No turning back now

[Delboy]

Originally Posted by Turbo Tony

Thanks for the pics, Del. Wow, that's a lot of gunk for an engine that's reputed not to be too bad with carbon deposits.

I think you've made up my mind for me, I'll definitely get mine done.

How does the car feel now that it's done? Can you tell a difference?

No it doesn't feel any different sadly.

But i feel happier in the knowledge that its clean inside for now.

Be interesting to see if the MPG's improve.

When i was at Clive's place I asked how much they charged for a carbon clean and the answer was £120 per cylinder including Vat sounds like a lot but its a lot of work TBH

[Delboy]

Not happy now, been out to the car this morning to clear down codes etc after all the work, fire it up and could feel a lumyness to it.

logging shows up an intermittent misfire on cyl 6

Guess i'll have to do more work on her.

Just dont know where to start looking TBH theres not much not been looked over the last few months.

[Turbo Tony]

Hopefully, it's something simple like a spark plug or coil pack not quite seated correctly.

[Delboy]

Originally Posted by Turbo Tony

Hopefully, it's something simple like a spark plug or coil pack not quite seated correctly.

Hope so too, I will find out in due course.

[ainarssems]

There was a fair bit of carbon but I would not call it bad at all, I would expect power loss was not more than 10%. Some TDI's have a lot more buildup including 2.5 that I have on our A6. I was considering doing our A6 but took the pipes off and they were slightly better than yours so I decided it did not need doing it. As far as the oil in the intake goes i would not try to reduce it because oil contains cleaning additives and solvents, and on direct injection engine you do not have any fuel in intake so oil needs to do all the cleaning. Obviously if you do not have EGR and no oil than there will be nothing to form carbon buildup. But there is always going to be some oil that will burn on if in small quantities but if you have relatively lot of oil going in there it will clean it as well. I think that might be the reason why our 2.5TDI in A6 have a lot less carbon buildup than others I have seen online even if it has done nearly 200k miles now. It has old style oil separator and while many recommend to replace it with newer style I have left the old one.
On another note on D2 40V engines there is PCV valve/oil separator to reduce amount of oil entering intake and they suffer from seized intake manifold flaps and broken arms as a result of that, on 32V there is nothing there so you have plenty of oil going in intake and I have not heard of any flaps seizing on 32V engines.
Either way you want some cleaning agent going through the intake be it fuel or oil and some on new VW engines have dual injection indirect+direct so you get clean engine and great power/emissions/fuel economy. I could be an idea to add small fuel injector in the intake.
Sorry to hear about misfire after the work done, just an idea but I had injectors cleaned while my engine was in bits and one failed pretty much straight after it. I was getting intermittent both misfire and electrical open circuit codes for one cylinder. I think ultrasonic cleaning have shaked loose solder joint inside one of injectors.

Couple of pictures of bad carbon buildup, not mine, sourced from the web:

[Mechcanico Lee]

Good post Del , thanks for taking the time to do it , you know sometimes on diesels when I have removed injectors for compression blow by on the copper washer at the bottom a few times the injectors have failed after .....I think just disturbing them upsets em and sees them off .... it could be something else but just a thought .

Wouldn't you think you would feel some performance gain with it being clean , I've seen diesel combo vans with ports that are an inch and a half wide Black Death fouled up to the thickness of a pen ..... and you know ....they still drive pretty well , suppose with a turbo behind it pushing it in it can still get a fair amount of air .

Let us know how you get on with the miss fire 👍

[Delboy]

The thing is Lee that the new injector was installed in cylinder six and was tested good.

I'd appreciate any pointers you can think of as my sanity is wearing thin.

[Mechcanico Lee]

Mmmmm .... any possibibility the pins have opened up a little on the connector plug that goes on that number 6 injector .

How does the injector seal at the bottom ...is it on a copper washer ? Any chance you have 'doubled up ' and left the old washer in the head ?

Direct injection injectors the tip protrusion into the chamber is quite important for the 'fogging ' spray patten .

I found this out the hard way ....doh !! .......few years back I fitted a couple of injectors to a Cdi 220 Merc , I did spot that the copper sealing washers were a little thicker than the old ones ( maybe 1mm thicker ) just didn't think it would make much difference ....you know ...as long as the fuel gets in there sort of thinking ....the car belched black smoke like it was a pile of tyres on fire and reported cylinder miss fires .......loads of further tests and checks later wondering what's going on I fitted the correct thickness copper washers and job sorted , running a treat no black smoke ...doh !! Always learning !!

Did you have to remove coil packs or plugs ? Something disturbed there ?

Can you feel it missing like a dropped cylinder , worth putting a vac guage on the manifold to see if any pulsing .....thinking possibly the clean on the valves have dried the guide and valve stem out and valve sticking in guide somewhat , bit of a long shot but I'm just throwing ideas in .

[Delboy]

Mmmmm .... any possibibility the pins have opened up a little on the connector plug that goes on that number 6 injector .
Could easily be a possibility

How does the injector seal at the bottom ...is it on a copper washer ? Any chance you have 'doubled up ' and left the old washer in the head ? These injectors are sealed with a teflon ring and therefore should sit and I fully believe it is sitting at the correct height.

Did you have to remove coil packs or plugs ? Something disturbed there ?
Yes they have been off a few times in my ownership, as this cylinder 6 has had intermittent misfires for a while now.

Can you feel it missing like a dropped cylinder , worth putting a vac gauge on the manifold to see if any pulsing .....thinking possibly the clean on the valves have dried the guide and valve stem out and valve sticking in guide somewhat , bit of a long shot but I'm just throwing ideas in.
Certainly shouldn't rule this out but the misfires are so infrequent that I would think it's not that.

A vacuum gauge is one thing I don't have at my disposal at the moment.

I do have a compression tester and I done a compression test on all the cylinders prior to the carbon clean and they all came back good, despite that I still had the odd misfire.

I also put a full set of new plugs in her, and moved coils around to see if the problem moved, which it doesn't.

I was messing around with VCDS yesterday and cleared out all the fault codes from the car after all the work i had done and I thought it felt better than after a run the other night.

So i'm wondering if there is some other issues with something like 02 sensors, or something else that once the trims start to take effect the misfire becomes more prominent???

For now though I think I ought to check out the coil pack wiring as you mentioned because thats been disturbed the most lately.

I'll record a video of the misfire counters and upload here so you can see what I'm taking about.

Thanks

[notorious]

North Korea Missile Technologies

Love that robe !