What does the BVSV do?

[oldsking]

Well both the tips are broken on mine so I have no vacuum hoses on it but the car runs pretty good.... What is the purpose since it's on top of the thermostat housing? Is there something not being done right on my car now?

I have a 7mge

 

[RazoE]

I believe it lets air enter the charcoal canister once the engine reaches a certain temperature...

not 100% sure though...

 

[WhtMa71]

It's a valve that opens once it reaches a certain temperature and allows vacuum, from the throttle body, to pull the fumes from the charcoal canister. A vent tube from your gas tank feeds the charcoal canister.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EC&P=4
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EC&P=6

 

[mirage83]

On a turbo model one line goes to the charcoal canister, the other goes to the throttle body. According to Cygnus on the GE it looks like one goes to the intake and the other to the #1 Vacuum Assembly piping.

http://www.cygnusx1.net/Supra/Library/EPC/291210/catalog.aspx?F=1708&P=2

 

[Steely]

so if you're not using a charcoal can where do those lines go? the plastic broke off my bsvs

 

[jdub]

Ummm...you need a charcoal canister. The check valve inside maintains positive pressure in the gas tank to prevent FP cavitation. Plus, you really do not want gas fumes in your engine bay

If your BVSV is broken, you can connect the 2 lines as a temporary fix...you still need to replace it.

 

[jetjock]

Hmmm. That GE diagram has to be a mistake. Doesn't make sense...

 

[jdub]

Has to be wrong...never noticed that in the EPC before.

Here's the GE TRSM diagram:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EC&P=3

 

[jetjock]

Yep. Why would ported vacuum be connected back into the manifold? Thought I was losing it there for a minute...

 

[ForcedTorque]

I often say that a few of you guys are smarter than Toyota.

 

[Moy]

I often say that a few of you guys are smarter than Toyota.

Haha, easily

 

[suprarx7nut]

Very strange picture in the EPC. In you go back through the NATO version for 89+ it shows a different routing, but it still doesn't look quite right. Odd.

Here is the correct location shown in an old photo from my bhg days:

On the very right side of the pic you can see the BSVS. One side goes to the charcoal canister(left), the other to the throttle body to pull vacuum.

 

[mirage83]

Yep. Why would ported vacuum be connected back into the manifold? Thought I was losing it there for a minute...

Oh well, that's what I get for relying on a Toyota diagram. Think we can get a group rate on amended TSRM's? Or better yet, perhaps a $$$ credit on future OEM parts for you and JDub pointing out their mistake? :biglaugh:

 

[SupraRon]

Ummm...you need a charcoal canister. The check valve inside maintains positive pressure in the gas tank to prevent FP cavitation. Plus, you really do not want gas fumes in your engine bay

A little off topic and I've been meaning to ask, but if I'm smelling gas fumes around the charcoal canister does it mean it is not working?

 

[oldsking]

ahhh now i know what it is, here I was thinking if has something to do with the coolant since it's on the thermostat lol

 

[Steely]

i didn't remove the charcoil can someone else did and put a vented gas cap

 

[jdub]

i didn't remove the charcoil can someone else did and put a vented gas cap

If that's the case, I'd be looking for replacements for both if I were you
FYI - a JDM Supra canister can be easily tucked away under the passenger wheel well.

 

[Jeff Lange]

Not all A70's had a charcoal canister. in all countries, and in Japan they didn't use a BVSV. Some countries had a check valve of some sort with some hoses, but no canister.

Does anyone have the diagrams/description for the Japanese and/or European evap systems? Just curious, as I'd like to see their setup and explanations.

Jeff

 

[jdub]

Yep...I've seen the motors without the BVSV. The line goes straight from the CC to the TB fitting. I assumed the BVSV was on US cars to meet US emissions (car warmed up 1st before vapor is purged from the CC)...could be a bad assumption.

Never seen car from the factory without the CC.

 

[Jeff Lange]

Yeah neither have I, just seen the diagram for it in the EPC.

On my 4A-GZE (J-spec 91 model) I don't have anywhere I can put a BVSV onto it, so I need to know if I should just attach vacuum to the Charcoal Canister, or if I need to do something else. I can't find any J-spec information for the GZE, so I thought I'd check out a JDM 7M setup, if someone has a pic, I'd appreciate it.

Jeff