Why does my BVSV keep breaking on my Supra?

And what effect does it have on the system? I noticed that my fuel economy
started getting BETTER, and then a cursory check of the fluid leves revealed
the darn thing had broken AGAIN! The last time it broke, we put a screw in
the tube to block it, and capped the broken part. This time, it broke
without my knowledge. All I know is, 1. Fuel Economy jumped up quite a bit;
noticeable, at least (My speedo is not working, but since I usually drive a
regular route every day, I noticed it took less to fill the tank than
before) and 2. There is a smell of gasoline worse than before (I had been
unable to find a filler neck, but with the new tank installed, I can fill it
to half without any spilling or orders...now there is a more pronounced
smell of gas more often).

A check of the TSRM reveals:

[url]http://www.cygnusx1.net/supra/library/TSRM/ec/EC_06.html[/url]

If you look at the diagram, you will see the number (1), pointing to the
Check Valve in the charcoal cannister. Follow that line to the BVSV; the
broken fitting is at the end of this line, at the BVSV. This is interesting,
since, according to the diagram, the flow is FROM the tank, to the
cannister, through the BVSV and on to the Throttle Body, where it is marked
PURGE. I would have thought the flow would have been BACK to the tank!

So, any ideas on what this does, how I can fix it or eliminate it? This is
part of the EVEP Emissions system, so I am presuming the car will not pass
it's next inspection in April if I don't do something!

"Hachiroku" <Trueno@ae86.GTS> wrote in message
news:E2RPg.2441$zs6.946@trndny07...[color=blue]
> And what effect does it have on the system? I noticed that my fuel economy
> started getting BETTER, and then a cursory check of the fluid leves
> revealed the darn thing had broken AGAIN! The last time it broke, we put a
> screw in the tube to block it, and capped the broken part. This time, it
> broke without my knowledge. All I know is, 1. Fuel Economy jumped up quite
> a bit; noticeable, at least (My speedo is not working, but since I usually
> drive a regular route every day, I noticed it took less to fill the tank
> than before) and 2. There is a smell of gasoline worse than before (I had
> been unable to find a filler neck, but with the new tank installed, I can
> fill it to half without any spilling or orders...now there is a more
> pronounced smell of gas more often).
>
> A check of the TSRM reveals:
>
> [url]http://www.cygnusx1.net/supra/library/TSRM/ec/EC_06.html[/url]
>
> If you look at the diagram, you will see the number (1), pointing to the
> Check Valve in the charcoal cannister. Follow that line to the BVSV; the
> broken fitting is at the end of this line, at the BVSV. This is
> interesting, since, according to the diagram, the flow is FROM the tank,
> to the cannister, through the BVSV and on to the Throttle Body, where it
> is marked PURGE. I would have thought the flow would have been BACK to the
> tank!
>
> So, any ideas on what this does, how I can fix it or eliminate it? This is
> part of the EVEP Emissions system, so I am presuming the car will not pass
> it's next inspection in April if I don't do something!
>
>[/color]

The BVSV - bimetallic vacuum switching valve - is basically a valve that
opens and closes at a set coolant temperature. I think you can connect the
vacuum hoses going into and out of the BVSV together and not encounter any
problems after the engine is warmed up although you may experience some
drivability problems during warm-up.

Basically, the BVSV opens after the engine is warmed up and purges the
vapors stored in the charcoal canister into the intake, where the vapors are
sucked into the combustion chamber to be burned.
--

Ray O
(correct punctuation to reply)