97 GLT EGR Vacuum Switch Issue?

andyleonard · Post by **andyleonard** » 10 Dec 2021, 13:42

I'm working with the small black 3 outlet-plus-12v vacuum solenoid that's on top of the radiator under the black flap. It has constant vacuum through a one-way valve from the manifold and it has a 12V CLICK when the ignition is on. When I test the 3 (?) why 3? outlets I get a hard vacuum on the manifold side that releases when 12V is applied, as expected. BUT, when the 12V goes on and the solenoid opens - applying vacuum around the engine to the control can atop the ERG on the turbo - I ALSO get flow from the 3rd brass snout on the non-business end, which had/has a hard plastic not-quite-a vacuum-plug on it.

Isn't this a vacuum leak to atmosphere and possibly a cause of lean idle? Is the hard plug normal, some kind of breather and supposed to be there? Or is the part faulty and leaking internally?

Help.

Post by **erikv11** » 10 Dec 2021, 14:50

Just an FYI in case it is useful and as I don't have the attention span right now to think through your post: there is no EGR on your car, that part you are talking about is the SAS solenoid and the metal can thing on the exhaust is the SAS valve.

Oh more to consider: SAS only works at startup and occasionally at stop lights. SAS valves on these cars are notorious for failing. If it's never been replaced, it's probably broken (open), and the pump under the battery may be full of water too.

andyleonard · Post by **andyleonard** » 10 Dec 2021, 16:27

OK, not EGR, SAS. What I'm asking doesn't really include the can on the turbo. I'm asking about the vacuum solenoid on top of the radiator because I believe it's leaking air into the manifold when it's open, whether it be at startup or at a stoplight.

I'm asking if the vacuum solenoid should allow air in it's vent when it opens and is allowed to pull on the can.

Post by **abscate** » 10 Dec 2021, 17:37

It should not. If there is an open port there it needs a cap off.

The solenoid function is to vacuum actuate the Supplemental Air System ( SAS) valve that floats above the exhaustvmanifold like a UFOr

It’s a simple one way through valve.

Post by **jreed** » 11 Dec 2021, 06:06

I've also got a 97 GLT and if it would be of use to you, I could take a picture of the lines and plugs on my solenoid and post it so you can compare.

andyleonard · Post by **andyleonard** » 11 Dec 2021, 10:48

A pic would be great. I plugged the 3rd snout and didn't get an appreciable increase in vacuum on the gauge so...
Mine looks like this: And the solo brass snout passed vacuum when the plastic one was opened. It has a hard plastic cap on it that moved a little, like it wasn't designed to actually seal the port, just keep junk out. ???

Post by **scot850** » 11 Dec 2021, 12:29

Is that not one of the PCV system valves? They look similar to that and on a 98 V70 it is near the back of the radiator.

Neil.

andyleonard · Post by **andyleonard** » 11 Dec 2021, 13:26

Dunno what I've got in several areas here. My son brought home a nice 105K miles 97 GLT that's been worked on by a shop so bad they couldn't get it to run. There's a parts salad to deal with and I'm not a Volvo guy. Making good progress but...PO455. EVAP next and then I think we're done.

Post by **jreed** » 11 Dec 2021, 16:01

That image looks like a Pierburg turbo control valve / boost control valve / solenoid I got from a '98 in the junkyard a couple years ago. If you search for TCV or BCS on this site you can find more info about it and how to hook it up to the wastegate and other connections.

Post by **rguzz** » 14 Dec 2021, 19:39

I have no idea if this helps, or not.