BVSV Broke?

[Fubar231]

Alright, so the top nipple of my BVSV or whatever its called (Referring to the cygnus x1 thing http://cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EC&P=4 ) and its causing a vac leak. Heres the thing, i pulled out my charcoal canister and plugged off that vac line. By looking at the diagram, could i just plug off the vac line on TB that goes to the BVSV and just put a bolt or something where the BVSV is? I'm not entirely sure what it does, but i think its something emissions related. The reason i want this fixed is cause its causing a vac leak under throttle... Any input would be great!

Thanks,
Shane

 

[mk3_chris]

http://www.supramania.com/forums/showthread.php?t=108861
I know it's titled wiring woes, but we get into that what your asking, it basically says keep your egr shit in and get a new bvsv. I'm trying as well to find out what happens if you just bypass it and I'm basically getting bashed.

 

[Fubar231]

Thats no good to hear. Id rather not spend 40$ or so on something thats just being blocked off in the first place. I don't really see it causing any problem... Just want some input from the pros ya know.

 

[Poodles]

http://www.supramania.com/forums/showthread.php?t=108804&highlight=charcoal

Also, the BVSV is used on TONS of Toyotas over the years and is very cheap from a junkyard...

 

[mk3_chris]

What i proposed was to go from the charcoal can. to metal pipe where it would go from the bvsv. But apparently its a really bad idea according to Gaboonviper85.

 

[dbsupra90]

bvsv is a temp controlled valve. the vsv (like for the fuel pressure regulator) is controlled by voltage. the bvsv is instead triggered by a certain temp.

if you want the char canister system to work properly, you need to replace it. if you dont, then plug the vac side and use a plug for the thermostat housing.

 

[Fubar231]

http://www.supramania.com/forums/showthread.php?t=108804&highlight=charcoal

Also, the BVSV is used on TONS of Toyotas over the years and is very cheap from a junkyard...

I read through the section and basically just read that im venting flammable gasses 100 times. Enough said. Also, i just don't see the point of replacing it if im blocking it off. What are the downs of blocking it off? Can it cause any harm? Im listening to what people are saying (Not being hard headed) but im trying to get some answers and not just be told to do something. Like im saying, and just getting down to it, i don't see a reason to buy and replace something im just blocking off. What is the harm in blocking off the BVSV?

 

[mk3_chris]

Ok so its temp controlled i knew that, but what does it do other than put a vacuum on the tb?

 

[Fubar231]

bvsv is a temp controlled valve. the vsv (like for the fuel pressure regulator) is controlled by voltage. the bvsv is instead triggered by a certain temp.

if you want the char canister system to work properly, you need to replace it. if you dont, then plug the vac side and use a plug for the thermostat housing.

This is the info i was looking for. So just get a plug/bolt/something to block off where it screws into the t-stat neck then block the nipple off at the throttle body?

 

[Fubar231]

Ok so its temp controlled i knew that, but what does it do other than put a vacuum on the tb?

Its a giant loop. It pulls vacuum from the TB to pull the re-circulated exhaust gasses back in. At least, thats what ive gathered.

 

[mk3_chris]

Ok so why could you not just bypass it and always have a vacuum on the tb? Like have a vacuum line on the char can. goin to the metal pipe where it would have went from the bvsv?

 

[dbsupra90]

Its a giant loop. It pulls vacuum from the TB to pull the re-circulated exhaust gasses back in. At least, thats what ive gathered.

dont get confused with the egr. this is for gas vapor, not exhaust.

as far as making it a constant loop, i can't say. i don't understand the system enough to comment on that. why they made it temperature based i'm unsure. someone else can better explain that.

 

[mk3_chris]

someone else can better explain that.

I really wish someone would. I mean I completely understand it was done for a reason and probably shouldn't be messed with but why would constant vacuum hurt is my question.

 

[jetjock]

Purging the EVAP canister results in enrichment. Because of this the canister should not be purged when:

1) The engine is on idle. Because fuel control is sluggish (low O2 cross counting/low exhaust temp) the ported vacuum line from the TB prevents purging except when off idle, regardless of whether the engine is hot or cold.

2) The engine is cold. Purging at that time would be bad because the engine is already being supplied warm up enrichment by the ECU. Not to mention the engine isn't in fuel control when dead cold. To avoid further enrichment the BVSV prevents purging until coolant temperature reaches about 110 F.

Therefore the stock setup only allows canister purging to occur when the engine is warm *and* off idle. The ported TB vacuum and BVSV are simply used to make the EVAP and EFI systems play well together. The result is reduced HC emissions (both evap and tailpipe) and improved driveability. Defeating the EVAP system eliminates the need for both valve and port.

If you two are going to work on cars you ought to learn how shit works. At least RTFM...

 

[Poodles]

In a pinch I have seen people just connect the two vaccum lines. This will cause you to go rich though and should be fixed ASAP. It's arguable safer than letting gasoline vapors vent...

*cracks knuckles*

The charcoal canister (from here on called just CC) and it's vent to the engine is part of some emission standards in the world (US is one of them). In other parts of the world they still run a CC, but it's not vented into the engine. The CC does more than one function. It keep positive pressure on the gas tank to stop pump cavitation by way of the check valve. It's main function is to trap gasoline vapors from escaping into the atmosphere (as much as 20% of HC emissions from vehicles before the use of CC's was from fuel tank vents) and then either vent them back into the gas tank or into the engine.

EDIT: beat by JJ

 

[suprarx7nut]

DUDE, this is a VERY, VERY easy fix and is almost free.

-Find local junkyard
-Find nearly ANY Toyota from the late 80's through early 90's
-Find the BVSV (Follow vacuum lines coming from the throttle body)
-Wrench off BVSV (Vise grips work if you dont have a wrench large enough)
-Install new BVSV

I just picked one up and the yard didn't even want to bother charging me for it. If they do charge you, it'll be a couple bucks.

Don't cheap out on something that is necessary and VERY, VERY cheap and easy to fix.

 

[mk3_chris]

jetjock - Since your gonna be a dick, I'll play
1) Obviously you can't count cause there were 3 of us here.
2) RTFM i can only guess means "read the fucking manual" if you can find what you said in the manual send me a link and I'll be glad to read it because I looked.
3) I've asked 3 full time mechanics 2 at carolina chassis dyno, and one at ups that I've known for quite a while and they all told me "you don't need the egr but if your take it out just bypass whats broke". So i'm sorry for posting my question with people who will actually give me a better answer.

Poodles - Thank you. +1 for not being a dick.

 

[Fubar231]

Ok ill go ahead and get one. I just dont see the point as i removed the CC and blocked off the vacuum line going to the CC from the BVSV. But alright whatever, get a new one, hook the lines up and keep that one blocked off like i have it.

 

[Poodles]

jetjock - Since your gonna be a dick, I'll play
1) Obviously you can't count cause there were 3 of us here.
2) RTFM i can only guess means "read the fucking manual" if you can find what you said in the manual send me a link and I'll be glad to read it because I looked.
3) I've asked 3 full time mechanics 2 at carolina chassis dyno, and one at ups that I've known for quite a while and they all told me "you don't need the egr but if your take it out just bypass whats broke". So i'm sorry for posting my question with people who will actually give me a better answer.

Poodles - Thank you. +1 for not being a dick.

1) JJ is a bit harsh, but the info is available. The TSRM is the supra bible, read it in your spare time and learn a hell of a lot about your car.

2) http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EC&P=6

3) EGR has nothing to do with the CC/evap system.

Ok ill go ahead and get one. I just dont see the point as i removed the CC and blocked off the vacuum line going to the CC from the BVSV. But alright whatever, get a new one, hook the lines up and keep that one blocked off like i have it.

You're still not getting it. Blocking off that line just creates a nice big BOMB in the shape of your gas tank. No vent = high pressures.

 

[Fubar231]

2) http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EC&P=6

You're still not getting it. Blocking off that line just creates a nice big BOMB in the shape of your gas tank. No vent = high pressures.

Do you know which line im talking about? How would the line going from the BVSV to the CC cause tank pressure? Ive been told by several owners without it that its the bigger plastic line coming off the back that goes to the tank.

And off to read that stuff about #2

EDIT: Looking at number two, the link you posted above, i have the line from the BVSV to the CC plugged, but the line from the gas tank to the CC is routed into the fender. (Took a rubber hose and routed it into the fender to keep exhaust gasses out of the engine bay) so my tank is still venting.