Can i remove the vbsv?
- Thread starter turbomk3
- Start date
Nothing like a pair of broken nipples to spoil your day eh? If you don't have the evap canister installed (you should vent the fuel tank down low btw) you don't need the vacuum bimetallic switching valve. Just be sure to cap off the port on the throttle body or anywhere along the pipe leading to it.
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NDBoost
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hate to thread jack but:
When you remove the charcoal canister are you supposed to still vent the fumes? I just capped the vapor line off but now i get alot of buildup pressure when i remove the fuel cap.
When you remove the charcoal canister are you supposed to still vent the fumes? I just capped the vapor line off but now i get alot of buildup pressure when i remove the fuel cap.
Yes you should still vent the tube to relieve the pressure in the gas tank,just run a hose on it and vent it to the bottom of the car.Sabotage said:
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NDBoost
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Yeah, you need to vent the fuel tank. Gasoline has a pretty high vapor pressure. Spill some on the ground and it's flashes (evaporates) off in a few minutes. If you block the tank vent line those vapors have nowhere to go so tank pressure builds up, epsecially when the fuel is warm.
A little tech for those who don't know: The EVAP (evaporative emission system) takes these fuel vapors and stores them in the charcoal canister to be later burned in the engine. We tend to think about HC as a tailpipe emission but the EVAP system is there to prevent HC in the fuel tank from escaping into the atmosphere.
Why charcoal? Because of it's huge surface area relative to it's size (it's charcoal from palm trees if anyone cares). It stores the fuel vapors through a process called adsorption (not absorption. The vapors stay in the canister until the VBSV senses the coolant temperature is hot. It then applies intake vacuum to the canister through an orifice located under the throttle plate. As the vapors are removed from the canister air is draw into the fuel tank through a check valve in the gas cap, equalizing the tank and preventing a vacuum from occuring. This check valve is the reason your gas cap is tested during a smog check. Of course, if you've removed the canister this is all a moot point
I'd go to the auto store and buy a vacuum cap to plug the throttle body port. Using a screw in a broken VBSV nipple works but is a hack job. Hack jobs usually equal trouble over time.
A little tech for those who don't know: The EVAP (evaporative emission system) takes these fuel vapors and stores them in the charcoal canister to be later burned in the engine. We tend to think about HC as a tailpipe emission but the EVAP system is there to prevent HC in the fuel tank from escaping into the atmosphere.
Why charcoal? Because of it's huge surface area relative to it's size (it's charcoal from palm trees if anyone cares). It stores the fuel vapors through a process called adsorption (not absorption. The vapors stay in the canister until the VBSV senses the coolant temperature is hot. It then applies intake vacuum to the canister through an orifice located under the throttle plate. As the vapors are removed from the canister air is draw into the fuel tank through a check valve in the gas cap, equalizing the tank and preventing a vacuum from occuring. This check valve is the reason your gas cap is tested during a smog check. Of course, if you've removed the canister this is all a moot point
I'd go to the auto store and buy a vacuum cap to plug the throttle body port. Using a screw in a broken VBSV nipple works but is a hack job. Hack jobs usually equal trouble over time.
shouldn't need to block off the broken nipples. just leave them be if you don't wanna remove the whole assembly and plug it.
QUESTION Here: so for venting the tank after you remove the Charcoal can.... run a vacuum hose from the vent hose down low right? just zip tie it or something down below? that's not dangerous? I take it you still have a check valve inline so it'll only vent when the tank has pressure??? should you keep the check valve inline when not running the charcoal can?
QUESTION Here: so for venting the tank after you remove the Charcoal can.... run a vacuum hose from the vent hose down low right? just zip tie it or something down below? that's not dangerous? I take it you still have a check valve inline so it'll only vent when the tank has pressure??? should you keep the check valve inline when not running the charcoal can?
Supra5MGTE said:
Yes, just leave it. But plug the port on the TB or you'll have unmetered air.
Not dangerous. In fact that was one way it was done before emissions testing came along. Much like the old draft tubes took care of PCV. What could be a tad risky is just leaving it to vent into the engine compartment (especially near the turbo) but even then the odds are it'll be no problem. No need for a check valve in the line. Choosing to keep the stock gas cap is your choice after doing this as it's check valve no longer serves any purpose. The tank will breathe (be equalized) through the vent hose..
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jetjock said:
Ok, b/c in my 4runner I'm not running a charcoal can and I have the metal vent line under the hood caped off and I get a lot of pressure in the tank. I guess I'll attatch some vacuum hose to it and zip tie it somewhere below.
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NDBoost
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Sorry, my mistake. What we have here is a failure to communicate. I thought you were talking about jamming a screw into one of the broken nipples. If you mean removing the VBSV altogether than sure, go for it. Just be sure to plug the vacuum port on the TB.
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NDBoost
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why not weld the hole and grind/polish the entire housing, that way there is no tacky bolt sticking out.
Sure. Or use the bolt, cut it off flush, then weld and grind/polish. Lots of ways to do it depending on what his capabilities are or what he's willing to pay. Kind of overkill though. I'd also point out the more permanently he messes with the emissions systems the less the car will be worth down the road to someone in a state where the stuff is required.
Hey Guys, Best thing to do is cap off the vent line and buy a venting gas cap for the store. That way it keeps the fumes away from the engine. Also I capped off my vbsv with a small brass NPT plug I got from the hardware store and it looks good.
Yep, thats the other way they did it in the old days. Or open up the check valve in the stock cap and plug the metal line in the engine bay. As long as the tank can breathe.
I didn't realize that valve port was NPT so his bolt idea isn't going to work. Sounds like the brass plug is the way to go. They come nickel plated too and if he gets the recessed type with an allen head instead of the hex or square it'll look even better.
I didn't realize that valve port was NPT so his bolt idea isn't going to work. Sounds like the brass plug is the way to go. They come nickel plated too and if he gets the recessed type with an allen head instead of the hex or square it'll look even better.
hhmmm I like the idea of a venting cap more than having fumes in my engine bay. and I off-road a lot too... so a hose would probly get ripped off eventually. or somin.