348 charcoal canister

I don't know where it is in your engine compartment, but I've got one too. It's part of the emissions control system and traps fuel vapors. We have to try to keep our air free of hydrocarbons.

 

The charcoal canister is the item shown in the attached picture, Ferrari part #138419. The Workshop Manual says it should be replaced every 80,000 km.

There is a detailed description of its operation in the Shop Manual, but the condensed version in the Owners Handbook says:

"The fuel vapors from the fuel tank flow into the charcoal canister where they are absorbed and stored when the engine is not running. When the engine is running, the fuel vapors retained in the charcoal canister are purged through a line which conveys them to the intake manifold."
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Some people say that the charcoal is for emissions, but my own opinion is that it is for safety. I could be wrong, but it seems to me that storing explosive gas vapors is safer when absorbed by charcoal and later purged back into the intake than if the gas vapors were simply allowed to accumulate in a half-full gas tank...sort of like storing nitroglycerine in silica (i.e. dynamite) rather than in a half-full glass bottle.

 

Miltonian gets the "Fchatter of the Day" award for two over-the-top generous posts: 1. measurement of center console piece, 2. pointing toward the charcoal canister with an old pool cue.

 

Thank you for the award, I'm sure the voting was unamimous.

One small correction, that isn't an old pool cue, it's an old graphflex arrow shaft.

My lovely assistant will demonstrate the proper method of pointing at a charcoal canister with an old pool cue. Please, a big hand for my lovely assistant!
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Sort of. Here's the deal: you need to vent your gas tank(s) somehow, or as the gas level goes down, you get a vacuum and no more fuel flow (or collapse the tank itself?). Back in the day, we had vented gas caps, so the fumes went into the air. This does create a lot of pollution, especially in cities.

So the solution is you have a rubber hose at the top of the tank leading to a charcoal cannister; but raw gas will ruin the charcoal so usually one has a catch can first. Gas in there eventually evaporates and then goes to the charcoal cannister. Another hose will then vent what's not absorbed back into your intake manifold or carburetors if you have them. The throttle opening eliminates the vacuum problem.

Gas fumes are safe in the tank, but you can't run a closed system.

Ken