vacuum pipe left side of fanimold?

**zoomungus** · Thursday 29th January 2009, 17:49

when looking from front there is a vacuum pipe left side of fanimold, op side of inlet to throttle body, what is it?

it was rotten so i removed it and blocked the inlet, it was a pig to get to but i did it.

**BruceT** · Thursday 29th January 2009, 18:13

It goes into the PCV heater nippe (PTC?) its a vacum line that I also have bunged up.

How do you manage to bung it up at the manifold end? There is next to no room lol

**zoomungus** · Thursday 29th January 2009, 18:26

i sprayed it with a tin of boost leak begone.........................then below!

bruce, i practiced swearing for a full 2 weeks before tackling it, i also did it when the engine was hot so i could swear more, that little spring clip took me half an hour to get off!
then i shoved a bung on the inlet tightened it up with a hose clip, job done!

**BruceT** · Thursday 29th January 2009, 18:31

Haha.

What did you bung it up with?

**zoomungus** · Thursday 29th January 2009, 18:42

i had a small bit of fuel pipe, placed a small round bit of rubber in one end, hosed clipped it and then put another hoseclip on and tightened on the inlet, done, getting the old hose off was the crap part!

**t5 stealth** · Thursday 29th January 2009, 19:02

if i was you id reconect it properly as you will upset the running & the general running of the engine....it might seem ok now but with electonics on cars the ecu or brains compensate if they find problems so the car wont run to the best of its potential....volvo made it for a reason...if it was meant to be blocked off they wouldnt of fitted it...lets face it,everything is expensive on these cars,you dont wana make problems lol.

**zoomungus** · Thursday 29th January 2009, 19:24

its kinda strange that they would fit this to the inlet as under boost this would pressurise the pcv system and crankcase.

**t5 stealth** · Thursday 29th January 2009, 22:00

Originally Posted by zoomungus

its kinda strange that they would fit this to the inlet as under boost this would pressurise the pcv system and crankcase.

strange maybe but im sure volvo in there wisdom spent millions in the development of that system for it to do something so im sure they know more about it that the likes of us mortals lol.

**woz** · Thursday 29th January 2009, 22:23

Just today I was looking at a map of the vacuum conecions fo the turbo engine. PM me and let me lknow your email I will send you a copy.

When that hos eperishes, your consumption will drop like a stone and the boost and fuelling will be all over the place. It is better bunged off than that as i stops the air leak. However, it does operate the PCV ehen driven by a signal from the ECU I think so you really need to fix it. It is a piuggy job so I got HLM to do it (and all ??5?? of those little perishers) when I got my RICA done. You need to remove the poser steering pump or pulley or something I think. Its all starifghtforward - just a lot to do.

btw my mpg wemt from 23 to 30 as a result so it pays for itself!!!!
W:>)

**woz** · Thursday 29th January 2009, 22:32

Not as useful as I thought but here is the info. (oops reject as file size too big) They are only 120kb but exceed the limit so PM me and i will email you.

It does not cover ALL the hoses. You prob need to look in the manual for that - or did someone once post up a guide to these???
Cheers
Woz

**zoomungus** · Thursday 29th January 2009, 23:13

Originally Posted by woz

Just today I was looking at a map of the vacuum conecions fo the turbo engine. PM me and let me lknow your email I will send you a copy.

When that hos eperishes, your consumption will drop like a stone and the boost and fuelling will be all over the place. It is better bunged off than that as i stops the air leak. However, it does operate the PCV ehen driven by a signal from the ECU I think so you really need to fix it. It is a piuggy job so I got HLM to do it (and all ??5?? of those little perishers) when I got my RICA done. You need to remove the poser steering pump or pulley or something I think. Its all starifghtforward - just a lot to do.

btw my mpg wemt from 23 to 30 as a result so it pays for itself!!!!
W:>)

i get it now! the pcv has a valve connected to the ecu and opens the pcv at some point but when, at boost or idle?

**PNuT** · Friday 30th January 2009, 04:23

when you get the bits, if you bring your car round i will help you change the pcv system

takes about 90 minutes if you know what you are doing

**BruceT** · Friday 30th January 2009, 07:59

That hose goes to the PCV/PCV heater nipple that comes "on" around 80 degrees of so. It sucks air through a valve and one would assume blows when on boost.

What it will do, if connected will suck measured air, so if its sucking air after the maf then it needs to dumping back into the intake when on boost.

If its NOT sucking, ie bunged, then the MAF knows (I think) the amount of air entering.

But maybe, the MAF takes in air expecting some to be taken in and out by the that vacuum line.

Who knows?

I know Tony has it bunged off with no ill affects.

**zoomungus** · Friday 30th January 2009, 14:55

mine seems ok, in fact its perky!

**dooby** · Friday 30th January 2009, 16:44

Originally Posted by zoomungus

its kinda strange that they would fit this to the inlet as under boost this would pressurise the pcv system and crankcase.

Hiya,

I don't think that's true - I think under boost the air from that pipe actually just comes back in to the turbo inlet hose (and after the MAF, so it's not 'counted' twice). I don't see it pressurising the crankcase the way it's set up.

Cheers, Pete

**dooby** · Friday 30th January 2009, 16:46

Originally Posted by t5 stealth

strange maybe but im sure volvo in there wisdom spent millions in the development of that system for it to do something so im sure they know more about it that the likes of us mortals lol.

They did a very helpful diagram which I think Rufe posted on T5D5 (comes from Vadis originally I guess) so that us mere mortals can understand it :-)

**dooby** · Friday 30th January 2009, 16:47

EDIT hadn't spotted Bruce beat me to it.

Originally Posted by zoomungus

i get it now! the pcv has a valve connected to the ecu and opens the pcv at some point but when, at boost or idle?

As far as I understand it, the valve is temperature controlled - once a temp of 80 degrees is achieved it's open whether at idle or at boost.

HTH, Pete

**zoomungus** · Saturday 31st January 2009, 17:53

well my mpg is better and its running better too!

**mattp** · Friday 27th February 2009, 15:06

sorry to drag this up, but does the pipe in question run from the vac tree along the top of the manifold and into a round thing just underneth the fuel rail? if so i'm about to let it have it, as i'm hoping it could be the cause of my poor boosting and mpg. cheers