Vacuum cap keeps getting blown off!
 

Hey guys. I don't have a picture and the FSM kinda skims over the area I'm talking about.

It's this little tube that comes off of the bottom of the bac on my 89 turbo. I put a cap on it because it makes a loud hissing noise. It's vacuum on idle but when I drive the car it shoots the cap off! I have to put the cap on everytime I stop the car. If I don't the car idles at like 500 and dies.

I'll get pics tomorrow, any ideas?

Put a clamp on it then.

Clamp it or put a bead of RTV around the rubber nipple next time.

I was going to clamp it. Does anybody know what it used to go to though?

It kindof sounds like the part that goes to the boost pressure sensor but thats just a thrown out guess, since there is no pic yet.

If it has anything to do with the BAC valve, the stock ECU needs it to idle the engine properly.

Why are you trying to plug it?


-Ted

The Bac doesn't have a nipple on it though. Or at least the s4 ones i've seen. Just the two coolant passages.

It's dark here.. let me paintshop..


http://i9.photobucket.com/albums/a72...nEaten/cap.jpg

Sorry I can't go outside and take a pic it's 1 am. It's right under the bac valve.
RETed I've read a lot of your articles on removing the bac. You seem very adamant in people keeping them on. Quote Aaron "c. Slightly cleaner engine bay... Yay!" just doesn't seem worth the loss in driveabilty.

That being said, capping off WHATEVER this is increases driveabilty. If I could find out what it originally went to (since the asshat before me obviously removed it) I would put it back where it belongs.

For the record: ac, air pump, and ps all deleted :(

I just realized how terribly drawn that is. I'm glad I put "BAC" on it or it would look like a rude sex toy.

It's for idle control.
That 5/8" fitting you're trying to cap is the inlet / source for the air going into the engine.
It's normally runs to short hose that goes into the pipe splitter sitting on top of the turbo.
Are you running an aftermarket BOV or an FMIC?
If so, that would explain it.


-Ted

I am running both, but I plan on going back to the TMIC within the week. It goes onto the piece of ic piping right after the turbo? The one that looks like a tree that branches onto the stock bov hose?

So what should I do with this while I'm still FMIC? Cap and clamp?