1998 V70 T5 white nylon tube from near MAF ?

[SteveSarre]

Hi all,

I am checking/replacing various vacuum hoses on my 1998 V70 T5.

There is a thin white nylon tube which runs from near the MAF on the fat black air hose that goes to the turbo. It runs down and pushes into a small black hose which disappears below and behind the various vacuum and PCV hoses that run towards the turbo.

If I lift things out of the way, I can see that it connects to a very small diameter metal tube that is strapped to a metal coolant tube down there.

Where does it go next, and what does it do?

Thanks
Steve

[Shinsplintz 101]

https://www.matthewsvolvosite.com/im...se-routing.jpg

It ties into the fuel system, probably to give a base line atmospheric pressure. Dont quote me on that mind!

[SteveSarre]

Hi Shinsplintz

Yes thanks. I have been reading a lot about that and came to the same conclusion.

I found that some S/V70s use an air reference pressure and an external fuel pressure regulator somewhere either near the steering rack and or near the tank.
And some control the fuel pump electronically to regulate the pressure.

Just in case it helps ...
On
https://www.volvopartswebstore.com/s...roduct=1246031

the metal pipe is part number 9445150 and the diagram shows other components

On
https://www.matthewsvolvosite.com/fo...le.php?id=5098
which is for 1998 XC/AWD , it refers to "reference air hose of the fuel pressure regulator".

Also for a general discussion
https://www.matthewsvolvosite.com/fo...ic.php?t=64797

When time allows, I will get underneath and see if I can trace it back somewhere.

And the fuel pressure regulator is not the same as the fuel pressure damper which is on the injector rail....

Thanks
Steve

[PNuT]

Fuel pressure regulator