Help! S8 Scary Engine Noise...Worried

[HPsauce]

Having had mine off it's held by Clic-R collars/clamps which are best removed/replaced with specialist pliers.

[mark_le_b]

Originally Posted by Goran

I think you're onto something there! perhaps the rubber diaphragm has failed and is vibrating as it lets air out?

Its the black plastic UFO type object at the back of the engine.

Here it is in a picture I borrowed from another forum member's post as it shows the engine bay without covers.

It is easy to remove by jubilee clip or the Audi type clip, but I'm not sure if its safe to run the engine without it or with the rubber hose plugged to test if the noise stops?
Probably ok for a minute or two, as its just a sprung rubber diaphragm to let some crankcase pressure out when it builds up enough to be able to open the diaphragm.

This is how it looks inside:

http://forums.quattroworld.com/a8/threads/8649.phtml

Thank you, I have the plastic covers off the engine, so have seen this
Will run car to see if this is the culprit
Appreciate the ideas

[mark_le_b]

Originally Posted by ainarssems

Hard to say from video but it could be secondary air injection pump if the noise come from air filter box area in which case you could just temporarily disconnect it. If you have VCDS you might be able to test it using output tests or as Audi call them final control diagnosis.

Any idea how to disconnect? Plug seems to be behind air box and I can't get my hand in there! Does air box have to come out first?

[mark_le_b]

Originally Posted by mark_le_b

Any idea how to disconnect? Plug seems to be behind air box and I can't get my hand in there! Does air box have to come out first?

Anybody know?
Thanks

[Goran]

Are you sure you cant reach in behind the airbox and unplug it? I removed my airbox before, I am sure I unplugged it first before taking the airbox out. I just went out to the car, my SAI has been removed but I can easily reach to where the plug used to be.

[mark_le_b]

Originally Posted by Goran

Are you sure you cant reach in behind the airbox and unplug it? I removed my airbox before, I am sure I unplugged it first before taking the airbox out. I just went out to the car, my SAI has been removed but I can easily reach to where the plug used to be.

The air tube that goes from the pump through the air box and out the other side of it is in the way

If the air tube detaches from the back of the air box near the plug then I could reach, but sure how that detaches from the air box, and I dont want to break it!

If you know how tube comes off, then that should give me room to get to the plug

[Goran]

Ah, yes, sorry I forgot about the rubber tube. It is a press fit into the airbox and would have to be taken off the SAI motor unit from inside the airbox. Its really difficult to squeeze through that hole so not worth it if there is a easier way.
I wonder if there is a fuse in the fuse box that only relates to the SAI motor? That would be a much easier way to temporarily disconnect it.

[ainarssems]

There should be a fuse somewhere, not sure where. There is relay for it in electronics box in plenum chamber, fuse might be next to relay.

[mark_le_b]

Originally Posted by ainarssems

There should be a fuse somewhere, not sure where. There is relay for it in electronics box in plenum chamber, fuse might be next to relay.

Guess I need a fuse diagram now

[Goran]

I think I found it, should be fuse S130, a 50A fuse. I cant work out where its supposed to be in the drivers footwell on the side, or in one of the other fuse boxes. Maybe I'm being thick I cant find a fuse diagram in ElsaWin, surely there should be one?
Relay should be no. 4 in the passaenger footwell?