Gents,
What is this box for?
It is a genuine Mitsu part and the lines (vacuum, I think) running to and from it are properly integrated with the rest of the plumbing in the engine bay. So I'm pretty convinced it isn't after market.
It seems to be fed from the inlet manifold, and then lines run from it down under the chassis. I haven't crawled around under the car to follow them - yet.
When inside the car, one can sometimes hear the faintest ticking - almost like a tappet, but not that "sharp". It also follows the revs - like a tappet would. I listened with a hollow pipe to the tappet covers and everything there is very quiet. One can hear the cams turning and working, but no ticking at all.
This morning coming back to my office after an off-site meeting, the ticking was there again. I investigated and now can confirm that the line from the manifold to the black box pulsates (when I wrap my hand around it) in time with the ticking.
So, I'm not worried about the ticking anymore and it is so faint that the interior fan (at it's slowest speed) drowns out that ticking.
Now I'm just curious.
Hope somebody can shed some light on this part and it's function.
Affiliate Member
it's called a fuel vapour canister
MR464470
MR464470
Marius,
I'm convinced it must be illegal to have so much knowledge and info at your finger tips
.
Now that I know what it is called, I promise to Google "fuel vapour canister" before begging you to tell me what the heck it does, except for the fact that it cans fuel vapour
I'm convinced it must be illegal to have so much knowledge and info at your finger tips
.Now that I know what it is called, I promise to Google "fuel vapour canister" before begging you to tell me what the heck it does, except for the fact that it cans fuel vapour
Affiliate Member
I just appear smart. I had no idea what it was when you posted so had to go into MMC ASA and look for it.
I also had to google to see what it does.
[BBvideo]http://www.youtube.com/watch?v=9io3_pxpibM[/BBvideo]
http://www.familycar.com/Classroom/emission.htm
Petrol 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.
So it seems older cars vented via the petrol cap. Yours is controlled by that canister so you lose less fuel via evporation.
I also had to google to see what it does.
[BBvideo]http://www.youtube.com/watch?v=9io3_pxpibM[/BBvideo]
http://www.familycar.com/Classroom/emission.htm
Petrol 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.
So it seems older cars vented via the petrol cap. Yours is controlled by that canister so you lose less fuel via evporation.
I wonder if the fuel smell many us V6 owners have experienced has something to do with this system malfuncioning, i.e. the purge valve not working correctly?
I'll go have a look if mine has a black box.
I'll go have a look if mine has a black box.
Pierre-Andre
2001 Pajero 3.5 GLS LWB
2001 Colt 3000i 4x4 D/C (SOLD)
2001 Pajero 3.5 GLS LWB
2001 Colt 3000i 4x4 D/C (SOLD)
I had a Lada Niva once....hey, don't laugh!...and that purge valve was sitting IN the car underneath the back side window. It was buggered and the whole car stenched of petrol until I gypoed the thing and all was well.
My Gen3 3.8V6 did not have this black box with-in sight anywhere. When the tank got a little on the low side, it had a good old expensive fuel smell about it.
Now I'm off to my car to check the maint. schedule for "Replace fuel vapour canister". Bet you guys a cold beer it isn't there.
Now I'm off to my car to check the maint. schedule for "Replace fuel vapour canister". Bet you guys a cold beer it isn't there.
I take Windhoek Lager, thank you.
I can not find any reference in the service book or the owner's manual to this elusive FVC.
"A purge valve is used to control the vapor flow into the engine. The purge valve is operated by engine vacuum" - This will be the faint ticking noise and the accompanying throbbing of the vacuum hose into the inlet manifold. I assume it only happens occasionally, based purely on the pressure inside the canister. When there is enough pressure behind the purge valve it will be activated by the inlet suction. But why in a ticking fashion at exactly the same tempo as the engine revs (like a tappet)?
"One common problem with this system is that the purge valve goes bad and engine vacuum draws fuel directly into the intake system." - Should I worry about the faint ticking/throbbing as it could indicate a purge valve gone bad?
"This enriches the fuel mixture and will foul the spark plugs. Most charcoal canisters have a filter that should be replaced periodically" - If I were to disconnect the the line into the manifold and blank that off and install a new line from the canister down to the bottom level of the motor, what are the likely pitfalls?
I can not find any reference in the service book or the owner's manual to this elusive FVC.
"A purge valve is used to control the vapor flow into the engine. The purge valve is operated by engine vacuum" - This will be the faint ticking noise and the accompanying throbbing of the vacuum hose into the inlet manifold. I assume it only happens occasionally, based purely on the pressure inside the canister. When there is enough pressure behind the purge valve it will be activated by the inlet suction. But why in a ticking fashion at exactly the same tempo as the engine revs (like a tappet)?
"One common problem with this system is that the purge valve goes bad and engine vacuum draws fuel directly into the intake system." - Should I worry about the faint ticking/throbbing as it could indicate a purge valve gone bad?
"This enriches the fuel mixture and will foul the spark plugs. Most charcoal canisters have a filter that should be replaced periodically" - If I were to disconnect the the line into the manifold and blank that off and install a new line from the canister down to the bottom level of the motor, what are the likely pitfalls?
Affiliate Member
vacuum on a petrol engine is linked to the rpm. The vacuum is caused by the piston moving down for the inlet stroke.
4eP,
Question: Is it possible that the Gen3 3,8 has a FVC? My Pajero builds up a high pressure in the fuel tank and then starts to literally stink. The only way of getting rid of this smell is to stop and open the filler cap to let the pressure out. Whilst still under maintenance plan I took it to the agents and complained about it. They took the pump out to check it for overpressure, they took the tank out to check for leaks (with an overpressure???), there is a small three way valve in the vent line that they replaced and they also replaced the fuel cap. All to no avail. These days, when my Pajero starts to stink, I stop, open the filler, and Bob is your uncle - all the stink is gone.
Any ideas??
Cloyd
Question: Is it possible that the Gen3 3,8 has a FVC? My Pajero builds up a high pressure in the fuel tank and then starts to literally stink. The only way of getting rid of this smell is to stop and open the filler cap to let the pressure out. Whilst still under maintenance plan I took it to the agents and complained about it. They took the pump out to check it for overpressure, they took the tank out to check for leaks (with an overpressure???), there is a small three way valve in the vent line that they replaced and they also replaced the fuel cap. All to no avail. These days, when my Pajero starts to stink, I stop, open the filler, and Bob is your uncle - all the stink is gone.
Any ideas??
Cloyd