This is more curiosity than anything. I noticed that the C valve on this solenoid is vented, but through a hose that appears to have a restrictor at the end (the little hose that snaps on top of the hard lines). What's the purpose of the restrictor?

 

Its not a restrictor. It's a filter

 

There's a filter on the end, but the metal connector between the hose and filter seems to have a very small pinhole opening. It looks intentional, otherwise I think they would have put the filter directly onto the C valve like the other solenoids.

Here's a snapshot:

 

Never seen that before. Definitely a restrictor yes. No idea what purpose it would serve

 

I guess if/when the solenoid is deactivated then the release of vacuum would be slowed down by the restrictor. Maybe this creates a "soft landing" for the butterflies.

 

Yep, my guess would be to slow the closure so it's smoother. Could also be to slow the release so it prevents noise - may get a tiny "whoosh" noise or something otherwise.

Dale

 

I would suspect it's not stock.

Unless I'm totally unobservant, can't say I've ever seen one rigged up like that on the multiple rat nests here.......If you're saying it's between the filter basket and the solenoid in post 3. One-way is in place on the post throttle line?

 

Yeah, the restrictor sits between the filter and the C valve, just a brass connector with one end tightened up. If it wasn't original then I would have expected the filter to be stuck directly on the C valve like the other solenoids. The fact that the filter is connected via a hose, and also that the hard lines come with a clip to hold that hose seems to indicate that it was intentional design.

(Yes, my car has the check valve above the switch. I'm guessing the check valve keeps vacuum up, and thus the butterflies open, even when you let up on the gas)

When you think about it, this solenoid should only flip once per engine session, when the engine gets warm, and then flip once after you turns the car off. I doubt the engine ever cools down enough mid-session to release the solenoid. Dale's whooshing theory makes sense. The engineers probably didn't want the car making a weird little popping noise when you turn the car off. That could be alarming to a new owner. I guess I now have a research project once I get things reassembled.

This is purely academic, but there are very few mysteries left.