Charcoal Canister.. please explain
04-22-2009, 05:41 AM
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Charcoal Canister.. please explain
hey guys and gals..
So.. as some may know, I have been battling high CO levels and failing emissions... replaced and repaired just about everything under the hood..inlcuding a rebuild 8 months ago...
so heres my question.. WHAT DOES THE CHARCOAL CANISTER DO?? Here is why I ask... aside from failing emissions, my idle has been jumpy and inconsistant.. Last night I found a big hole in the hose that runs from the top of the canister, around the back of the engine, and connects onto a line (marked a/c..tvv).. (reading off the vaccuum diagram on hood).. I replaced the hose but didnt feel much difference... Was this hole causing me problems?
ALSO.... the hose that runs OUT OF THE BOTTOM of the charcoal canister..WHERE DOES IT GO???? I followed it and it seems to just be hanging out below, doest connect to anything... Is this right? Would these issues cause the high CO levels and jumpy idle?
anything you can offer is appreciated...
Neal
So.. as some may know, I have been battling high CO levels and failing emissions... replaced and repaired just about everything under the hood..inlcuding a rebuild 8 months ago...
so heres my question.. WHAT DOES THE CHARCOAL CANISTER DO?? Here is why I ask... aside from failing emissions, my idle has been jumpy and inconsistant.. Last night I found a big hole in the hose that runs from the top of the canister, around the back of the engine, and connects onto a line (marked a/c..tvv).. (reading off the vaccuum diagram on hood).. I replaced the hose but didnt feel much difference... Was this hole causing me problems?
ALSO.... the hose that runs OUT OF THE BOTTOM of the charcoal canister..WHERE DOES IT GO???? I followed it and it seems to just be hanging out below, doest connect to anything... Is this right? Would these issues cause the high CO levels and jumpy idle?
anything you can offer is appreciated...
Neal
04-22-2009, 06:00 PM
#2
Part of your EVAP system:
EVAPORATIVE CONTROLS
Gasoline evaporates quite easily. In the past, these evaporative emissions were vented into the atmosphere. 20% of all HC emissions from the automobile are from the gas tank. In 1970 legislation was passed, prohibiting venting of gas tank fumes into the atmosphere. An evaporative control system was developed to eliminate this source of pollution. The function of the fuel evaporative control system is to trap and store evaporative emissions from the gas tank and carburetor. A charcoal canister is used to trap the fuel vapors. The fuel vapors adhere to the charcoal, until the engine is started, and engine vacuum can be used to draw the vapors into the engine, so that they can be burned along with the fuel/air mixture. This system requires the use of a sealed gas tank filler cap. This cap is so important to the operation of the system, that a test of the cap is now being integrated into many state emission inspection programs. Pre-1970 cars released fuel vapors into the atmosphere through the use of a vented gas cap. Today with the use of sealed caps, redesigned gas tanks are used. The tank has to have the space for the vapors to collect so that they can then be vented to the charcoal canister. A purge valve is used to control the vapor flow into the engine. The purge valve is operated by engine vacuum. One common problem with this system is that the purge valve goes bad and engine vacuum draws fuel directly into the intake system. This enriches the fuel mixture and will foul the spark plugs. Most charcoal canisters have a filter that should be replaced periodically. This system should be checked when fuel mileage drops.
That saved a lot of typing, but I must give credit where credit is due: http://www.familycar.com/CLASSROOM/emission.htm
EVAPORATIVE CONTROLS
Gasoline evaporates quite easily. In the past, these evaporative emissions were vented into the atmosphere. 20% of all HC emissions from the automobile are from the gas tank. In 1970 legislation was passed, prohibiting venting of gas tank fumes into the atmosphere. An evaporative control system was developed to eliminate this source of pollution. The function of the fuel evaporative control system is to trap and store evaporative emissions from the gas tank and carburetor. A charcoal canister is used to trap the fuel vapors. The fuel vapors adhere to the charcoal, until the engine is started, and engine vacuum can be used to draw the vapors into the engine, so that they can be burned along with the fuel/air mixture. This system requires the use of a sealed gas tank filler cap. This cap is so important to the operation of the system, that a test of the cap is now being integrated into many state emission inspection programs. Pre-1970 cars released fuel vapors into the atmosphere through the use of a vented gas cap. Today with the use of sealed caps, redesigned gas tanks are used. The tank has to have the space for the vapors to collect so that they can then be vented to the charcoal canister. A purge valve is used to control the vapor flow into the engine. The purge valve is operated by engine vacuum. One common problem with this system is that the purge valve goes bad and engine vacuum draws fuel directly into the intake system. This enriches the fuel mixture and will foul the spark plugs. Most charcoal canisters have a filter that should be replaced periodically. This system should be checked when fuel mileage drops.
That saved a lot of typing, but I must give credit where credit is due: http://www.familycar.com/CLASSROOM/emission.htm
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