Misfire at idle and load, engine hesitating, damnit!

[MrFwibble]

Having some trouble with the ol' TFSI. Intermittent, but seems to be happening more often as time goes by.

On idle, cyl 4 will show some misfires, more after a long drive. Maybe 10 every 30 seconds or so.

Driving around town or low throttle seems to be OK but as soon as you go medium to high throttle it will hesitate then go then back to hesitate again. No strange noises and no warning lights on the dash. VCDS scan shows no error codes.

I've done some logging with VCDS and things like Boost Requested and Boost Actual match very well, so I don't think the DV has gone.

3 of the coil packs were replaced last year at SEAT, but I got another from Dave @ SERE (Thanks mate!) and put it on cyl4 with no difference. (Part codes were the same on the old and new).

Spark plugs are NGK, replaced about 18 months ago and look fine.
http://1drv.ms/1o151rd
I have ordered some new ones just in case its faulty in another way.

Lambda figures look off to me but im not sure, can anyone confirm?

13:21:16 Group 032: Lambda Regulation
  0.4 %  Lambda (Idle) Self-Adaptation
  2.3 %  Lambda (Partial) Self-Adaptation     

13:21:16 Group 033: Lambda Regulation
  -4.7 %  Bank 1 Lambda Control
  1.48 V  Bank 1 Voltage of Oxygen Sensors
              
13:21:16 Group 016: Misfire Recognition
  10  Cylinder 4 
              
  Enabled  Malfunction Recognition

I have added my VCDS log http://1drv.ms/1o151rd - Marker 6 is where I did a 3rd gear WOT run until I ran out of road Before marker 7 & 8 where when I noticed the hesitation.

I did a reset in VCDS so these values are after about a 20 minute drive.

I had a good read of this thread http://www.seatcupra.net/forums/showthread.php?t=372678

Should I suspect a faulty injector in cyl 4?

Cheers
Dave

 

[Joshkcupra]

It could be a faulty injector mate, or it could be a clogged up valve, the direct injection engines are notoriously bad for the intake valves clogging up with carbon deposits.

 

[MrFwibble]

Yeah I'm hoping its not that, as that sounds like a real PITA to fix :/

 

[mike0105]

If it is a carbon clogged intake, then it might be worth having it terracleaned with their new direct injection intake clean. Am thinking of doing it myself soon but can't really justify the cost right now. Haven't heard whether it is any good/ effective, but if it does the job it is much easier than manually cleaning the intake valves!

This is the new system they use http://terraclean.net/product.php?id=2.

 

[MrFwibble]

Wonder if that actually works, there is a local terraclean agent near work, might pop along.

So far im thinking I'll ask my mechanic to replace injector on cyl4 and while the manifold is off just clean the intake as well.

 

[mike0105]

That would be the belt and braces approach, would be good to know if the terraclean works though.

 

[MrFwibble]

Yeah me too. Will explore all options

Just realised that the Lambda values in my logs are incorrect, I logged the wrong block I think.

Is there any benefit in fitting a catch-can?

 

[MrFwibble]

Re catch-can, done some research and it doesn't appear to stop the carbon build up.

After speaking to the local Terraclean guy I am going to give it a try, £108 for a normal Terraclean and also the Direct Injection specific clean.

Going in with low expectations, will see what happens!

 

[Joshkcupra]

The catch can mainly stops the oil/crap building up in the intercooler.
Let us know how you get on with the terraclean I've heard mixed reports.

 

[MrFwibble]

Will report back after its done on Thursday

 

[mike0105]

Looking forward to the outcome. If it works out I'll be booking mine on. 53k must have cause major carbon deposits.

 

[MrFwibble]

Terraclean done, exhaust tips are now filthy!

Car does seem to be a bit more responsive on the throttle, not sure on mpg will have to wait a week to find out.

Didn't fix my issue however! Boo. Going to put VCDS back on this weekend and do some more logging and see if Cyl4 is still registering a misfire.
Issue seems to be more prominent when accelerating from low revs (2000-2500) and its like the car just loses power.

Hope its not the turbo!

 

[mike0105]

Sorry to hear it didn't fix the issue.

What do you reckon to the intake clean then? Worth it on first impressions, I know you say abit more responsive but could that be placebo or is it a definite?

 

[MrFwibble]

Being honest, it could be a placebo! Didn't push it too hard on the way home as it was pissing it down (typical Scotland).

Will see if the weather improves tomorrow and give it the old Italian tune-up and report back

 

[MrFwibble]

Went for another vcds logging run but typically it never did it (story of my life!).

However it did go like **** off the proverbial shovel Not sure if that is down to the Terraclean or not, still undecided if that has had any effect.

Did another log, this time with correct lambda values
http://1drv.ms/1sfhqDt (file called LOG-7-NOV).

Markers 2 & 4 for 3rd gear WOT runs until I ran out of road.

Can anyone see anything unusual, everything seemed OK.

At line 1723 I was back home and idling, look at cyl4 just tick up on the misfires. Only that cylinder does it. Grrr.

Going to swap the spark plug from 4 to 1 tomorrow.

 

[MrFwibble]

Terraclean must of done something, spark plugs are filthy covered in carbon ! They were fine last week, lol.

 

[MrFwibble]

Injector replaced, cured the problem. Garage said the intake wasn't that bad but gave it a clean anyway.

 

[mike0105]

Injector replaced, cured the problem. Garage said the intake wasn't that bad but gave it a clean anyway.

When they say wasn't that bad, do you reckon that was because of the terraclean?

 

[MrFwibble]

Yeah I guess it could be, hard to tell.

Seems that driving style may have an impact on the build up. My commute is 32 miles each way, mainly dual A road sitting at 75mph on cruise so it gets nice a warm which might help ?

 

[ramborobert]

i need to get my injector changed too same symptoms as yours except on cylinder 3. I read somewhere that the terraclean didnt really work properly on these engines?