Another V10 FSI carbon clean

[Conquistador]

A long post, I know, but there is a question at the end so please bear with me


I've half succumbed and half been forced to do the full decoking and intake manifold flap removal work on my S8 over the last couple of weeks.

I took my car to an excellent local specialist I always use, to investigate and fix a small oil leak. Turns out it was a small rubber seal just the diameter of a 2p coin on top of the engine's 'V' right at the back under the filter. Job done.

When the manifold was removed, a worrying sight greeted them and and they stopped work and called me over to have a look (I work literally across the road so they were happy for me to walk over any time). A horseshoe shaped piece of place plastic, which was part of the intake flaps within the manifold, was balancing on on the flap of one of the intake ports. It was a bit baked on to the port which suggests it hadn't just dropped out when they lifted the manifold off. It would surely be game over if that had fed itself to the engine's internals.

They got an endoscope into the manifold which confirmed the inevitable. The manifold flaps were $hagged and it was carbon galore in there. I then found myself in a tricky situation whereby places such as VRS in Northampton and AMD Essex will only undertake the whole work (manifold flaps, engine decoke and remap) and weren't interested in doing half jobs, which I suppose is fair enough. I was uncomfortable having the manifold put back on the car to start the engine and drive it somewhere to get the full work done, so took the manifold away and desperately tried to find a place to gut the manifold of its plastic flaps.

I read of a place on Pistonheads recommended by a few S6 V10 owners. 'JR Tuning' near Maidstone in Kent. From everything I read, they seem to know what they are doing and have endless S6s, RS6s, RS4s and a few S8s in for this exact work and more. I took the manifold down to them, collected it the next day (for an excellent price) and presented it back to my local garage to fix back on to the S8. They are all ex-Audi and VW master techs so aren't completely au fait with gutting a manifold as it's not exactly work that a main dealer will get involved with, but they all gathered round to gaze at the wonderful design of the gutted internals of the manifold . Btw, Audi would be happy to relieve you of £3,100 for a new manifold and associated parts.

Anyway, JR Tuning gutted the manifold and removed the broken plastic flaps as well as the big metal chamber which houses them (the thing that looks like a foundations piling drill) so the manifold is now a hollow shell. The two actuators / potentionmeters on the front of the manifold are now obviously redundant and serve no purpose and have been unplugged and removed. They had thin metal arms connected to them which controlled the [now removed] intake flaps so my question is, should I plug them back in? I'm aware that I'll get the engine management light come on because of the manifold work but should I leave the actuators plugged in and just remove the control arms or leave it unplugged with an open connection?

I've had the car some time now and got away with only routine maintenance work so I've taken this opportunity to do the spark plugs/packs, air filters, rocker cover gaskets, replace the big air breather pipe (which can cause rough idle on a cold start if ruptured) and any other gaskets or pipes they come across plus the front belt. When the car is back together I will be taking it straight to AMD Essex who are happy to decoke the engine then custom remap the car.

FSI = F*cking Stupid Idea