1997 Volvo 850 Vacuum Hose Routing Questions

shaolinpat · Post by **shaolinpat** » 18 Oct 2019, 19:05

Hello,

I've been fixing my vacuum situation on my 1997 850 T-5 (no EGR).

I'm trying to get hoses hooked up correctly, but am having an issue. I've got more hoses to connect than there are connections.

Following this photo

: vacuum-hose-diagram-850.jpg (150.39 KiB) Viewed 4008 times

I have one hose going from the TCV (the part labeled 16 in the diagram) to the turbo wastegate (the yellow hose in the diagram). That seems right.

I have a second hose going from the TCV to the turbo compressor (the green hose in the diagram). That seems right.

I have a third hose going from the TCV to one nipple on the hose to the turbo (the blue hose in the diagram). That seems right.

I have a fourth hose that's supposed to go from the turbo to the front of the intake manifold (the red hose in the diagram). Is that right?

I have a fifth hose that goes from another nipple on the turbo hose (by the PCV) and I don't know where it goes. This is a stumper. There doesn't seem to be anyplace it can go.

I have a sixth hose that goes from under the air box to the intake manifold. That's seems right.

I have a seventh hose that goes from a hose near the fan to the intake manifold. That seems right. (See the attached photo.)

So ... between the fourth and the fifth hoses, it seems like both could go to the intake manifold, but both can't. One suggestion to me has been that the hose by the PVC goes to the TCV, but the third hose is already going there.

Here's a picture with labels showing what the hose routing is at the TCP. Note, the plugged port is just a port that could have a tube to it but has a plug that slides off instead.

Here's a labeled photo from the turbo end of things.

: turbo_hoses_labled.png (1.01 MiB) Viewed 3999 times

I'm pretty stumped. If the hose labeled 2 in the above photo goes to the intake manifold, where does the hose labeled 4 go to? Or should it get plugged like the other one on the turbo hose?

Thanks.

Post by **abscate** » 19 Oct 2019, 08:00

Turbo cars vent the Evap system in two places, one from the intake manifold and the other from the snorkel ( the big fat hose between air cleaner and turbo.

That’s your missing hose.

shaolinpat · Post by **shaolinpat** » 19 Oct 2019, 08:19

@abscate,

I'm sorry, but I still don't understand. I'm still not sure where to plug the other end of the missing hose into.

I've added a couple of labeled photos.

shaolinpat · Post by **shaolinpat** » 19 Oct 2019, 10:39

I see where the EVAP system connects to the intake (see the pic with my fingers in it). But I don't see a second place where the snorkel can connect. On some cars, there's a t-connector after the evap solenoid, but mine doesn't have that.

Here's a pic that jblackburn posted, which I done some labeling on.

: evap_clean.png (544.46 KiB) Viewed 3995 times

So the turbo snorkel doesn't hook in there, where would it hook in?

Post by **abscate** » 19 Oct 2019, 11:53

Do you have a label under the hood showing your vacuum routing? Look near the base on the passenger side

shaolinpat · Post by **shaolinpat** » 19 Oct 2019, 12:03

No diagram. The hood was replaced after an accident. So if it was on the underside of the hood itself, it's long gone.

Post by **xHeart** » 19 Oct 2019, 14:01

Unless someone says otherwise, the vacuum hose #4, connected at the fresh air pipe to turbo, connects to the valve (grey plastic) near the fan in your pix with two fingers, NOT to the copper nipple at IM.

shaolinpat · Post by **shaolinpat** » 19 Oct 2019, 17:43

Maybe. I've just never seen that gray plastic connector go to anything but the intake manifold. I've seen it go there with no t-connector and I've seen it go there with a t-connector. And I've never seen anything else go there.

If I left the hose that hooks into the snorkel unconnected, would smoke testing show me where the other end should connect?

Post by **abscate** » 20 Oct 2019, 06:26

I realized we are missing something else

Your car has vacuumcontrolled fuel pressure regulation, so there is another vacuum line running to the FPR unit,either in the fuel rail or down on the steering rack area

shaolinpat · Post by **shaolinpat** » 20 Oct 2019, 08:32

There are two lines that go into the vacuum tree.

This is the line from the fuel rail.

This is the other line, which comes from along the driver's side of the car. I don't know where the other end goes. I call it the mystery line.

: mystery_line.jpg (210.51 KiB) Viewed 3976 times

The mystery line is in OK shape, so I'm not replacing it. The fuel rail line is being replaced, by some silicone line I have from fcpeuro.com that's a little big, but that's what clamps are for. I've tried to find the hard plastic lines with the rubber boots online, but can't find them.

Still have the one line from the snorkel near the PTC that I don't know what to do with.