I've got connections with nothing connected

[autobonrun]

You guys are definitely a good influence. While waiting on parts I started detailing the engine and noticed a few items that may not be right.

There is an oval black cannister on the right side of the engine compartment with a nipple that points toward the rear of the car. Should there be a hose connected to it? Right now it's just open.

Also, directly below and in front of the oil filler pipe is a hollow threaded connection that extends up through the bottom of the engine compartment. Is this just a vent or should something be connected to it?

Lastly, it appears there is oil at the seal where the oil fill pipe enters the side wall. I'm trying to verify if this is just splatter or an actual leak. If leaking, how do you replace that seal?

79SC

[stormcrow]

The black box you speak of is the emmission charcoal canaster which has a hose connected to it on the other side coming from fuel tank evaporative control system. If you look on the drivers side of the air box on the engine you will see a nipple pointing out towards the side wall. A hose should go from the charcoal cannaster to the air box.

Steve

[Early_S_Man]

The hollow-threaded part is just a brace for the oil tank.

As for the oil tank leak ... probably the easily-changed O-ring between filter base and tank ... check this thread:

http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=55096

[autobonrun]

Originally posted by stormcrow
The black box you speak of is the emmission charcoal canaster which has a hose connected to it on the other side coming from fuel tank evaporative control system. If you look on the drivers side of the air box on the engine you will see a nipple pointing out towards the side wall. A hose should go from the charcoal cannaster to the air box.

Steve

The nipple on the drivers side of the airbox has a hose as you mention, but it is connected to the larger of two nipples on the back of the cannister nearest the firewall. A smaller nipple also on the back of the cannister has hose that goes off underneath the engine but I can't tell where. However the nipple on the front of the cannister nearest the oil fill has nothing. This is the one I'm wondering about. Maybe my entire setup is incorrect? Or maybe it went to the air pump which was removed several years back. I'll try to find a diagram of an emissions system to look at. Does this emissions stuff have any impact on the car's performance or does it just make the EPA happy.

Thanks

I also found that the nipple on the passenger side of my airbox that goes to the vent on the oil fill tube had broken off. I was able to fix it using a threaded conduit connector normally designed for a electrical Junction Box. This worked great.

+++++=

Followup:

After you told me what the cannister was, I located a Clymer maintenance manual which shows the setup. Evidently on 74-77 911's, the hose on the front of the cannister was for a fresh air intake from the fan housing. On 78 and later 911's this hose was discontinued.

The small hose I mentioned on the back of the cannister goes to the expansion tank which in turn is connected to the vapor space on the fuel tank. The larger hose on the back takes the fuel tank vapors directly to the airbox just as you stated.

I'm sure most (except me) already know this but I discovered the purpose of the hose from the passenger side of the airbox to the oil fill tube is to collect crankcase vapor (piston blowby). The vapors from the crankcase are routed to the oil tank for collection. Now I understand the source of the small amounts of oil that collect in my airbox. Reading does wonders!