Mk3 2.0 GTi strange "chooo" sound from engine bay when accelerating.

[Mr.Tom]

I mentioned it before somewhere, but have better diagnosed it (a little)
Whenever I put the accellerator pedal down while driving, I get a strange sort of soft "chooo" sound from somewhere in the engine bay. Best guess is back against the firewall on the driver side.
It also happens when I turn the engine off.
Almost like saying "tissue" quietly with your teeth together, best way I can think of describing it
Can press the pedal repeatedly and it will do it each time with the engine running.
Any ideas?

MK3 GTI 2.0 late '96

[Paul86S2]

Vacuum leak? Check all the vacuum pipes to make sure they are connected properly and are not split.

Paul

[Len]

Perhaps its a turbo! 

Could be the vac hose to the brake servo?

[Mr.Tom]

Perhaps its a turbo! 

Wish it was
Will take a look at the hoses.
Cheers.

[A7 UFO]

how many people read this

Almost like saying "tissue" quietly with your teeth together

and then sat there quietly doing it?

[Mr.Tom]

Think I found it.
It's a pipe that runs from the right hand end of the throttle body, round the back of it, then behind the brake fluid reservoir.
On 1A.6 of the haynes manual, it runs from point 14 of the bottom picture, round the back of point 4. So a bugger to get to :/
It is split at the end behind the brake fluid reservoir.

What should I be ordering?

[Mr.Tom]

Okay. It was the break servo pipe apparently. Got it out and popped it over to the local garage. They are ordering me one now

[Mr.Tom]

What does it actually do? There is a little valve at the intake end. The engine cuts out of it is disconnected.
But I don't understand what it is for

[Len]

Perhaps its a turbo! 

Could be the vac hose to the brake servo?

Star for Lenny! 

Its a vacuum hose! It assists the brake servo!

[mumbles]

how many people read this

Almost like saying "tissue" quietly with your teeth together

and then sat there quietly doing it?