For cross reference, the vc120 fit 1992-1996 Chevrolet Luminas. If you find an aftermarket canister for that application, you should be good to go. O'riellys part #CP1018.
Charcoal Canister
- Thread starter MKPNG
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Not sure if you are looking at me, but I was posting an option for the VC120, not the OEM canister. I think all you need to make the original bracket work with the VC120 is a couple longer screws. At least that's what I understand.
Cool, then the records clear for someone that stumbles into this thread a year from now that does not share you particular affliction.
I am pretty much OEM everything, barring a very few non mechanical parts that can't disable my vehicle.
I hate to beat a dead horse, but if the gas cap allowed air into the tank, it would also let pressure out. Most filler tubes have a metal flap at the top that prevents air going either way. The vent tube goes to the canister for overfills and vapor escape, but it's other function is to allow air to fill the void created by fuel moving out of the tank (preventing vacuum) If you take a 2 liter bottle of soda and turn it upside down, the soda slowly chugs out of the bottle (due to void creating vacuum) if it was under pressure, it would come out like a firehose.
That metal flap is not air tight. Most filler necks have vapor bypasses around that flap. Imagine the problems when you activate the flap with the gas pump spout if it was air tight. Whenever I put Stabil in my tank, I only dump it into the neck, never past the flap, and it drains down around the flap very easily on all my trucks, including the 2013 Toy. Im not saying the canister doesn't supply air to the tank as volume drops-it does have a fresh air supply port. But petroleum based fuel vapors tend to expand to fill whatever volume they are in, especially when the liquid is agitated. And as the pressure drops in the tank from a reduction in liquid volume, more of the liquid remaining will take a gaseous form. The PVTs of gasoline determine what that volume is. Slight changes in the P and T make a huge difference. Pressure is exponential.
Your gas tank needs to breath in, to allow air to displace the gas pumped out and when the gas contracts during cooling, and out, because the volume in the tank increases (1) when you fill it, (2) when the gas warms up in the sun, and (3) when the fuel is agitated as you drive (agitated fluid takes up more volume). In order to allow it to breath while still preventing hydrocarbon molecules from getting into the atmosphere, it breaths in and out through an activated charcoal bed. The component that contains this is called the "charcoal canister". The charcoal catches hydrocarbon molecules in air that's escaping the tank, and when you start the car a solenoid-operated "purge valve" and allows the HC to be drawn into the engine's intake system and burned.
If the vent line to the canister becomes blocked or kinked, or if the charcoal bed becomes saturated with gas, the tank will be unable to breath in. A vaciuum will form in the airspace and the vacuume will prevent the pump from being able to pump gas out. It also places excess stress on the pump and can cause premature pump failure.
I've attached an "exploded view" drawing of my owne system just to illustrate the typical system. I don;t heva one specifically for your system, but I'm coonfident that it'll be similarly constructed.
If the vent line to the canister becomes blocked or kinked, or if the charcoal bed becomes saturated with gas, the tank will be unable to breath in. A vaciuum will form in the airspace and the vacuume will prevent the pump from being able to pump gas out. It also places excess stress on the pump and can cause premature pump failure.
I've attached an "exploded view" drawing of my owne system just to illustrate the typical system. I don;t heva one specifically for your system, but I'm coonfident that it'll be similarly constructed.
I too hate to beat a dead horse, but you are again incorrect about the gas caps. Think "check valve". Evap is designed to be "one way" as pressure builds in the tank (opposite of what you are arguing). But, there is nothing preventing a tanks pressure less than atmospheric to be equalized through the evap system. But, that isn't the intention or common use for it.
ARE FUEL CAPS FOR TODAY'S CARS VENTED?
Fuel caps have not been fully vented since the 1960's. Modern fuel caps typically have valves that relieve positive and/or negative pressure once it reaches a certain level. it depends what cap you have and weather or not your roll-over valve and purge valve are operational.
Fuel caps have not been fully vented since the 1960's. Modern fuel caps typically have valves that relieve positive and/or negative pressure once it reaches a certain level. it depends what cap you have and weather or not your roll-over valve and purge valve are operational.
Most systems are designed in the following manner, specifically the 80 series landcruiser.
If p tank is greater than p atmosphere, excess pressure is discharged through the evap system. At least it is supposed to.
If p tank is less than p atmosphere, air is brought in through the gas cap.
You argued that if a gas cap allowed air in, it has to allow air or gas to escape. False. What happened in the 1960s only applies if we are talking 1960 systems. Modern gas caps allow air in, but won't "vent" except in extreme cases.
You're a little off base on the function of charcoal, but no more so than thinking the charcoal canister is a replacement item.
If p tank is greater than p atmosphere, excess pressure is discharged through the evap system. At least it is supposed to.
If p tank is less than p atmosphere, air is brought in through the gas cap.
You argued that if a gas cap allowed air in, it has to allow air or gas to escape. False. What happened in the 1960s only applies if we are talking 1960 systems. Modern gas caps allow air in, but won't "vent" except in extreme cases.
You're a little off base on the function of charcoal, but no more so than thinking the charcoal canister is a replacement item.
Wayne
Bought by His blood, kept by His power
^ X2
Is the charcoal canister not a replacement item? I just replaced mine. Kept the old one just in case, but it was not "easily" serviceable. Does the charcoal ever go bad after it is saturated with too many heavies or can it be reused after removal and an extended period of "degassing"?
Im serious with this question, not arguing.
Technically, the charcoal can" recover" from "heavies". It certainly doesn't ruin it. My theory, not based on a statistical dataset, is that the vent line or inlet at the vent line becomes clogged. Dust could even do this. Fsm specifies to blow it out with air. I also will check tsv and vsv for functionality before replacing the charcoal canister. I got an old one from 97, but I need to finish my swap before I start screwing around with charcoal canisters.
I don't think the charcoal in these is going bad, it's the check valves built into the canister. I opened mine up, cleaned the valve, and replaced the charcoal (but only since I already had it open). It worked for awhile, but the check valve seems to have become stuck because I'm experiencing gas tank pressure again. Perhaps I didn't clean it well enough, or perhaps it's worn in some manner that makes it want to sick. Either way, I'm tired of trying to get the OEM canister to work. I think I'm just going to go ahead and put in a VC120.
Probably should have done that first, but replacement did solve the problems. Ill keep the old one for the next LC
bmorgan
SILVER Star
Might seem like a dumb question, but is there any reason why you can't just clean the valve with some carb cleaner without opening up the canister by spraying some in the tank port, letting it sit, then applying some compressed air to it? If it's not working as it is, might be worth a shot. Thoughts?
I used the AC Delco model off the rainforest site. The VC120 didn't have the fresh air nipple on top and I didn't bother to check the bottom. In boulder county, the air police get to snooping around the engine bay and I didn't want to chance it
Worth a shot. I had to run alot of cleaner and compressed air on mine to get it to flow freely. I wouldn't want to spray a ton of the cleaner into the charcoal, but I doubt a little will hurt it.
Could use something like lectra motive or maf cleaner. Time, fresh air and heat will heal all charcoal wounds.
