Carbon buildup issues?

[STEVIE-B]

Quick question!

Car has a very slight rough idle. Though revs are staying steady! Spark plugs and a coil have been replaced!

Initially thought it may be the DMF but have been advised that it may be sure to carbon buildup!

Anyone able to offer any advice? Would a walnut blast solve this issue? Anything key to check etc?

The car is a 2.0 tsi!

Thanks in advance!


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[xjay1337]

Most TFSI and TSI have a rough idle.
Can be a million things.
I'd check the PCV system first, and use 99 fuel if you're not already.
Walnut blasting is an option but it's around £300 at a specialist. You don't really lose much power on the turbocharged engines so up to you if it's worth the cost or not.

[STEVIE-B]

Xjay,

Thanks, I have done a little research - I just felt it and naturally started panicking!

I have since realized that most have a rough idle like you said. I am trying to locate a TSI / TFSI locally I can take for a test drive and see how it feels!

I have only had the car a week - I think I will persevere before spending any money, I have a long drive tomorrow and I will see how it is on that and see how it feels then! It is certainly worse in the cold, once it is upto temp it is still there, but i'm being very anal!

Cheers for the advice! I am using 99 fuel, Ill check the PCV this afternoon (hopefully)

[STEVIE-B]

Most TFSI and TSI have a rough idle.
Can be a million things.
I'd check the PCV system first, and use 99 fuel if you're not already.
Walnut blasting is an option but it's around £300 at a specialist. You don't really lose much power on the turbocharged engines so up to you if it's worth the cost or not.

Xjay,

Sorry to be a pain, is there an easy check for the PCV? Or is it just a case of replacing it and seeing if it runs better?

Thanks
steve

[xjay1337]

On the TFSI you unplug the pipe that goes into the PCV and blow into it, if it stops flow and you can't blow then it's fine , but if you can blow without restriction then it's faulty.
I think it's different on the TSI.

Here is a video. https://humblemechanic.com/2015/02/03/h ... ils-video/" onclick="window.open(this.href);return false;

As I said it's pretty typical of TFSI and TSI engines to have a slight uneven idle.

[Paradox1]

You can also take of the oil filler cap. if idle does change then you need a new pcv

[STEVIE-B]

You can also take of the oil filler cap. if idle does change then you need a new pcv

Tried this and no change whatsoever in engine revs etc.

Car is currently in at a garage, fingers crossed! If they cant solve it i'll change the PCV myself this weekend

[Paradox1]

Sorry if the idle doesnt change, then you need a new PCV.

or so ive been told

[STEVIE-B]

Sorry if the idle doesnt change, then you need a new PCV.

or so ive been told

What does yours do when you pull the dipstick? Stall / run rough?

[STEVIE-B]

Ok, checked the PCV by trying to blow through it, and i cant, which makes me think the PCV is operating as it should. I have removed the dipstick / filler cap with ease (believe it should be hard to remove cap if PCV is faulty), and yes, there is a very slight change with them removed.

Still having the issue of a rough idle though, the revs are steady and when the engine is warm it improves slightly. It isn't awful, but the car just feels hesitant when accelerating with low RPM when cold.

Any other ideas would be very welcome!

Understand it is usual for them to have an uneven idle, just feels worse than i would expect, and the hesitation is concerning me a little.

[xjay1337]

No, it's not the difficulty of removing the cap, it's the possibility of the effect on the engine running.

I would not worry, if you are that concerned then take it to a garage who can look at it for you.