[hyuni30]

Hi guys, been lurking this forum for a while now but finally need some advice ..

I have a 2013 1.6 CRDi Blue Drive Edition i30 on 60,000 miles. Recently I have been noticing a very subtle (but very definite) pulsing when the car is stopped and in idle. Not every time I stop but often. You can see the RPM bouncing up and down very slightly on the tachometer but the pulsing is most noticeable with a foot on the footbrake. I haven't had any warning lights on the car and otherwise the performance is fine. I typically fill up with the bp ultimate active diesel when I can or the bp regular diesel if not but I did use supermarket fuel recently and the car has been worse since.

I'm not extremely mechanically minded so won't trouble you for particularly in depth details but does this sound like a problem that I should bring to my local garage or will I spend a fortune chasing a red herring without any further signs and symptoms to tell the mechanic? I don't want to waste money if it's (somewhat) normal behaviour but I would like to get on top of it early if it is going to cause further problems down the line. Had a disaster of a time with my girlfriends previous car and don't want a repeat of that again!

Thanks in advance for any info or advice

[Shambles]

Hi hyuni30 

What's the service history like?

[hyuni30]

Thank you! The car has a full service history, last serviced when I bought the car 6 months ago. Oil checked regularly and no signs of a leak as of last check (10 days ago). I did have an issue with idle stability on cold starts when I bought the car but that was seemingly sorted by a software update. Three out of four of the glow plugs were also faulty when I bought the car and were replaced by Hyundai under warranty. I got the car from a main dealership. The idle instability is now appearing regardless of whether the car is cold or warm and is not limited only to cold starts. Hope that helps!

[Paolo39]

Hi,
There could be four things to check:

1 - fuel itself (fuel bug, etc.)
2 - fuel sender and fuel filter
3 - injectors partialy blocked and not delivering right amount of fuel
4 - compresability problem (not likely)

[hyuni30]

Hi,
There could be four things to check:

1 - fuel itself (fuel bug, etc.)
2 - fuel sender and fuel filter
3 - injectors partialy blocked and not delivering right amount of fuel
4 - compresability problem (not likely)

Thanks for this @Paolo39 .

So would you advise taking the car in for a look?

[eye30]

Does the car get driven short or longer drives usually?

If mixture how is the short/longer drives in time/distance and how often longer?

[Paolo39]

Hi,
I almost forgot about MAF sensor. Could be dirty and not giving correct values. If the car is on warranty, then check with Hyundai. If not, I would check all fuel pressures, MAF values, etc. by using ODB scanner with log/record function.

[nzenigma]

From your own assessment, most of the proposed remedies may be out of your reach.
Therefore, this could get expensive, especially at a dealership.

However, bug in fuel is easy, take sample in clear class from pipe above fuel filter. Fuel should be crystal clear.

Do you have DPF on your car? If so, go for a high speed flog down the highway . If no DPF, do it anyway, diesels love it.

MAF cleaner is easy enough to use.
EGR cleaner bit more complicated but an easy DIY.

[hyuni30]

Does the car get driven short or longer drives usually?

If mixture how is the short/longer drives in time/distance and how often longer?

To work and back every day, typically 35 minutes .. 10 minutes slow (out of town), 15 minutes fast (dual carriageway) and then another 10 minutes slow (into town) and then the same back.

Occasionally I use the car for shorter journeys, ie. to town or the gym etc, maybe twice a week

Hi,
I almost forgot about MAF sensor. Could be dirty and not giving correct values. If the car is on warranty, then check with Hyundai. If not, I would check all fuel pressures, MAF values, etc. by using ODB scanner with log/record function.

My friend has one of those, used it on my old Mini all the time .. i'll see what he can do. Thanks

From your own assessment, most of the proposed remedies may be out of your reach.
Therefore, this could get expensive, especially at a dealership.

However, bug in fuel is easy, take sample in clear class from pipe above fuel filter. Fuel should be crystal clear.

Do you have DPF on your car? If so, go for a high speed flog down the highway . If no DPF, do it anyway, diesels love it.

MAF cleaner is easy enough to use.
EGR cleaner bit more complicated but an easy DIY.

Thanks for the tips. By 'flog' do you propose just driving at higher speeds e.g. 70-80mph as normal or is it more effective to leave the car in a lower gear?

I don't suppose there is much chance that this will improve once the supermarket fuel is flushed? I don't want to risk compromising the car but have had a lot experience chasing down a rough idle that ended up costing a lot of money and eventually a replacement car (for my girlfriend)

[nzenigma]

Happy to save your money, but dont have a crystal ball.

I mean go for at least a 30 min trip at speed limit.


you didnt answer question re DPF ?????

fuel is an easy check, did you do that?

There is an additive for the bug, add double shot to tank per instructions, but only kills it does not clean the tank or intake screen

[hyuni30]

Happy to say your money, but dont have a crystal ball.

I mean go for at least a 30 min trip at speed limit.


you didnt answer question re DPF ?????

fuel is an easy check, did you do that?

There is an additive for the bug, add double shot to tank per instructions, but only kills it does not clean the tank or intake screen

Fair enough.

Sorry, yes the car does have a DPF but I haven't had any warning lights to suggest that it is blocked.

I haven't checked the fuel yet but will do that this weekend. Might sling some additive in anyway as a precaution.

Drove home fine last night and same again to work this morning, plenty of stops in traffic etc. No symptoms when moving. Would a dirty IAC, TB or MAF cause symptoms every time or can it be intermittent? typically when the unstable idle does show up it will happen almost every time I stop on that journey but then it always seems to disappear the next time I start the car and drive.

[nzenigma]

I was thinking about DPF regen. We arent burdened with them here on our FD and GD models. So Im relaying complaints from Euro owners that they get similar symptoms.

Failing sensors can give intermittent or perpetual rough drive/idle. Sorry. Also a sleeper is the CKS!!!

You may need to get a scanner, hopefully you will have codes, or live data could tell us more.

[hyuni30]

I was thinking about DPF regen. We arent burdened with them here on our FD and GD models. So Im relaying complaints from Euro owners that they get similar symptoms.

Failing sensors can give intermittent or perpetual rough drive/idle. Sorry. Also a sleeper is the CKS!!!

You may need to get a scanner, hopefully you will have codes, or live data could tell us more.

How long does it take to regenerate (approximately)?

Crankshaft sensor? uh oh.

I've got a basic OBD scanner so i'll stick it on tonight and see if any codes pop up.

If on idle & only slightly, i would personally start out with checking the EGR-valve.

If you have the OBD as bluettooth & an android-unit, you could use the app "Torque" to check for EGR-error, reading out the commanded value vs. the calculated from MAF-sensor. Very easy once you set it up with measurement as histogram.

[nzenigma]

   EGR has been mentioned and is my main concern .I was going add that finding a code would be great, but I doubt that any exist, given the intermittent nature of the idle.
However, even basic scanners show live data which will be more helpful.
Fuel Bank Trim % will be of interest.
 

[hyuni30]

Quick update .. I've been back on BP diesel for the past month, they haven't had the ultimate diesel the last few times i've filled up so i've had to make do with their regular. No symptoms now for almost a month though. Touch wood. Hard to believe that supermarket fuel can make such a difference.

[Dazzler]

Quick update .. I've been back on BP diesel for the past month, they haven't had the ultimate diesel the last few times i've filled up so i've had to make do with their regular. No symptoms now for almost a month though. Touch wood. Hard to believe that supermarket fuel can make such a difference.

That's good to hear.  Thanks for the update.