Cylinder Head / Vacuum

[haddock_n_chips]

Hey everyone,

Anyone know what this hose is / does?

Any idea why if i clamp it the revs/idle drops significantly?

The original hose was cracked and damaged, so I replaced it with a new piece of hose (just some bog standard hose i had spare) and it seems to have helped lower the idle slightly but not completely.

It goes into a T-Piece (this is fitted into the rubber boot part on the throttle body), then runs to the back of the cylinder head. The other part of the t-piece goes to the lower connection on the idle valve attached just near the R/H suspension turret

[Nate]

Hard to see in the pic. Is it the breather pipe?

[mark1gls]

The pipe is for the air shroud injector, not really sure what it does but I think it add air to the injectors?
I only know about it as when I changed my injectors I was asked what sort of injectos I had and when I did not know they asked if there was a rubber pipe between cylinders 3 and 4 and said I had air shroud injectors.

[haddock_n_chips]

Something to do with the airshroud injectors sounds about right

Its a rubber pipe attached to a small metal pipe sticking out of back of the head between cylinders 3 & 4

We just replaced all the injector shrouds as one was broken.

Just wondered what it is/does as had small issue getting a decent low idle. The idle screw is all the way in there is no more adjustment.

WiLL.

[litlekris]

If the 7mm idle at the back of inlet is fully in then the engine is getting air in from a leak somewhere else. When you've clamped that pipe it shows that the source of the leak is narrowed down to that area or inline to it. Best to get easy start and spray it about and find out when it picks up a bit, fix leak.. The idle will go lower or cut out, then you can reopen the screw at the back of inlet.. (hopefully)

[mark1gls]

There should be a rubber O ring on the idle screw, what happens is it goes hard with old age and cracks and either falls out or splits and let's air in. If you remove the idle screw you will see it, any old o ring which fits will work.
Looks like this
http://www.ebay.com/itm/Vw-Rabbit-Mk1-G ... 0364883704

[haddock_n_chips]

Thanks for the replies

Going to have a play this weekend,

Need to sort some minor stereo wiring issues too

Will report back once i have had a play

WiLL....