Can anyone tell me what the vacuum hose that goes into the back of the manifold does? Mine has snapped and i have a new one coming. It looks like it connects to the fuel rail. The haynes manual only mentions that it is a vacuum hose. Might explain why my idle is rough.

Hi

If it goes from manifold to fuel pressure rail, most probably goes to fuel pressure regulator

this alters the fuel pressure dependant on engine load, so no vac, higher fuel pressure, high vac lower fuel pressure

if yours is broken the its most probably over fueling at idle, hence the rough idling

cheers

Joe.

 

 

That clears it all up. The intermittent symptoms that i have had for nearly 2 months is now constant. I was cleaning up the throttle body and maf sensor this morning and for some reason decided to check that particular vacuum line. It had snapped in two places. Im guessing that it was broken long before and was only holding out as it must of been butted together. I have found a brand new one for £23. Expensive part considering how small it is.   

hi

yes they go very brittle and just break

is this the part thats gone https://www.sngbarratt.com/uk/#!/English/FindParts/Families/S-Type and X-Type/12/50/11007/1/10/1

cheers

Joe

The induction valve hose is whats gone. I have made a temporary fitting with a piece of old fuel pipe from a quad bike. Not 100% sealed but hopefully enough to add some pressure to stop the idling to rise too much.

Replaced the hose today. Quick job and big difference. It still revs up a small amount when i press down the clutch. Roughly 400rpm it goes up by. I think that maybe down to the load coming off the engine. But i know my flywheel is starting to deteriorate so wonder if that could cause the problem.