2013 Leon Rough Idle

[Liam Reid]

Hi, I'm new to the forum although not to the Seat brand. Had a MK1 Cupra and now a MK3 63-plate FR 1.4 TSI. Had the car from new (leased before purchasing at the end of the contract).

Early last year I had the Leon serviced at a non-Seat garage although the mechanic was ex-Seat. Few months after the service, the car began to idle rough and a start/stop error appeared on the dash at ad-hoc times. I was doing a lot of mileage at the time and the issue became worse to the point where on a 100 mile journey home, the idling became extremely jerky, engine became very noisy, the start/stop error reappeared, alarms popped up on the dash before the car went into limp home mode. I managed to turn the engine off and back on which seemed to clear the issue for 10 minutes before it began again. I got the car to the non-Seat garage to find one of the new Bosch spark plugs had snapped in two. All the plugs were replaced however the idling appears to still be a little rough, even after a good run. I have since changed the HT Leads and spark plugs to NGK's however the idling problem has still not gone away. In the last month the start/stop error has appeared once but no further issues. I've been reluctant to pay Seat £79 to hook the car up to a machine but it is looking like I may have to give in. I've Googled as anyone would however found no reports of a similar issue. Only praise for the EA211 engine. I'm open to any suggestions or has anyone had a similar experience?

 

[ramborobert]

If a small piece of the spark plug entered the cylinder it could have caused some damage. I would get a compression test carried out good luck.

 

[LouG]

No, nothing can get into the cylinder unless the entire insulator inside the threaded portion of the plug fell in. The OP's description said the external part of the plug snapped.

 

[Pondlive]

Hi Liam,

I know this thread is a year old, but did you ever get to the bottom of this rough idle problem?

Cheers, Pondy

 

[Liam Reid]

Hi Pondy,

Unfortunately I never got to the bottom of it. I have since changed the plugs again to another set of NGK and the rough idle has virtually stopped and I've not had any warning lights appear. When having the cambelt changed in November, I asked Seat to investigate but they were unable to find any fault. Interestingly I had a new Skoda Fabia 1.0 TSI courtesy car when my wife car was in for a service a few weeks ago and this was idling rough continually. The car physically shakes when sitting at a junction. The Leon runs perfectly averaging over 50 mpg on 30 minute mixed driving which increases on longer journeys with no rough idle at all. I'm grateful the issue got resolved, but would have liked to know what it was that caused this.

Are you having idling issues or just querying to see if I found the cause?

 

[Boroboy]

This may be partly to do with the fact that the 1.0t engine is a 3 pot engine, they're not as smooth as a 4 cylinder engine, down to design. I found this previously owning a 1.0t Astra, on tickover it could be a bit lumpy at times. Also had oversized engine mounts to help combat the issue. I prefer my current 1.2tsi engine, far smoother than my previous 1.0t. Although I found the 1.0t to be slightly better on fuel.

 

[Liam Reid]

This maybe true Boroboy. Interestingly my wife Skoda is a Karoq with a 1.0 TSI engine and its extremely smooth on tick over. The MPG on the other hand is pretty rubbish. Yes it's a bigger car but hitting low 30's with a DSG box is not even close to the manufacture claims. Glad it was leased. I agree, the 4 cylinder engine should be much smoother and is far more efficient.

 

[Boroboy]

This maybe true Boroboy. Interestingly my wife Skoda is a Karoq with a 1.0 TSI engine and its extremely smooth on tick over. The MPG on the other hand is pretty rubbish. Yes it's a bigger car but hitting low 30's with a DSG box is not even close to the manufacture claims. Glad it was leased. I agree, the 4 cylinder engine should be much smoother and is far more efficient.

The lower power 1.0t engines seem fairly good on fuel, I was averaging 50mpg from my previous Astra 1.0t (105), less from a previous Fiesta 1.0t (125), auto, around 40. My current Leon 1.2t, I'm averaging 44 mpg. So not too bad, but not great. It's dsg too. It'll do 50 on a long run.
Having previously owning a few 1.0t previously, I prefer the 4 cylinder engines. Even though they may be slightly worse on fuel, in some cases.
Other advantages of 1.0t engines, they're lighter and cheaper to make.

 

[Pondlive]

Hi Liam,
Thanks for replying so promptly.

I’ve got a 64 plate 1.4 ACT. Is your car the ACT version? There seems to be a few iterations of the EA211 engine, so it can be a little confusing.
When you say your spark plug broke in two, was it really just broken externally?
The reason I am asking is that my car has had a major breakdown of the Spark Plug, which looks likely to have damaged the engine internally.

Cheers, Pondy

 

[Big Vinny]

I have experienced this with SEAT injection petrol cars before. After about 30k miles the throttle body needs cleaning with degreasant as oily deposits from the bypass recirculation system block the "moon" shaped spaces around the butterfly in the throttle body, and air for idling only is restricted from entering the engine causing oxygen starvation. As soon as you put your foot on the accelerator the butterfly opens and the engine is no longer starved of air and runs normally

I have been thinking about the benefit of catch cans which is a separate issue I know. But a catch can should stop this happening and also stop the same oily bypass deposits gunking up the inlet valve in GDI engines which is another source of rough running.