This is actually a check to make sure that raw gas vapors, a mojor smog
factor, are not being released into the atmosphere.  This check is for
all cars with a charcoal canister system.  I'm not sure of the date that
they started being used but my '74s have all had them and have been
checked in each Illinois smog check since they started.  Actually I'm
kind of suprised that CA hasn't been checking them until now.

Chris Smith
Chief Gas Sniffer, T.U.R.D.

westydriver wrote:

> this has been going on all the time in colorado and a few other places.
>  it is only for vehicles where the gas cap seal is actually part of the
> emissions system.  this would be many cars since about 1990.  many
> injected cars actually pressurize the entire fuel system and this keeps
> fuel vapors from being pumped into the atomosphere, and on some cars it
> definately effects your performance as well.   on some cars a
> diagnostic check actually has a step to check and make sure the gas cap
> is sealing correctly.
> jimt
> On Wednesday, Nov 13, 2002, at 18:58 America/Denver, Joseph Fortino
> wrote:
>
>> smog check now checks gas caps for pressure? total weirdness if you
>> ask me
>> it can fail the test if your cap has a micro crack?? anyway heads up
>> calie4nia people
>>
>> another rule in the world of cars!
>>
>> Joe
>>
>>
>