I am wondering what is the black stuff (carbon looking sand thingy) in the fd catch can? The can has two line going into it. One line comes from the fuel tank and one goes into the purge control. Are these stuff suppose to be there, or are they build up of some sort.

 

that looks like dried coolant dripped from the tb coolant hose

 

That's the charcoal canister, part of the fuel stystem.

 

Charcoal canister is under the car by the fuel tank.

 

I am talking about the stuff that is on the inside..

 

take a better picture too damn blurry

 

You probably should not be opening it up. Usually it's glued shut and should be replaced if it shows signs of leaking. It's known as the "Catch tank". The other line goes to the charcoal canister by the rear axle which then goes to the gas tank vent. The stuff in there is probably charcoal/carbon.

Here's my guess on it's purpose. If the gas tank is full (or over full), gas may be sucked/forced into the Charcoal canister. When the purge control solenoid is opened under vacuum (there's a check valve to prevent boost pressure to pressurizing your charcol canister and gas tank), gas instead of gas fumes may be pulled into the engine causing rough running/stalling. The Catch tank stops this by seperating the gas from the gas fumes. Maybe they expect under hood temps will evaporate any gas that gets pulled forward. Again, my guess.

 

There's a charcoal canister in the engine bay, it bolts on the underside of the elbow.

 

Could someone expand on this? My "catch tank" looks to be leaking quite a bit and I'm suffering from rough idle/stalling after hard boosting.

And if I were to call up Malloy Mazda and ask for a replacement, would I just need the catch tank itself or the lines going to and from it as well?

 

Sounds like you may have a problem with one of the check valves. I would start checking there--no pun intended.

 

Thanks. Sounds pluasible, but the previous owner replaced all of them with Viton check valves about two years ago. It's certainly worth checking and shouldn't be too hard as long as they're not in the worst locations possible.

I'm still intrigued as to what a faulty catch tank (under the TB elbow) could cause.