rough idle and indicates service is needed.
 
#111 ·
QUOTE (Egregius @ Sep 1 2011, 02:41 PM) index.php?act=findpost&pid=498381
I'd like to ask that people posting complaints about rough idling be more clear about what they are experiencing. Vibrations do not necessarily indicate rough idling. Some vibrations at idle are normal. The owner's manual says so and gives some causes for this. ESC, for example, if I remember correctly. I think the A/C compressor and some other motorized parts can cause it, too. But I wouldn't call that a rough idle. When engine RPM is unsteady, that to me is a rough idle and indicates service is needed.
Sometimes the car vibrates a lot more than normal while the car is in D at a stop light or similar situation. It is enough that a passenger in the car has noticed. Recently I had my OBD2 device and torque app running when it happened and the RPM is normal during this. If this is an indicator of a larger problem then it will certainly come to light before the warranty is up. This could be anything or simply just a quirk of the car.
 
G
#112 ·
I have this problem as well and I have only noticed it happen while stopped at a traffic light, foot on the brake pedal, trans in drive, with the ac on. The car has been running for some time and is up to normal opperating temps. It is not what I would call a vibration. It is more of an mild engine studder or stumble. I would refer to it as an idle problem. Its not rough enough that the car stalls out, but it is very noticable. I had one occurance a few months back were the car did stall out after a cold start, I started the car, immediately put it in drive, and pressed the gas, didnt even make it out of my parking space. I took it straight to the dealer and they downloaded a new program update to the onboard computer and it has not stalled out since. I honestly cannot remember if it had this rough idle problem before the reprogramming. It is my understanding that this 1.8 is an all new engine and maybe Hyundai has not got all of the programming glitches taken care of. Or it may just be the accessory load on the engine. Maybe its just the way this engine performs and I am not use to it yet. Only time will tell i guess.
 
#113 ·
QUOTE (DR in TX @ Aug 31 2011, 10:58 AM) index.php?act=findpost&pid=497804
Not sure if this is related, but I've got a 2012 Elantra with 250 miles on it. A/T. Only had it 11 days. Started it this morning and noticed it was idling kind of rough before I put it in gear. Yes the A/C was on, turned it off and no difference. Hoped it was my imagination. Put it in reverse, and by the time we got to the end of the drive way and i put it in drive it had died. WTH? Seemed like it was not getting gas like it was supposed to? Turned everything off, then on and it was fine afterward. Anyone else experience this?
Our car stalled while driving slowly in a parking lot, waiting to get onto the main road. Restarted fine like yours, and took it to dealer and nothing found. At least it's documented in case it starts happening more often. Just hope it never happens when I try to zip out of a driveway into fast traffic. Environmental conditions: 113 degrees ambient temp, AC on level 4 max recirc on.
 
#114 ·
QUOTE (Egregius @ Sep 1 2011, 03:41 PM) index.php?act=findpost&pid=498381
I'd like to ask that people posting complaints about rough idling be more clear about what they are experiencing. Vibrations do not necessarily indicate rough idling. Some vibrations at idle are normal. The owner's manual says so and gives some causes for this. ESC, for example, if I remember correctly. I think the A/C compressor and some other motorized parts can cause it, too. But I wouldn't call that a rough idle. When engine RPM is unsteady, that to me is a rough idle and indicates service is needed.
My RPMs aren't fluctuating, but to me, if the vibrations are more apparent than other cars in its class it's an issue. This is my first Hyundai, but I don't remember having this issue with an '07 Corolla or my '98 Accord.
 
#116 ·
YES ! My 2011 Elantra does the exact same thimg ! It's totally intermittant ! It's not a full mist because when you excellerate after stopping you feel no issues.

Although Today mine had a TOTAL MISS, when I started and the engine light came on. When I stopped the car. When I tried to turn it back on, It would not even start at all! I let it sit a few minutes and it started right up like nothing happened. I posted this in detail. Also, do you notice that when you start your engine that there is a slight valve tap for about 2 seconds. I am noticing this.
 
#117 ·
QUOTE (mikerog60 @ Sep 6 2011, 09:52 AM) index.php?act=findpost&pid=500030
YES ! My 2011 Elantra does the exact same thimg ! It's totally intermittant ! It's not a full mist because when you excellerate after stopping you feel no issues.

Although Today mine had a TOTAL MISS, when I started and the engine light came on. When I stopped the car. When I tried to turn it back on, It would not even start at all! I let it sit a few minutes and it started right up like nothing happened. I posted this in detail. Also, do you notice that when you start your engine that there is a slight valve tap for about 2 seconds. I am noticing this.
If your check engine light came on and the car died then I would say there was a bigger problem than we are discussing. Yes there is a little engine noise on startup but there is on all 4 cylinder DOHC cars.
 
#118 ·
We are experiencing the same problem
2012 limited with automatic Canadian edition, made in Alabama
we have had it for 3 months now and it started doing it less than a month ago, it has only done it about 5 times, and only once while i was driving. same conditions as others describe, car is warm, had been driving for a while, come to a red light in D with foot on the brake and it starts to idle rough which causes vibration. The rpm needle jitters up/down and slightly below a normal idle which tells me it could be close to a stall. had it in for service 2 today at 9500km, we mentioned it to them but there were no error codes and they couldn't replicate the problem so they didn't do anything about it. This kinda pisses me off like others have mentioned. nobody is a mechanic anymore they just know how to replace a part if an error code comes up. someone mentioned that its not mechanical problems these days but rather electric. i disagree, i still think there are mechanical problems but if an electric sensor doesn't pick up on the mechanical issue then its not fixed. not to say that there arn't electrical-only problems. I was also pissed off because service 2 includes tire rotation but they didnt rotate my tires. i know this because my special wheel lock socket had no tool marks on the left side of the edges, other than the marks to install the wheel locks which are on the right side of the edges. but bad/poor mechanics is a different issue. my wife said after she picked up the car today she experienced the problem again on the way home and she had the air completely off with the windows down. so i don't think it is the a/c's problem but it may contribute to the extra load at idle. This OCV seems like it may be the problem. hopefully more feedback can be contributed about this solution. or others if they are found. i just hope this doesn't drag on till the warranty expires then they magically find the solution.
 
#120 ·
i just hope this doesn't drag on till the warranty expires then they magically find the solution.
I suspect that the shaky idle some of us experience is related to the ultra-lean fuel mixture the engineers programmed into the car in the name of high MPG and low emissions. It might be the new normal for awhile, just like knocking and pinging was "normal" in the early days of unleaded fuel and emissions controls in the 1970s and 80s.

At least this time there is the possibility of a free software upgrade someday addressing the issue. But either way, it really is no big deal. The fact that it's getting this much attention is proof of how spoiled we've become as consumers.
 
#121 ·
I have a 2011 4 cyl Santa Fe, 32,000 miles and it also idles rough in D. I have only owned the car for 4 months, but I have started to notice this rough idle. My wife has a 2009 V6 Santa Fe and it's as smooth as glass whether in gear or out.
Would be nice to find a solution to this problem. It's not just one model of car either. Seems like it's 4cyl engines.
 
#128 ·
From my understanding and research on this Elantra I believe the rough idle is caused by the "smart" alternator. I will explain.

The "Smart" alternator is used to keep engine drag down to conserve fuel. It senses load on the electrical system and kicks on and off as needed. Kinda like the A/C compressor.

So my guess is when your at a stop, or braking to a stop, the electrical load increases creating a need for the alternator to kick on causes a drop in RPM just slight enough to cause the engine to act a little rough.

Just my ten cents.

Jeff
 
#129 · (Edited)
:trophy:

That's the best educated guess I've heard yet about why the condition is so random and sporadic. Wish I'd thought of it first. :)

It makes sense that the shaking is noticed at idle only occasionally, because most of the time the smart alternator should not be charging at idle. Next time I notice the shaking I will try to take note of how much city driving I've been doing under heavy electrical load, ie: morning commutes to the kids' school with the seat warmers and rear defroster turned on. Betcha anything that's when the shaking is most likely to occur.
 
#130 ·
A little research and the (ECR) valve (exhaust gas recirculation) could have some vacuum problems or maybe some carbon from the exhaust which is recirculated for emissions. I may have to bring it into the dealer and see what happens. At my last oil change, first one for me with this car, they said it was normal when you put it in drive. I call BS. There should be no difference between neutral and drive.
 
#137 ·
That is exactly what I get most of the time. P or N and its smooth as glass. Put it in gear and it's rough. I have 32,000 miles and it's a 4cyl. I may take it in next week and see if they can pin point the problem. My wife's 09 Santa Fe makes no difference at all, in gear or out, you can't notice any difference. A friend of ours has a new Sonata and it isn't rough either.
 
#140 ·
Jeff, I understand there is a small drop in RPM between N and D, but there should not be any rough idle. You can't even feel a clunk or anything when going from N to D. I am too old and have owned too many cars to know this is not the norm. If Hyundai made all their cars this way and told people it was normal, they would go out of business, no one would buy one.
My wife has an 09 Santa Fe and there is no difference between N and D.
I need to make an appointment and take it in. My friends with their Fords and Chevys rag on me because of the idle. I got to get it fixed. LOL
 
#141 ·
Jeff, I understand there is a small drop in RPM between N and D, but there should not be any rough idle. You can't even feel a clunk or anything when going from N to D. I am too old and have owned too many cars to know this is not the norm. If Hyundai made all their cars this way and told people it was normal, they would go out of business, no one would buy one.
My wife has an 09 Santa Fe and there is no difference between N and D.
I need to make an appointment and take it in. My friends with their Fords and Chevys rag on me because of the idle. I got to get it fixed. LOL
Honestly, I don't think there is a fix. My car has always idled off and on kinda rough. You factor in the use of the smart alternator (of which my friends ford focus has and idles just as bad by the way) and I think its just a trait of the car. Now if your car is idleing like it is running all 3 cylinders than by all means better investigate, but you could just be using poor quality gas, moisture in your fuel system, or possible a defective coil pack. Try the dealer if you have not already done so and go from there.

on my Elantra, I purchased it used, and it had a rough idle, so I changed the spark plugs, check the coil packs, of which 2 coil packs were loose so I tightened those, changed the pcv valve because it looked like it was toyed with and it ran much better. All and all though, the car has never been silky smooth. Im getting good MPG's so if there was something really wrong, either a check engine light would come on, or the MPG's would go way down. Throw in all the factors and there is not much to guess from. If you figure something out, let us all know...heck could be a bad engine mount, who knows??

Jeff
 
Top