Dan Martinic

Performing a vacuum pressure test at .5 bar (7 psi), I get this buzzing from these parts near the brake booster. The parts are also vibrating. I don't know what they even are (?) or if this is normal.

Video of situation (crank up the volume):


Thank you to any who reply

odonnell

Sounds like the diaphragm is torn and it's fluttering, like the hole on a whoopee cushion. They're evap system parts responsible for ingestion of fuel tank vapors.

mj951

Those parts are part of the emission system. I'm not an expert on their exact function and flow but basically it puts fuel vapors back through the intake to reduce emissions. There is a plastic 'tank' behind the front fender lining as part of this system, also ties back to the fuel tank. Many of us have eliminated this plumbing from the car and capped the line at the fuel tank with a small air filter. Eliminates vacuum leaks, reduces weight some (4#'s) and cleans up the engine bay a little which is always nice. If the car has to pass an emissions test I would not eliminate the system.

The buzz and vibration you are experiencing is a leak, not normal.
Edit: or torn diaphragm as odonnell suggests...

Dan Martinic

Gentlemen, thank you. I have to pass emissions. The black part I've located around $30 OEM; the bronze part--a control valve--is a whopping $400+.

Guess I should figure out which is busted.

Curious: the emissions test for my car is a probe in the exhaust. Since there is no OBD connection, would it pass if this system was removed?

rlm328

As stated this is part of your gas tank vapor system.

It has nothing to do with an exhaust gases test.

mj951

True. I shouldn't have stated so strongly that I wouldn't remove the system if I had to pass emissions. I've never had to pass an emissions test, on any of my cars, so I'm not at all familiar with the test.

You may smell more gas fumes with the system removed and I suspect if an inspector notices the air filter at the back he might look further and see a system has been removed, not like what he sees. Don't know.

Dan Martinic

Hmm.. I always watch and never see anyone do a visual under the hood. I'm going to replace the cheap diaphram part--pinching its hose changed the sound.

I spent the day taking off the intake manifold. Despite all the procedures I've read, nothing prepared me for the problem of injectors not budging! I ended up unclipping them and with a pry bar, managed to lift off the fuel rail with two injectors stuck to it, leaving two in the manifold.

I can't imagine the pain of forcing them back in.. with new o-rings even.

Meanwhile, all that talk of manifold allen bolt problems... and they turned easy as butter. Strange!

Speaking of 'it didn't say that'... I cannot see how it's easy to change AOS seals with the intake off? The Pelican Parts write-up suggests the turbo has to come out. Am I missing something?

That... and after removing the bolt that holds the dipstick tube, the tube moves up and down as if not attached to anything!

Something tells me that this vacuum leaks job isn't nearly as simple as all the internet suggests

Humboldtgrin

It depends on the smog tech. It's a $40,000 fine for them personally if they are found guilty of not performing a smog test properly. Smog techs will look under the hood to see if it's there. It doesn't take but a glance for some veteran smog techs. 33% of emotions are evap related so I would recommend fixing that. Especially if your in California and live in an annual or biannual smog area.

Tom M'Guinn

What state/county are you in?

Dan Martinic

Toronto, Ontario, Canada. The emissions testing starts model year 1988 and up; my 951 is a 1988. Dang!

Tom M'Guinn

Bummer, so close... Can't help you at all on Ontario smog rules. I can tell you in California that evap system doesn't get tested because the tank in the fender is inaccessible. That said, if the intake track is leaking there (or anywhere) you'll want to fix it anyway...

Humboldtgrin

In California the only evap item that gets tested is the gas cap. Everything else evap is visual. However it does need to match the evap diagram sticker under the hood. OBD2 cars run an evap test and will not pass smog if they have an issue.

mj951

Turbo needs to come out to replace AOS seals.

The bolt at the top of the dip stick tube is the only fastener for the tube, bottom has a taper that fits a hole in the block. Good time to replace the O-ring.
That bolt is one of the worst in the engine bay.