How much should a decoke and injector clean cost ? (VW GTI)

[anonymous-user]

[redacted]

[john banks]

Curious how many miles it has, how old, and what symptoms you feel?

Ours is 8 years old and 62000 miles. It is standard, seems to pull OK for what it is. I've not taken the fuel pump off to look at the cam follower either yet.

[t400ble]

Decoke? Have we gone back to 1970?

[ManOpener]

Average quotes seem to be in the range of £400-450. Not cheap by any stretch of the imagination. To my knowledge you can't use any of the other engine cleaning services because they all use the fuel supply system and therefore don't wash over the valves.

What makes you think it needs doing? There's a lot of scaremongering about it on the internet; my understanding is that it's predominantly an issue caused by a combination of poor quality oil and lots of short journeys. The crap design of the OEM PCV, causing it to deposit oil vapour over everything, doesn't exactly help either. Most of the symptoms of head coking can be caused by other, much less invasive and much easier to remedy issues.

[garycat]

Have you considered using the Terraclean system that Edd China advertises

http://www.terraclean.co.uk/

Should be about £110 cost.

[ManOpener]

Just EML or EPC? Limp-home mode or none? Only under light load, or loads light or above? Misfire? Wandering idle? Hesitancy on cold start?

I'd personally have someone run a diagnostic on it with a VAGCOM before shelling out £x00 for a decoke it may not actually need.

Could be coilpacks (again), could be PCV (again) could be cam lobe, intake manifold tumbler stuck or motor seized, boost leak or dead diverter valve, throttle position sensor, MAF, HPFP itself or all manner of other things.

Coking on valves tends to cause a rough/wandering idle and difficulty starting as well as EML/limp-home AFAIK.


Fairly certain Terraclean doesn't work on FSI engines, as the detergent is introduced via the fuel system it won't ever wash over the valves (the main point of coking on the TFSI) like it would an indirect injection engine.

Edited by ManOpener on Thursday 22 May 13:39

[ManOpener]

If they're doing a proper laptop diagnostic they should be able to actually give you the ECU error code. I've not heard of occasions where the EML comes on without some kind of actual error code being logged.

My concern would be that, as the car isn't showing any other signs of cylinder head/valve coking, it would just be money down the pan. Looking back through PH I can see you were reporting this issue years (!) ago. Has it got worse, or is it largely as it was back in 2012? It certainly sounds like something sensor, electronics or ECU related to me rather than a physical manifestation of anything.

[Monty Python]

Try a few tanks of Premium Unleaded?

[rigga]

Monty Python said:

Try a few tanks of Premium Unleaded?

Again no good as its a direct injection engine, fuel of whatever quality does not pass over the inlet valves to wash off any deposits from the recurculated breather system

What you want is what's now being offered to BMW and mini owner's, walnut shell blasting.
Clearing Carbon Buildup in an R56 MINI Cooper: http://youtu.be/R-HlWELr4Zk
Cost varies from independent specialists at around £180 to main dealers £300 or so

[Pickled Piper]

Surely just needs a regular Italian tune up?

Try some STP or Similar injector cleaner. I know it will not decoke but will get injectors clean. Use it neat, wait until the tank is near empty and then use the whole bottle. Then give it a good spanking (Car not Wife).

[aka_kerrly]

This is odd, no fault code but engine management light on, that's quite rare. Has the throttle body been played with at all? there is a reset procedure to ensure that it is correctly aligned and opens fully when required. If it has become out of sync then especially at very light throttle this could be what is "upsetting" the ECU.

Spending 500+ as essentially you would be performing a full head gasket kit replacement plus having the head rebuilt/cleaned on a 46K mile old engine could be classed as overkill when it's not 100% confirmed that there are any issues with the head. Besides the head could be inspected internally using a tiny camera rather then pulling it all apart.

[va1o]

I have fun and games with mine with the odd unexplained engine fault code and AC not wanting to work, so that's fairly standard with these I'd say!

Have you changed the diverter valve? It's probably the most common part to fail on these and causes the turbo to leak boost resulting in reduced performance and poor mpg. Cheap fix as the part is only 40 and half an hour tops to fit it.

Oh and check what software ECU is running as I was told by an Audi mechanic the other day that early versions can cause the EML to incorrectly come on. Update if it's not on the newest.

Edited by va1o on Friday 23 May 19:04

[Wacky Racer]

Pickled Piper said:

Surely just needs a regular Italian tune up?

Try some STP or Similar injector cleaner. I know it will not decoke but will get injectors clean. Use it neat, wait until the tank is near empty and then use the whole bottle. Then give it a good spanking (Car not Wife).

That made me chuckle.....