Can anyone confirm whether or not part #9 in the diagram below is a check valve and should PREVENT air from escaping from the end of part #6 (see red line / arrows), while under pressure ? Sorry for the lame markup, paint on Windows XP isn't all that flexible.

I had the hose disconnected as I just replaced my F-hose and bypass valves, and thought I would continuing pressure testing (from the turbos), before reconnecting the hose and clip. If part #9 is supposed to act as a check valve blocking air from entering hose part #6 from the intake plenum behind the throttle bottle, then it looks like I may need to replace this also.




Much appreciated.

 

I think that it should not let air out it to line #6 I will check in the am. That is for the brake booster so that should only see vacuum. When the TB is closed boost/ vacuum enters #12 then over the venturi and into the plenum threw #11 to pull a vacuum on line #6 I do no use that piece any longer and have not noticed any side effects. Not sure its a good idea though so not recommending anyone to remove it.

 

that part. Since it's connected to the intake plenum, I figured it shouldn't bleed air to part #6 under pressure. Glad I checked it while it was disconnected, otherwise I may not have caught it.

Let me know what you find, as before, thank you for your assistance

 

Man I HATE that little piece of plastic. I mean really hate it.

Mine failed where the little venturi mates to the top piece. It took me forever to find it, as I could not see the bubbles from my soap spray.

darn thing is expansive too .. . . .

Tom

 

Appears that there is a check valves built into the end that attaches to hose part #6. I have air escaping here when I pressure test.

 

I found them leak around the outer rim and yes they are expensive...

 

I do not use that piece as I stated, I found it (lucky) and it in fact is a check valve too! It will not let air back feed into hose #6,

 

Pelican.

Are there any other check valves I should be checking that are prone to failure ?

 

How about the one for the oil sump? Off the top of the sump tank a line goes to the plenum.

 

That one failed on me too . . .passenger side just off of the top of the T-plenum.

Just to add to the fun of pressure testing, I actually had a crack that was at the base of one of the nipples on the top of the T-plenum. I epoxied it . . and it only held for a few months. I replaced the unit with cayenne TB and a new T-plenum.