Never heard of that before.......

I've just checked youtube - that's the sound!

As the plugs were changed as part of the service, and the noise is around that area i'm thinking you could be on to something here

How easy is it to get to the plugs to check/refit them?

 

Its a little bit of a PIA but its doable by someone that is mechanically inclined.I would bring it back to the shop that did the work since you already paid for it.

 

I'm going to see if I can get them to collect it as I have no spare time other than Sundays

If not, I'll do it myself
I've read through the DIYs - I've replaced an intercooler on my car previously, so it's only a few more bolts than that job

I'm thinking my boost problem isn't (directly) related to the spark plug itself

Could be an incorrectly fitted hose when they were putting everything back together though

 

That was my initial thought- something was causing the low boost.

You said you checked the hoses- did you check the connections to the intercoolers? Anyway, when you check the plugs you'll need to get at all that anyway.

 

I checked all the connections, but the upper intercooler ones are the hardest ones to do with everything still in place, so perhaps they're at fault and I can't see it right now

I'll tear it down on Sunday and see what's what

 

The boost hoses are all easy to check. Just give them a firm tug. If they start coming loose, they are not in. You'll have to tear down to get the upper ones back in though if that is the case. You can use a flashlight to see the upper onese inside the firewall. If there is any type of gap between the intercooler and the metal fitting around the hose, it's not clamped in.

I would just take it back to the shop that did the work since you already paid them to do the work. If they messed something up, they should take care of their mistake for free. If you mess around and don't find the problem, they may not cover the work anymore.

That said, if you are bound and determined to do this yourself, checking the spark plugs is a bit time consuming if you haven't done it before but not overly difficult. The hardest part for me was getting the boost hoses reattached correctly. If you do go to all this trouble yourself, you are going to be kicking yourself for spending 3-4 hours labor cost at the shop for a job you can ended up doing yourself.

Just my $0.02. Hope you get this fixed and are back out on the road soon.

 

The noise gets louder at WOT, and quietens down again when I left off

Still sound like a loose plug?

 

Finally had chance to do some work on the car

I've pulled the coils and plugs

The plugs fitted by the shop are 'Beru Ultra 14FR 6L
DU' .......apparently they're the same ones as RUF use

The plugs were all reasonably tight, they look like they're in nice condition (they should be as they were changed during the service) and they're all gapped at around 0.5mm to 0.55mm (according to the converter that's 0.0197" - 0.0217")

The plugs say 0.8 on them, so I'm hoping I can regap them and stop my 'rattle'

A couple of the plugs have deposits running quite a long way down their thread, the others are completely clean - Is this anything that needs addressing?

Is there anything else I need to check for before I refit them?
I don't want to refit them and find out I need to take the car apart again

From what I've seen so far I'm hoping I can re-gap the plugs and solve my problem

 

Question

My plugs have twin electrodes

The electrodes have a rounded edge to them (allowing them to follow the contour of the spark plugs centre)

If I set the gap so that the feeler gauge fits in between the two the gap is actually slightly larger than 0.8mm (due to the contour)

Should I still gap them like this, OR, should I take the contour into consideration?

Or, should I file the electrodes flat??

 

Did you get the oil changed? Do you still have the boost issue?

 

I haven't changed the oil yet

The car's not been used for a while and I haven't had time to work on it
I went out in it last night, it pulled hard up to 5k but wouldn't rev above that!

I thought that would most likely be the plugs or coils

So, given that occurance last night along with the rattling I thought I'd check the plugs and coils first

I'll tell you about the boost once it's put back together again

 

Ok, car's back together again

In addition to having to re-gap the spark plugs I have found air leaks from both exhaust manifolds where they bolt up to the turbine housing - they're not big leaks, but they're there

I also identified a sticking waste-gate on the left turbo

Car revs up to 5k, but not beyond, and will now boost up to 0.9-1.0bar
(car is stock, not flashed)

 

Just about to look into the leaking headers

Are they held to the turbine housing with studs and bolts, or is there just a bolt going through the header flange which screws into the housing??